JavaScript Object Creation Patterns

These samples demonstrate four different patterns for creating objects in JavaScript.

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These samples demonstrate four different ways of creating objects in JavaScript:
1. Object factory
2. Objects linking to other objects (OLOO)
3. Pseudo-classical object pattern
4. ES6 classes

Object Factory Pattern


function createStudent(name, year) {
  let courses = [];
  let notes = {};

  const getCourse = (key) => {
    return courses.find(obj => String(obj.code) === String(key));
  };

  return {
    info() { 
      console.log(`${name} is a ${year} year student.`);
    },

    listCourses() {
      console.log(courses);
    },

    addCourse(course) {
      courses.push(course);
    },

    addNote(code, text) {
      if (Object.keys(notes).includes(String(code))) {
        notes[code] += `; ${text}`;
      } else {
        if (getCourse(code)) notes[code] = text;
      }
    },

    updateNote(code, text) {
      if (Object.keys(notes).includes(String(code))) notes[code] = text;
    },

    viewNotes() {
      for (key in notes) {
        let courseName = getCourse(key).name;
        console.log(courseName + ':', notes[key]);
      }
    },
  }
}

function createStudent(name, year) {

let courses = [];

let notes = {};

const getCourse = (key) => {

return courses.find(obj => String(obj.code) === String(key));

};

return {

info() {

console.log(`${name} is a ${year} year student.`);

listCourses() {

console.log(courses);

addCourse(course) {

courses.push(course);

addNote(code, text) {

if (Object.keys(notes).includes(String(code))) {

notes[code] += `; ${text}`;

} else {

if (getCourse(code)) notes[code] = text;

}

updateNote(code, text) {

if (Object.keys(notes).includes(String(code))) notes[code] = text;

viewNotes() {

for (key in notes) {

let courseName = getCourse(key).name;

console.log(courseName + ':', notes[key]);

}

OLOO Pattern

This example also shows the use of WeakMap in an IIFE to hold private instance data.


const Account = (function() {
  const PWDERRMSG = 'Invalid Password';
  const Private = new WeakMap();

  function makeDisplayName() {
    let displayName = '';
    let randASCII;
    for (let i = 0; i < 16; i++) {
      randASCII = Math.floor(Math.random() * 94) + 32;
      displayName += String.fromCharCode(randASCII);
    }

    return displayName;
  }

  function pwdCheck(password, pvtObj) {
    return password === pvtObj.password;
  }

  return {
    init(email, password, firstName, lastName) {
      Private.set(this, {
        email,
        password,
        firstName,
        lastName,
      });

      this.displayName = makeDisplayName();

      return this;
    },

    email(password) {
      const pvtObj = Private.get(this);
      return pwdCheck(password, pvtObj) ? pvtObj.email : PWDERRMSG;
    },

    firstName(password) {
      const pvtObj = Private.get(this);
      return pwdCheck(password, pvtObj) ? pvtObj.firstName : PWDERRMSG;
    },

    lastName(password) {
      const pvtObj = Private.get(this);
      return pwdCheck(password, pvtObj)  ? pvtObj.lastName : PWDERRMSG;
    },

    resetPassword(password, newPassword) {
      const pvtObj = Private.get(this);
      if (pwdCheck(password, pvtObj)) {
        pvtObj.password = newPassword;
        return true;
      }

      return PWDERRMSG;
    },

    reanonymize(password) {
      const pvtObj = Private.get(this);
      if (pwdCheck(password, pvtObj)) {
        this.displayName = makeDisplayName();
        return true;
      }

      return PWDERRMSG;
    }
  }
})();

const Account = (function() {

const PWDERRMSG = 'Invalid Password';

const Private = new WeakMap();

function makeDisplayName() {

let displayName = '';

let randASCII;

for (let i = 0; i < 16; i++) {

randASCII = Math.floor(Math.random() * 94) + 32;

displayName += String.fromCharCode(randASCII);

}

return displayName;

}

function pwdCheck(password, pvtObj) {

return password === pvtObj.password;

}

return {

init(email, password, firstName, lastName) {

Private.set(this, {

email,

password,

firstName,

lastName,

});

this.displayName = makeDisplayName();

return this;

email(password) {

const pvtObj = Private.get(this);

return pwdCheck(password, pvtObj) ? pvtObj.email : PWDERRMSG;

firstName(password) {

const pvtObj = Private.get(this);

return pwdCheck(password, pvtObj) ? pvtObj.firstName : PWDERRMSG;

lastName(password) {

const pvtObj = Private.get(this);

return pwdCheck(password, pvtObj) ? pvtObj.lastName : PWDERRMSG;

resetPassword(password, newPassword) {

const pvtObj = Private.get(this);

if (pwdCheck(password, pvtObj)) {

pvtObj.password = newPassword;

return true;

}

return PWDERRMSG;

reanonymize(password) {

const pvtObj = Private.get(this);

if (pwdCheck(password, pvtObj)) {

this.displayName = makeDisplayName();

return true;

}

return PWDERRMSG;

}

})();

Pseudo-Classical Pattern


function Person(firstName, lastName, age, gender) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.age = age;
  this.gender = gender;
}

Person.prototype.communicate = function() {
  console.log('Communicating');

  const test = () => console.log(this);
  test();
}

Person.prototype.eat = function() {
  console.log('Eating');
}

Person.prototype.sleep = function() {
  console.log('Sleeping');
}

Person.prototype.fullName = function() {
  return this.firstName + ' ' + this.lastName;
}

function Doctor(firstName, lastName, age, gender, specialization) {
  Person.call(this, firstName, lastName, age, gender);
  this.specialization = specialization;
}

Doctor.prototype = Object.create(Person.prototype);
// Doctor.prototype.constructor = Doctor;
Object.defineProperty(Doctor.prototype, 'constructor', {
  value: Doctor,
  enumerable: false,
  writable: true 
});

Doctor.prototype.diagnose = function() {
  console.log('Diagnosing');
}

function Professor(firstName, lastName, age, gender, subject) {
  Person.call(this, firstName, lastName, age, gender);
  this.subject = subject;
}

Professor.prototype = Object.create(Person.prototype);
Professor.prototype.constructor = Professor;

Professor.prototype.teach = function() {
  console.log('Teaching');
}

function Student(firstName, lastName, age, gender, degree) {
  Person.call(this, firstName, lastName, age, gender);
  this.degree = degree;  
}

Student.prototype = Object.create(Person.prototype);
Student.prototype.constructor = Student;

Student.prototype.study = function() {
  console.log('Studying');
}

function GraduateStudent(firstName, lastName, age, gender, degree, graduateDegree) {
  Student.call(this, firstName, lastName, age, gender, degree);
  this.graduateDegree = graduateDegree;  
}

GraduateStudent.prototype = Object.create(Student.prototype);
GraduateStudent.prototype.constructor = GraduateStudent;

GraduateStudent.prototype.research = function() {
  console.log('Researching');
}

function Person(firstName, lastName, age, gender) {

this.firstName = firstName;

this.lastName = lastName;

this.age = age;

this.gender = gender;

}

Person.prototype.communicate = function() {

console.log('Communicating');

const test = () => console.log(this);

test();

}

Person.prototype.eat = function() {

console.log('Eating');

}

Person.prototype.sleep = function() {

console.log('Sleeping');

}

Person.prototype.fullName = function() {

return this.firstName + ' ' + this.lastName;

}

function Doctor(firstName, lastName, age, gender, specialization) {

Person.call(this, firstName, lastName, age, gender);

this.specialization = specialization;

}

Doctor.prototype = Object.create(Person.prototype);

// Doctor.prototype.constructor = Doctor;

Object.defineProperty(Doctor.prototype, 'constructor', {

value: Doctor,

enumerable: false,

writable: true

});

Doctor.prototype.diagnose = function() {

console.log('Diagnosing');

}

function Professor(firstName, lastName, age, gender, subject) {

Person.call(this, firstName, lastName, age, gender);

this.subject = subject;

}

Professor.prototype = Object.create(Person.prototype);

Professor.prototype.constructor = Professor;

Professor.prototype.teach = function() {

console.log('Teaching');

}

function Student(firstName, lastName, age, gender, degree) {

Person.call(this, firstName, lastName, age, gender);

this.degree = degree;

}

Student.prototype = Object.create(Person.prototype);

Student.prototype.constructor = Student;

Student.prototype.study = function() {

console.log('Studying');

}

function GraduateStudent(firstName, lastName, age, gender, degree, graduateDegree) {

Student.call(this, firstName, lastName, age, gender, degree);

this.graduateDegree = graduateDegree;

}

GraduateStudent.prototype = Object.create(Student.prototype);

GraduateStudent.prototype.constructor = GraduateStudent;

GraduateStudent.prototype.research = function() {

console.log('Researching');

}

ES6 Class

Private constants are not directly supported by ES6 class syntax. The way to create a private constant is to create a private getter method and return the constant value, as shown here in #PWDERRMSG.


 class Account {
  #email;
  #password;
  #firstName;
  #lastName;

  constructor(email, password, firstName, lastName) {
    this.#email = email;
    this.#password = password;
    this.#firstName = firstName;
    this.#lastName = lastName;
    this.displayName = this.#makeDisplayName();
  }

  get #PWDERRMSG() {
    return 'Invalid Password';
  }

  #makeDisplayName() {
    let displayName = '';
    let randASCII;
    for (let i = 0; i < 16; i++) {
      randASCII = Math.floor(Math.random() * 94) + 32;
      displayName += String.fromCharCode(randASCII);
    }

    return displayName;
  }

  #pwdCheck(password) {
    return password === this.#password;
  }

  email(password) {
    return this.#pwdCheck(password) ? this.#email : this.#PWDERRMSG;
  }

  firstName(password) {
    return this.#pwdCheck(password) ? this.#firstName : this.#PWDERRMSG;
  }

  lastName(password) {
    return this.#pwdCheck(password)  ? this.#lastName : this.#PWDERRMSG;      
  }

  resetPassword(password, newPassword) {
    if (this.#pwdCheck(password)) {
      this.#password = newPassword;
      return true;
    }

    return this.#PWDERRMSG;
  }

  reanonymize(password) {
    if (this.#pwdCheck(password)) {
      this.displayName = this.#makeDisplayName();
      return true;
    }

    return this.#PWDERRMSG;
  }
}

class Account {

#email;

#password;

#firstName;

#lastName;

constructor(email, password, firstName, lastName) {

this.#email = email;

this.#password = password;

this.#firstName = firstName;

this.#lastName = lastName;

this.displayName = this.#makeDisplayName();

}

get #PWDERRMSG() {

return 'Invalid Password';

}

#makeDisplayName() {

let displayName = '';

let randASCII;

for (let i = 0; i < 16; i++) {

randASCII = Math.floor(Math.random() * 94) + 32;

displayName += String.fromCharCode(randASCII);

}

return displayName;

}

#pwdCheck(password) {

return password === this.#password;

}

email(password) {

return this.#pwdCheck(password) ? this.#email : this.#PWDERRMSG;

}

firstName(password) {

return this.#pwdCheck(password) ? this.#firstName : this.#PWDERRMSG;

}

lastName(password) {

return this.#pwdCheck(password) ? this.#lastName : this.#PWDERRMSG;

}

resetPassword(password, newPassword) {

if (this.#pwdCheck(password)) {

this.#password = newPassword;

return true;

}

return this.#PWDERRMSG;

}

reanonymize(password) {

if (this.#pwdCheck(password)) {

this.displayName = this.#makeDisplayName();

return true;

}

return this.#PWDERRMSG;

}

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React/JavaScript: Tic-Tac-Toe Game (Play game)

This is a tic-tac-toe game, written in JavaScript and React.

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This is a tic-tac-toe game, written in JavaScript and React. It uses create-react-app to create a React application. The listing below is App.js.

App.js


import { useState } from 'react';

const WINNING_LINES = [
  [0, 1, 2],
  [3, 4, 5],
  [6, 7, 8],
  [0, 3, 6],
  [1, 4, 7],
  [2, 5, 8],
  [0, 4, 8],
  [2, 4, 6]
]

const PLAYER_MARKER = 'X';
const COMPUTER_MARKER = 'O';

// React components

// Game component, handles interaction between Board and ComputerStrength components
export default function Game() {
  const [strength, setStrength] = useState('Unbeatable');

  const handleRadio = (e) => {
    setStrength(e.target.value);
  }

  return (
    <div className="game">
      <div className="header"><h2>Tic-Tac-Toe</h2></div>
      <div className="game-board">
        <Board strength={strength} />
      </div>
      <div className="computer-strength-container">
        <ComputerStrength 
          className="strength" 
          value={'Computer Strength'} 
          strength={strength} 
          onRadioChange={(e) => handleRadio(e)}
        />
      </div>
    </div>
  )
}

// Board component
function Board({strength}) {
  const [squares, setSquares] = useState(Array(9).fill(null));

  let status;

  let winner = checkWinner(squares);

  if (winner) {
    status = `Winner: ${winner}`;
    showResetButton();
  } else if (squares.some(s => s === null)) {
    status = `Click a square ...`;
  } else {
    status = `Draw`;
    showResetButton();
  }

  const handleClick = i => {
    if (squares[i] || winner) return;

    const nextSquares = [...squares];
    nextSquares[i] = PLAYER_MARKER;
    winner = checkWinner(nextSquares);

    if (!winner) {
      nextSquares[getComputerMove(nextSquares, strength)] = COMPUTER_MARKER;
    }

    setSquares(nextSquares);
  }

  const handleReset = () => {
    setSquares(Array(9).fill(null));
    showResetButton(false);
  }

  return (
    <>
      <div className="board">
        <div className="status">{status}</div>
        <div className="board-row">
          <Square value={squares[0]} onSquareClick={() => handleClick(0)} />
          <Square value={squares[1]} onSquareClick={() => handleClick(1)} />
          <Square value={squares[2]} onSquareClick={() => handleClick(2)} />
        </div>
        <div className="board-row">
          <Square value={squares[3]} onSquareClick={() => handleClick(3)} />
          <Square value={squares[4]} onSquareClick={() => handleClick(4)} />
          <Square value={squares[5]} onSquareClick={() => handleClick(5)} />
        </div>
        <div className="board-row">
          <Square value={squares[6]} onSquareClick={() => handleClick(6)} />
          <Square value={squares[7]} onSquareClick={() => handleClick(7)} />
          <Square value={squares[8]} onSquareClick={() => handleClick(8)} />
        </div>
      </div>
      <div className="reset-container">
        <Button className="reset" value="New Game" onButtonClick={() => handleReset()} />
      </div>
    </>
  );

}

// Square component
function Square({value, onSquareClick}) {
  return (
    <button 
      className="square"
      onClick={onSquareClick}
    >
      {value}
    </button>
  );
}

// Generic button component, used for "New Game" button
function Button({value, onButtonClick}) {
  return (
    <button className="reset" onClick={onButtonClick}>{value}</button>
  )
}

// Computer strength component
function ComputerStrength({value, strength, onRadioChange}) {
  return ( 
    <div className="computer-strength">
      <p>{value}</p>
      <label>
        <input type="radio" 
          name="strength"
          value="Unbeatable"
          id="unbeatable"
          checked={strength === "Unbeatable"}
          onChange={onRadioChange}
        />
        Unbeatable
      </label>

      <label>
        <input type="radio" 
          name="strength"
          value="Decent"
          id="decent"
          checked={strength === "Decent"}
          onChange={onRadioChange}
        />
        Decent
      </label>

      <label>
        <input type="radio" 
          name="strength"
          value="Pitiful"
          id="pitiful"
          checked={strength === "Pitiful"}
          onChange={onRadioChange}
        />
        Pitiful
      </label>
    </div>
  )
}

// Helper functions

function showResetButton(show = true) {
  let resetStyle = document.querySelector('.reset-container').style
  resetStyle.visibility = show ? 'visible' : 'hidden';
}

function checkWinner(squares) {
  for (let line of WINNING_LINES) { 
    const lineVals = getLineVals(squares, line);
    if (lineVals[0] && new Set(lineVals).size === 1) return lineVals[0];
  }

  return null;
}

function getLineVals(squares, line) {
  return line.map(squareIndex => squares[squareIndex]);
}

// Computer move functions

// This is a port from Ruby. In the Ruby version, each 
// of these method calls would return a value from 0 through 8
// or nil. Since 0 is truthy in Ruby, the logical or is a good
// way to run through the methods until one returns a value 
// other than nil. But JS treats 0 as falsy, so the || construct 
// messes up if the function returns a 0 (top left corner move).
// Adding 1 to the return value and then subtracting it back
// out again works around this, although we have to also return
// undefined instead of null. Because null + 1 == 1 in JS, and  
// undefined + 1 == NaN. 
function getComputerMove(squares, strength) {
  if (strength === 'Pitiful') return randomMove(squares);

  let move =  
    takeComputerWin(squares) + 1 ||
    blockPlayerWin(squares) + 1 ||
    takeCenter(squares) + 1 || 
    (strength === 'Unbeatable' ? cornerPlay(squares) + 1 : NaN) ||
    randomMove(squares) + 1;

  return move - 1;
}

// Checks for winning computer move and returns it if there is one.
function takeComputerWin(squares) {
  for (let line of WINNING_LINES) {
    const lineVals = getLineVals(squares, line);
    const computerSquares = lineVals.filter(sq => sq === COMPUTER_MARKER);
    if (computerSquares.length === 2 && lineVals.includes(null)) {
      return line[lineVals.findIndex(val => val === null)];
    }
  }

  return undefined;
}

// Checks for winning player move and returns it if there is one 
// (computer will block the win).
function blockPlayerWin(squares) {
  for (let line of WINNING_LINES) {
    const lineVals = getLineVals(squares, line);
    const playerSquares = lineVals.filter(sq => sq === PLAYER_MARKER);
    if (playerSquares.length === 2 && lineVals.includes(null)) {
      return line[lineVals.findIndex(val => val === null)];
    }
  }

  return undefined;
}

// If no winning moves to take or block, take the center
function takeCenter(squares) {
  return !squares[4] ? 4 : undefined;
}

// Blocks various winning techniques involving corners. Comes into play
// if there are no winning moves to take or block, and center square is 
// taken.
//
// Not used unless computer strength is set to "Unbeatable."
//
// 1. If player takes two opposite corners, take any non-corner square.
// 2. If player takes squares 5 and 7 for first two moves (and computer
//    takes center for first move), take any corner but the top left one.
// 3. Otherwise, take first available corner (in the order 0, 2, 6, 8).
//
function cornerPlay(squares) {
  if (
    [squares[0], squares[8]].every(sq => sq === PLAYER_MARKER) ||
    [squares[2], squares[6]].every(sq => sq === PLAYER_MARKER)
  ) {
    return [1, 3, 5, 7].find(i => squares[i] === null);
  } else if (squares[5] === PLAYER_MARKER && squares[7] === PLAYER_MARKER) {
    return [2, 6, 8].find(i => squares[i] === null);
  } else {
    return [0, 2, 6, 8].find(i => squares[i] === null);
  }

  return undefined;
}

// Takes any available square. If none of the other functions returns a move,
// this is the default. Also, this is the only function called if computer
// strength is set to "Pitiful."
function randomMove(squares) {
  const openSquares = [];
  squares.forEach((e, i) => {
    if (e === null) openSquares.push(i);
  });
  return openSquares[Math.floor(Math.random() * openSquares.length)];
}

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import { useState } from 'react';

const WINNING_LINES = [

[0, 1, 2],

[3, 4, 5],

[6, 7, 8],

[0, 3, 6],

[1, 4, 7],

[2, 5, 8],

[0, 4, 8],

[2, 4, 6]

]

const PLAYER_MARKER = 'X';

const COMPUTER_MARKER = 'O';

// React components

// Game component, handles interaction between Board and ComputerStrength components

export default function Game() {

const [strength, setStrength] = useState('Unbeatable');

const handleRadio = (e) => {

setStrength(e.target.value);

}

return (

</div>

<ComputerStrength

className="strength"

value={'Computer Strength'}

strength={strength}

onRadioChange={(e) => handleRadio(e)}

</div>

)

}

// Board component

function Board({strength}) {

const [squares, setSquares] = useState(Array(9).fill(null));

let status;

let winner = checkWinner(squares);

if (winner) {

status = `Winner: ${winner}`;

showResetButton();

} else if (squares.some(s => s === null)) {

status = `Click a square ...`;

} else {

status = `Draw`;

showResetButton();

}

const handleClick = i => {

if (squares[i] || winner) return;

const nextSquares = [...squares];

nextSquares[i] = PLAYER_MARKER;

winner = checkWinner(nextSquares);

if (!winner) {

nextSquares[getComputerMove(nextSquares, strength)] = COMPUTER_MARKER;

}

setSquares(nextSquares);

}

const handleReset = () => {

setSquares(Array(9).fill(null));

showResetButton(false);

}

return (

<div className="status">{status}</div>

<Square value={squares[0]} onSquareClick={() => handleClick(0)} />

<Square value={squares[1]} onSquareClick={() => handleClick(1)} />

<Square value={squares[2]} onSquareClick={() => handleClick(2)} />

</div>

<Square value={squares[3]} onSquareClick={() => handleClick(3)} />

<Square value={squares[4]} onSquareClick={() => handleClick(4)} />

<Square value={squares[5]} onSquareClick={() => handleClick(5)} />

</div>

<Square value={squares[6]} onSquareClick={() => handleClick(6)} />

<Square value={squares[7]} onSquareClick={() => handleClick(7)} />

<Square value={squares[8]} onSquareClick={() => handleClick(8)} />

</div>

<Button className="reset" value="New Game" onButtonClick={() => handleReset()} />

</div>

</>

);

}

// Square component

function Square({value, onSquareClick}) {

return (

<button

className="square"

onClick={onSquareClick}

{value}

</button>

);

}

// Generic button component, used for "New Game" button

function Button({value, onButtonClick}) {

return (

<button className="reset" onClick={onButtonClick}>{value}</button>

)

}

// Computer strength component

function ComputerStrength({value, strength, onRadioChange}) {

return (

<p>{value}</p>

<label>

<input type="radio"

name="strength"

value="Unbeatable"

id="unbeatable"

checked={strength === "Unbeatable"}

onChange={onRadioChange}

Unbeatable

</label>

<label>

<input type="radio"

name="strength"

value="Decent"

id="decent"

checked={strength === "Decent"}

onChange={onRadioChange}

Decent

</label>

<label>

<input type="radio"

name="strength"

value="Pitiful"

id="pitiful"

checked={strength === "Pitiful"}

onChange={onRadioChange}

Pitiful

</label>

</div>

)

}

// Helper functions

function showResetButton(show = true) {

let resetStyle = document.querySelector('.reset-container').style

resetStyle.visibility = show ? 'visible' : 'hidden';

}

function checkWinner(squares) {

for (let line of WINNING_LINES) {

const lineVals = getLineVals(squares, line);

if (lineVals[0] && new Set(lineVals).size === 1) return lineVals[0];

}

return null;

}

function getLineVals(squares, line) {

return line.map(squareIndex => squares[squareIndex]);

}

// Computer move functions

// This is a port from Ruby. In the Ruby version, each

// of these method calls would return a value from 0 through 8

// or nil. Since 0 is truthy in Ruby, the logical or is a good

// way to run through the methods until one returns a value

// other than nil. But JS treats 0 as falsy, so the || construct

// messes up if the function returns a 0 (top left corner move).

// Adding 1 to the return value and then subtracting it back

// out again works around this, although we have to also return

// undefined instead of null. Because null + 1 == 1 in JS, and

// undefined + 1 == NaN.

function getComputerMove(squares, strength) {

if (strength === 'Pitiful') return randomMove(squares);

let move =

takeComputerWin(squares) + 1 ||

blockPlayerWin(squares) + 1 ||

takeCenter(squares) + 1 ||

(strength === 'Unbeatable' ? cornerPlay(squares) + 1 : NaN) ||

randomMove(squares) + 1;

return move - 1;

}

// Checks for winning computer move and returns it if there is one.

function takeComputerWin(squares) {

for (let line of WINNING_LINES) {

const lineVals = getLineVals(squares, line);

const computerSquares = lineVals.filter(sq => sq === COMPUTER_MARKER);

if (computerSquares.length === 2 && lineVals.includes(null)) {

return line[lineVals.findIndex(val => val === null)];

}

return undefined;

}

// Checks for winning player move and returns it if there is one

// (computer will block the win).

function blockPlayerWin(squares) {

for (let line of WINNING_LINES) {

const lineVals = getLineVals(squares, line);

const playerSquares = lineVals.filter(sq => sq === PLAYER_MARKER);

if (playerSquares.length === 2 && lineVals.includes(null)) {

return line[lineVals.findIndex(val => val === null)];

}

return undefined;

}

// If no winning moves to take or block, take the center

function takeCenter(squares) {

return !squares[4] ? 4 : undefined;

}

// Blocks various winning techniques involving corners. Comes into play

// if there are no winning moves to take or block, and center square is

// taken.

// Not used unless computer strength is set to "Unbeatable."

// 1. If player takes two opposite corners, take any non-corner square.

// 2. If player takes squares 5 and 7 for first two moves (and computer

// takes center for first move), take any corner but the top left one.

// 3. Otherwise, take first available corner (in the order 0, 2, 6, 8).

function cornerPlay(squares) {

if (

[squares[0], squares[8]].every(sq => sq === PLAYER_MARKER) ||

[squares[2], squares[6]].every(sq => sq === PLAYER_MARKER)

) {

return [1, 3, 5, 7].find(i => squares[i] === null);

} else if (squares[5] === PLAYER_MARKER && squares[7] === PLAYER_MARKER) {

return [2, 6, 8].find(i => squares[i] === null);

} else {

return [0, 2, 6, 8].find(i => squares[i] === null);

}

return undefined;

}

// Takes any available square. If none of the other functions returns a move,

// this is the default. Also, this is the only function called if computer

// strength is set to "Pitiful."

function randomMove(squares) {

const openSquares = [];

squares.forEach((e, i) => {

if (e === null) openSquares.push(i);

});

return openSquares[Math.floor(Math.random() * openSquares.length)];

}

Collapse

Ruby: Blackjack Game

This is a terminal-based version of Blackjack, written in Ruby.

Expand

This is a terminal-based version of Blackjack, written in Ruby.


# Application-wide constants
module App
  BUST_VALUE = 21
  DEALER_STAND_VALUE = 17
  SCREEN_WIDTH = 60
  HEADER = "n#{'Rodes Black Jack'.center(SCREEN_WIDTH)}nn"
  SLEEP_TIME = 1 # How long to wait between dealer cards dealt, etc.
end

module Utilities
  require 'io/console'

  KEY_ONLY = true # Key only or key + enter

  def getchar
    if KEY_ONLY
      char = STDIN.getch
      if char == "u0003" # Ctrl-C
        puts
        exit
      end
    else
      char = gets.chomp[0]
    end
    char
  end

  def cls
    system('clear') || system('cls')
  end

  def say(message, new_lines = 0)
    print message.to_s
    print "n" * new_lines
  end

  # This disables keyboard input while #sleep is running. Necessary in
  # key_only mode because otherwise key inputs will echo on the screen.
  def wait(for_time)
    system('stty raw -echo')
    sleep for_time
    system('stty -raw echo')
  end

  # Assumes "space plus nn" for new paragraph.
  def word_wrap(str, width = App::SCREEN_WIDTH)
    char_count = 0
    lastchar = str.end_with?(' ') ? ' ' : ''
    str.split(/ /).each do |word|
      char_count += word.size + 1
      if char_count > width
        word.prepend("n") unless word.start_with?("nn")
        char_count = word.size + 1
      end
      char_count = word.size - 1 if word.include?("nn")
    end.join(' ') << lastchar
  end
end

class Deck
  # Used for calculating score
  CARD_VALUES = {
    '2'  => 2,
    '3'  => 3,
    '4'  => 4,
    '5'  => 5,
    '6'  => 6,
    '7'  => 7,
    '8'  => 8,
    '9'  => 9,
    '10' => 10,
    'J'  => 10,
    'Q'  => 10,
    'K'  => 10,
    'A'  => 11
  }.freeze

  RANKS = %w(2 3 4 5 6 7 8 9 10 J Q K A).freeze

  # UTF codes for suit symbols
  SUITS = ["u2660", "u2661", "u2662", "u2663"].freeze

  attr_reader :cards

  def initialize
    new_deck
  end

  def new_deck
    @cards = RANKS.product(SUITS).shuffle
  end
end

# This "Player" class implements functionality that the user/player and dealer have in common. Both the user and 
# dealer inherit this class; I opted for "Gambler" for the user/player class.
class Player
  include Utilities
  attr_reader :hand, :score

  def initialize(deck)
    @deck = deck
  end

  def new_hand
    @hand = []
    2.times { hit }
    calc_score
  end

  def calc_score
    total = 0

    hand.each do |card|
      total += Deck::CARD_VALUES[card[0]]
    end

    aces = hand.count { |a| a[0] == 'A' }
    while total > App::BUST_VALUE && aces > 0
      total -= 10
      aces -= 1
    end

    @score = total
  end

  private

  def hit
    @hand.push(@deck.cards.pop)
  end
end

class Gambler < Player
  attr_accessor :cash
  attr_reader :name

  def initialize(deck, cash)
    super(deck)
    @cash = cash
    @name = choose_name
  end

  def turn(table)
    loop do
      play = play_decision

      if play == 'h'
        hit
        calc_score
        table.show
      end

      break if score > App::BUST_VALUE || play == 's'
    end
  end

  private

  def choose_name
    first_time = true
    the_name = ''
    cls
    welcome = "nWelcome to Rodes Black Jack! "
    loop do
      say word_wrap("#{first_time ? welcome + 'W' : 'So, w'}hat's your name? ")
      the_name = gets.chomp
      break unless the_name.delete(' ').empty?
      first_time = false
      say word_wrap("Sorry, only The Man With No Name is allowed to play " 
        "without a name. "), 1
    end
    puts
    the_name.split.map(&:capitalize).join(' ')
  end

  def play_decision
    loop do
      say 'Hit or stand (H or S)? '
      play = getchar.downcase
      return play if 'hs'.chars.include?(play)
      say "nInvalid value. Please try again.", 1
    end
  end
end

class Dealer < Player
  attr_accessor :hide_hand

  def initialize(deck)
    super
    @hide_hand = true
  end

  def turn(table)
    @hide_hand = false
    wait App::SLEEP_TIME

    loop do
      table.show
      wait App::SLEEP_TIME
      break if score >= App::DEALER_STAND_VALUE
      hit
      calc_score
    end
  end
end

# Displays the table. The table shows the header, the player's and dealer's
# hands, the scores, and the player's cash.
class Table
  include Utilities

  def initialize(dealer, gambler)
    @dealer = dealer
    @gambler = gambler
  end

  def show
    cls
    print "#{App::HEADER}" 
          "#{'Dealer'.center(App::SCREEN_WIDTH)}n" 
          "#{create_hand_view(@dealer).center(App::SCREEN_WIDTH)}nn" 
          "#{Deck::SUITS.join('    ').center(App::SCREEN_WIDTH)}nn" 
          "#{create_hand_view(@gambler).center(App::SCREEN_WIDTH)}n" 
          "#{@gambler.name.center(App::SCREEN_WIDTH)}nn" 
          "Player score: #{@gambler.score}n" 
          "Dealer score: #{@dealer.hide_hand ? '??' : @dealer.score}nn" 
          "Player cash:  $#{@gambler.cash}nn"
  end

  private

  def create_hand_view(player)
    return player.hand[0].join if player.class == Dealer && player.hide_hand
    hand_view = ''
    player.hand.each_with_index do |card, i|
      hand_view << card.join
      hand_view << '  ' unless i + 1 == player.hand.size
    end
    hand_view
  end
end

# Handles a single round of play, from dealing the hands to figuring the result.
class Round
  include Utilities

  NATURAL_YES = 'Got one!'
  NATURAL_NO = 'Not this time.'

  attr_reader :result

  def initialize(dealer, gambler, table)
    @dealer = dealer
    @gambler = gambler
    @table = table
    @result = nil
  end

  def play
    @gambler.new_hand
    @dealer.new_hand
    @table.show
    dealer_check_natural
    @table.show
    @result = calc_natural_result
    return unless @result.nil?
    @gambler.turn(@table)
    @result = calc_result
    return unless @result.nil?
    @dealer.turn(@table)
    @result = calc_result
  end

  private

  def calc_natural_result
    return :natural_push    if @dealer.score == App::BUST_VALUE &&
                               @gambler.score == App::BUST_VALUE
    return :dealer_natural  if @dealer.score == App::BUST_VALUE
    return :gambler_natural if @gambler.score == App::BUST_VALUE
    nil
  end

  def calc_result
    return :gambler_bust if @gambler.score > App::BUST_VALUE
    return nil if @dealer.hide_hand
    return :dealer_bust if @dealer.score > App::BUST_VALUE
    case @gambler.score <=> @dealer.score
    when 1
      :gambler
    when -1
      :dealer
    else
      :push
    end
  end

  def dealer_check_natural
    return unless Deck::CARD_VALUES[@dealer.hand[0][0]] >= 10
    print word_wrap("Dealer is checking for a natural #{App::BUST_VALUE} ... ")
    wait App::SLEEP_TIME
    print "#{@dealer.score == App::BUST_VALUE ? NATURAL_YES : NATURAL_NO}n"
    wait App::SLEEP_TIME
  end
end

class BlackJack
  include Utilities

  BET = 1
  NATURAL_MULTIPLIER = 10

  APPLY_BET = {
    gambler_natural: BET * NATURAL_MULTIPLIER,
    dealer_bust:     BET,
    gambler:         BET,
    natural_push:    0,
    push:            0,
    dealer:          -BET,
    gambler_bust:    -BET,
    dealer_natural:  -BET
  }.freeze

  GAMBLER_STAKE = 50

  HAND_RESULT_PROMPT = {
    gambler_natural: "Player holds a natural #{App::BUST_VALUE}! Player " 
                     "wins $#{APPLY_BET[:gambler_natural]}.",
    dealer_bust:     'Dealer busted. Player wins.',
    gambler:         'Player wins.',
    natural_push:    "Dealer and player both hold a natural " 
                     "#{App::BUST_VALUE}! That's a push.",
    push:            'Push.',
    dealer:          'Dealer wins.',
    gambler_bust:    'Player busted. Dealer wins.',
    dealer_natural:  "Dealer holds a natural #{App::BUST_VALUE}. Dealer wins."
  }.freeze

  # Increasing App::BUST_VALUE requires that NEW_DECK_COUNT be increased as
  # well. To avoid the possibility of an error from trying to deal from an
  # empty deck, NEW_DECK_COUNT has to be at least as high as the maximum
  # possible number of cards for both hands.
  NEW_DECK_COUNT = 18

  SPACE = ' '

  def initialize
    @deck = Deck.new
    @dealer = Dealer.new(@deck)
    @gambler = Gambler.new(@deck, GAMBLER_STAKE)
    @table = Table.new(@dealer, @gambler)
  end

  def play
    show_opening_screen
    loop do
      round = Round.new(@dealer, @gambler, @table)
      round.play
      @dealer.hide_hand = false
      @gambler.cash += APPLY_BET[round.result]
      @table.show
      say HAND_RESULT_PROMPT[round.result], 2
      break unless play_again?
      reset
    end
    show_closing_screen
  end

  private

  def closing_screen_message
    <<~BLOCK
      Thank you for playing at Rodes Black Jack, 
      #{@gambler.name}!#{SPACE}

      #{closing_screen_message_which}
    BLOCK
  end

  def closing_screen_message_which
    case @gambler.cash <=> GAMBLER_STAKE
    when -1 then  closing_screen_message_lose
    when  1 then  closing_screen_message_win
    else          "You have broken even. Oh well, maybe next time.n"
    end
  end

  def closing_screen_message_lose
    <<~BLOCK
      You have lost $#{GAMBLER_STAKE - @gambler.cash}.#{SPACE}

      But not to worry. Just spend a year washing dishes in our kitchen and 
      we'll call it even.#{SPACE}

      See you tomorrow at 5 a.m. Don't be late!#{SPACE}
    BLOCK
  end

  def closing_screen_message_win
    <<~BLOCK
      You have won $#{@gambler.cash - GAMBLER_STAKE}. We'll be keeping the 
      money, of course. After all, it was ours to begin with.#{SPACE}

      Stop back and see us again!#{SPACE}
    BLOCK
  end

  def opening_screen_message
    <<~BLOCK
      Welcome #{@gambler.name}!

      You have been awarded a gambling spree at Rodes Black Jack, 
      our favorite casino!#{SPACE}

      Black Jack is the game we play ... sort of. No doubling down, and no 
      splitting pairs.#{SPACE}

      You have $#{GAMBLER_STAKE} to play with. Bet is $#{BET} per hand.#{SPACE}

      Black Jack (natural #{App::BUST_VALUE}) pays #{NATURAL_MULTIPLIER} 
      to 1. Good luck!#{SPACE}

      Please hit #{KEY_ONLY ? 'any key' : '"Enter"'} when you are ready to 
      begin:#{SPACE}
    BLOCK
  end

  def play_again?
    say word_wrap("Please #{KEY_ONLY ? 'hit' : 'enter'} Q to quit, or " 
    'anything else to play again: ')
    char = getchar
    print "n"
    return false if !char.nil? && char.casecmp('q').zero?
    true
  end

  def reset
    @dealer.hide_hand = true
    return if @deck.cards.count > NEW_DECK_COUNT
    say 'Reshuffling ... ', 1
    wait App::SLEEP_TIME * 2
    @deck.new_deck
  end

  def show_closing_screen
    cls
    print App::HEADER
    print word_wrap(closing_screen_message)
    print "Please hit #{KEY_ONLY ? 'any key' : '"Enter"'} to leave ... "
    getchar
    print "Bye now.nn"
  end

  def show_opening_screen
    cls
    print App::HEADER
    print word_wrap(opening_screen_message)
    getchar
  end
end

game = BlackJack.new
game.play

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# Application-wide constants

module App

BUST_VALUE = 21

DEALER_STAND_VALUE = 17

SCREEN_WIDTH = 60

HEADER = "n#{'Rodes Black Jack'.center(SCREEN_WIDTH)}nn"

SLEEP_TIME = 1 # How long to wait between dealer cards dealt, etc.

end

module Utilities

require 'io/console'

KEY_ONLY = true # Key only or key + enter

def getchar

if KEY_ONLY

char = STDIN.getch

if char == "u0003" # Ctrl-C

puts

exit

end

else

char = gets.chomp[0]

end

char

end

def cls

system('clear') || system('cls')

end

def say(message, new_lines = 0)

print message.to_s

print "n" * new_lines

end

# This disables keyboard input while #sleep is running. Necessary in

# key_only mode because otherwise key inputs will echo on the screen.

def wait(for_time)

system('stty raw -echo')

sleep for_time

system('stty -raw echo')

end

# Assumes "space plus nn" for new paragraph.

def word_wrap(str, width = App::SCREEN_WIDTH)

char_count = 0

lastchar = str.end_with?(' ') ? ' ' : ''

str.split(/ /).each do |word|

char_count += word.size + 1

if char_count > width

word.prepend("n") unless word.start_with?("nn")

char_count = word.size + 1

end

char_count = word.size - 1 if word.include?("nn")

end.join(' ') << lastchar

end

class Deck

# Used for calculating score

CARD_VALUES = {

'2' => 2,

'3' => 3,

'4' => 4,

'5' => 5,

'6' => 6,

'7' => 7,

'8' => 8,

'9' => 9,

'10' => 10,

'J' => 10,

'Q' => 10,

'K' => 10,

'A' => 11

}.freeze

RANKS = %w(2 3 4 5 6 7 8 9 10 J Q K A).freeze

# UTF codes for suit symbols

SUITS = ["u2660", "u2661", "u2662", "u2663"].freeze

attr_reader :cards

def initialize

new_deck

end

def new_deck

@cards = RANKS.product(SUITS).shuffle

end

# This "Player" class implements functionality that the user/player and dealer have in common. Both the user and

# dealer inherit this class; I opted for "Gambler" for the user/player class.

class Player

include Utilities

attr_reader :hand, :score

def initialize(deck)

@deck = deck

end

def new_hand

@hand = []

2.times { hit }

calc_score

end

def calc_score

total = 0

hand.each do |card|

total += Deck::CARD_VALUES[card[0]]

end

aces = hand.count { |a| a[0] == 'A' }

while total > App::BUST_VALUE && aces > 0

total -= 10

aces -= 1

end

@score = total

end

private

def hit

@hand.push(@deck.cards.pop)

end

class Gambler < Player

attr_accessor :cash

attr_reader :name

def initialize(deck, cash)

super(deck)

@cash = cash

@name = choose_name

end

def turn(table)

loop do

play = play_decision

if play == 'h'

hit

calc_score

table.show

end

break if score > App::BUST_VALUE || play == 's'

end

private

def choose_name

first_time = true

the_name = ''

cls

welcome = "nWelcome to Rodes Black Jack! "

loop do

say word_wrap("#{first_time ? welcome + 'W' : 'So, w'}hat's your name? ")

the_name = gets.chomp

break unless the_name.delete(' ').empty?

first_time = false

say word_wrap("Sorry, only The Man With No Name is allowed to play "

"without a name. "), 1

end

puts

the_name.split.map(&:capitalize).join(' ')

end

def play_decision

loop do

say 'Hit or stand (H or S)? '

play = getchar.downcase

return play if 'hs'.chars.include?(play)

say "nInvalid value. Please try again.", 1

end

class Dealer < Player

attr_accessor :hide_hand

def initialize(deck)

super

@hide_hand = true

end

def turn(table)

@hide_hand = false

wait App::SLEEP_TIME

loop do

table.show

wait App::SLEEP_TIME

break if score >= App::DEALER_STAND_VALUE

hit

calc_score

end

# Displays the table. The table shows the header, the player's and dealer's

# hands, the scores, and the player's cash.

class Table

include Utilities

def initialize(dealer, gambler)

@dealer = dealer

@gambler = gambler

end

def show

cls

print "#{App::HEADER}"

"#{'Dealer'.center(App::SCREEN_WIDTH)}n"

"#{create_hand_view(@dealer).center(App::SCREEN_WIDTH)}nn"

"#{Deck::SUITS.join(' ').center(App::SCREEN_WIDTH)}nn"

"#{create_hand_view(@gambler).center(App::SCREEN_WIDTH)}n"

"#{@gambler.name.center(App::SCREEN_WIDTH)}nn"

"Player score: #{@gambler.score}n"

"Dealer score: #{@dealer.hide_hand ? '??' : @dealer.score}nn"

"Player cash: $#{@gambler.cash}nn"

end

private

def create_hand_view(player)

return player.hand[0].join if player.class == Dealer && player.hide_hand

hand_view = ''

player.hand.each_with_index do |card, i|

hand_view << card.join

hand_view << ' ' unless i + 1 == player.hand.size

end

hand_view

end

# Handles a single round of play, from dealing the hands to figuring the result.

class Round

include Utilities

NATURAL_YES = 'Got one!'

NATURAL_NO = 'Not this time.'

attr_reader :result

def initialize(dealer, gambler, table)

@dealer = dealer

@gambler = gambler

@table = table

@result = nil

end

def play

@gambler.new_hand

@dealer.new_hand

@table.show

dealer_check_natural

@table.show

@result = calc_natural_result

return unless @result.nil?

@gambler.turn(@table)

@result = calc_result

return unless @result.nil?

@dealer.turn(@table)

@result = calc_result

end

private

def calc_natural_result

return :natural_push if @dealer.score == App::BUST_VALUE &&

@gambler.score == App::BUST_VALUE

return :dealer_natural if @dealer.score == App::BUST_VALUE

return :gambler_natural if @gambler.score == App::BUST_VALUE

nil

end

def calc_result

return :gambler_bust if @gambler.score > App::BUST_VALUE

return nil if @dealer.hide_hand

return :dealer_bust if @dealer.score > App::BUST_VALUE

case @gambler.score <=> @dealer.score

when 1

:gambler

when -1

:dealer

else

:push

end

def dealer_check_natural

return unless Deck::CARD_VALUES[@dealer.hand[0][0]] >= 10

print word_wrap("Dealer is checking for a natural #{App::BUST_VALUE} ... ")

wait App::SLEEP_TIME

print "#{@dealer.score == App::BUST_VALUE ? NATURAL_YES : NATURAL_NO}n"

wait App::SLEEP_TIME

end

class BlackJack

include Utilities

BET = 1

NATURAL_MULTIPLIER = 10

APPLY_BET = {

gambler_natural: BET * NATURAL_MULTIPLIER,

dealer_bust: BET,

gambler: BET,

natural_push: 0,

push: 0,

dealer: -BET,

gambler_bust: -BET,

dealer_natural: -BET

}.freeze

GAMBLER_STAKE = 50

HAND_RESULT_PROMPT = {

gambler_natural: "Player holds a natural #{App::BUST_VALUE}! Player "

"wins $#{APPLY_BET[:gambler_natural]}.",

dealer_bust: 'Dealer busted. Player wins.',

gambler: 'Player wins.',

natural_push: "Dealer and player both hold a natural "

"#{App::BUST_VALUE}! That's a push.",

push: 'Push.',

dealer: 'Dealer wins.',

gambler_bust: 'Player busted. Dealer wins.',

dealer_natural: "Dealer holds a natural #{App::BUST_VALUE}. Dealer wins."

}.freeze

# Increasing App::BUST_VALUE requires that NEW_DECK_COUNT be increased as

# well. To avoid the possibility of an error from trying to deal from an

# empty deck, NEW_DECK_COUNT has to be at least as high as the maximum

# possible number of cards for both hands.

NEW_DECK_COUNT = 18

SPACE = ' '

def initialize

@deck = Deck.new

@dealer = Dealer.new(@deck)

@gambler = Gambler.new(@deck, GAMBLER_STAKE)

@table = Table.new(@dealer, @gambler)

end

def play

show_opening_screen

loop do

round = Round.new(@dealer, @gambler, @table)

round.play

@dealer.hide_hand = false

@gambler.cash += APPLY_BET[round.result]

@table.show

say HAND_RESULT_PROMPT[round.result], 2

break unless play_again?

reset

end

show_closing_screen

end

private

def closing_screen_message

<<~BLOCK

Thank you for playing at Rodes Black Jack,

#{@gambler.name}!#{SPACE}

#{closing_screen_message_which}

BLOCK

end

def closing_screen_message_which

case @gambler.cash <=> GAMBLER_STAKE

when -1 then closing_screen_message_lose

when 1 then closing_screen_message_win

else "You have broken even. Oh well, maybe next time.n"

end

def closing_screen_message_lose

<<~BLOCK

You have lost $#{GAMBLER_STAKE - @gambler.cash}.#{SPACE}

But not to worry. Just spend a year washing dishes in our kitchen and

we'll call it even.#{SPACE}

See you tomorrow at 5 a.m. Don't be late!#{SPACE}

BLOCK

end

def closing_screen_message_win

<<~BLOCK

You have won $#{@gambler.cash - GAMBLER_STAKE}. We'll be keeping the

money, of course. After all, it was ours to begin with.#{SPACE}

Stop back and see us again!#{SPACE}

BLOCK

end

def opening_screen_message

<<~BLOCK

Welcome #{@gambler.name}!

You have been awarded a gambling spree at Rodes Black Jack,

our favorite casino!#{SPACE}

Black Jack is the game we play ... sort of. No doubling down, and no

splitting pairs.#{SPACE}

You have $#{GAMBLER_STAKE} to play with. Bet is $#{BET} per hand.#{SPACE}

Black Jack (natural #{App::BUST_VALUE}) pays #{NATURAL_MULTIPLIER}

to 1. Good luck!#{SPACE}

Please hit #{KEY_ONLY ? 'any key' : '"Enter"'} when you are ready to

begin:#{SPACE}

BLOCK

end

def play_again?

say word_wrap("Please #{KEY_ONLY ? 'hit' : 'enter'} Q to quit, or "

'anything else to play again: ')

char = getchar

print "n"

return false if !char.nil? && char.casecmp('q').zero?

true

end

def reset

@dealer.hide_hand = true

return if @deck.cards.count > NEW_DECK_COUNT

say 'Reshuffling ... ', 1

wait App::SLEEP_TIME * 2

@deck.new_deck

end

def show_closing_screen

cls

print App::HEADER

print word_wrap(closing_screen_message)

print "Please hit #{KEY_ONLY ? 'any key' : '"Enter"'} to leave ... "

getchar

print "Bye now.nn"

end

def show_opening_screen

cls

print App::HEADER

print word_wrap(opening_screen_message)

getchar

end

game = BlackJack.new

game.play

Collapse

Python: Blackjack Game

This is a terminal-based version of Blackjack, written in Python.

Expand

This is a port of the Ruby blackjack game to Python.


from itertools import product
import random
import os
import time

class App:
    BUST_VALUE = 21
    DEALER_STAND_VALUE = 17
    SCREEN_WIDTH = 60
    HEADER = f"n{'Rodes Black Jack'.center(SCREEN_WIDTH)}n"
    SLEEP_TIME = 1 # How long to wait between dealer cards dealt, etc.

class UtilsMixin:
    def cls(self):
        os.system('clear||cls')

    def say(self, message, new_lines=0):
        print(message)
        print("n" * new_lines)

    def wait(self, interval):
        time.sleep(interval)

    def sign(self, val1, val2):
        difference = val1 - val2
        if difference > 0:
            return 1
        elif difference < 0:
            return -1
        else:
            return 0

class Deck:
    _CARD_VALUES = { 
      '2': 2,
      '3': 3,
      '4': 4,
      '5': 5,
      '6': 6,
      '7': 7,
      '8': 8,
      '9': 9,
      '10': 10,
      'J': 10,
      'Q': 10,
      'K': 10,
      'A': 11
    }

    _RANKS = '2 3 4 5 6 7 8 9 10 J Q K A'.split()
    _SUITS = ["u2660", "u2661", "u2662", "u2663"]

    def __init__(self):
        self.new_deck()

    def new_deck(self):
        cards = [*product(Deck._RANKS, Deck._SUITS)]
        random.shuffle(cards)
        self.cards = cards

class Player(UtilsMixin):
    def __init__(self, deck):
        self.deck = deck
        self.hand = None

    def new_hand(self):
        self.hand = []
        for _ in range(2):
            self.hit()
        self.calc_score()

    def calc_score(self):
        total = 0
        for card in self.hand:
            total += Deck._CARD_VALUES[card[0]]
        aces = sum(1 for val in self.hand if val[0] == 'A')
        while total > App.BUST_VALUE and aces > 0:
            total -= 10
            aces -= 1
        self.score = total

    def hit(self):
        self.hand.append(self.deck.cards.pop())

class Gambler(Player):
    def __init__(self, deck, cash):
        super().__init__(deck)
        self.cash = cash
        self.name = self.choose_name()

    def turn(self, table):
        while True:
            play = self.play_decision()

            if play == 'h':
                self.hit()
                self.calc_score()
                table.show()

            if self.score > App.BUST_VALUE or play == 's':
                break

    def choose_name(self):
        first_time = True
        the_name = ''
        self.cls()
        welcome = "nWelcome to Rodes Black Jack! "

        while True:
            the_name = input(f"{welcome + 'W' if first_time else 'So, w'}hat's your name? ")
            if the_name.replace(' ', '') == '':
                first_time = False
                self.say("nSorry, only The Man With No Name is allowed to play without a name.")
            else:
                break
        
        return the_name

    def play_decision(self):
        while True:
            play = input('Hit or stand (H or S)? ').lower()
            if play in 'hs':
                return play
            else:
                self.say("nInvalid value. Please try again.", 1)

class Dealer(Player):
    def __init__(self, deck):
        super().__init__(deck)
        self.hide_hand = True

    def turn(self, table):
        self.hide_hand = False
        self.wait(App.SLEEP_TIME)

        while True:
            table.show()
            self.wait(App.SLEEP_TIME)

            if self.score >= App.DEALER_STAND_VALUE:
                break
            else:
                self.hit()

            self.calc_score()

class Table(UtilsMixin):
    def __init__(self, dealer, gambler):
        self.dealer = dealer
        self.gambler = gambler

    def show(self):
        self.cls()
        print(f"""
{App.HEADER}
{'Dealer'.center(App.SCREEN_WIDTH)}
{self.create_hand_view(self.dealer).center(App.SCREEN_WIDTH)}

{'    '.join(Deck._SUITS).center(App.SCREEN_WIDTH)}

{self.create_hand_view(self.gambler).center(App.SCREEN_WIDTH)}
{self.gambler.name.center(App.SCREEN_WIDTH)}

Player score: {self.gambler.score}
Dealer score: {'??' if self.dealer.hide_hand else self.dealer.score}
Player cash:  ${self.gambler.cash}
        """)

    def create_hand_view(self, player):
        if type(player).__name__ == 'Dealer' and player.hide_hand:
            return ''.join(player.hand[0])

        return '  '.join(''.join(h) for h in player.hand)

class Round(UtilsMixin):
    NATURAL_YES = 'Got one!'
    NATURAL_NO = 'Not this time.'
    
    def __init__(self, dealer, gambler, table):
        self.dealer = dealer
        self.gambler = gambler
        self.table = table
        self.result = None

    def play(self):
        self.gambler.new_hand()
        self.dealer.new_hand()
        self.table.show()
        self.dealer_check_natural()
        self.result = self.calc_natural_result()
        if self.result != None:
            self.dealer.hide_hand = False
            self.table.show()
            return
        self.table.show()

        self.gambler.turn(self.table)
        self.result = self.calc_result()
        if self.result != None:
            return

        self.dealer.turn(self.table)
        self.result = self.calc_result()

    def calc_natural_result(self):
        if (self. dealer.score == App.BUST_VALUE 
            and self.gambler.score == App.BUST_VALUE):
            return 'natural_push'
        if self. dealer.score == App.BUST_VALUE:
            return 'dealer_natural' 
        if self. gambler.score == App.BUST_VALUE:
            return 'gambler_natural'
        return None

    def calc_result(self):
        if self.gambler.score > App.BUST_VALUE:
            return 'gambler_bust'
        if self.dealer.hide_hand:
            return None
        if self.dealer.score > App.BUST_VALUE:
            return 'dealer_bust' 
        return ['push', 'gambler', 'dealer'][self.sign(self.gambler.score, self.dealer.score)]

    def dealer_check_natural(self):
        if Deck._CARD_VALUES[self.dealer.hand[0][0]] < 10:
            return
        print(f"Dealer is checking for a natural {App.BUST_VALUE} ... ")
        self.wait(App.SLEEP_TIME)
        print(f"{self.NATURAL_YES if self.dealer.score == App.BUST_VALUE else self.NATURAL_NO}n")
        self.wait(App.SLEEP_TIME)

class BlackJack(UtilsMixin):
    BET = 1
    NATURAL_MULTIPLIER = 10
    GAMBLER_STAKE = 50
    SPACE = ' '
    # Increasing App.BUST_VALUE requires that NEW_DECK_COUNT be increased as
    # well. To avoid the possibility of an error from trying to deal from an
    # empty deck, NEW_DECK_COUNT has to be at least as high as the maximum
    # possible number of cards for both hands.
    NEW_DECK_COUNT = 18

    APPLY_BET = {
        'gambler_natural': BET * NATURAL_MULTIPLIER,
        'dealer_bust':     BET,
        'gambler':         BET,
        'natural_push':    0,
        'push':            0,
        'dealer':          -BET,
        'gambler_bust':    -BET,
        'dealer_natural':  -BET
    }

    HAND_RESULT_PROMPT = {
        'gambler_natural': f"Player holds a natural {App.BUST_VALUE}! Player wins ${APPLY_BET['gambler_natural']}.",
        'dealer_bust':     'Dealer busted. Player wins.',
        'gambler':         'Player wins.',
        'natural_push':    f"Dealer and player both hold a natural {App.BUST_VALUE}! That's a push.",
        'push':            'Push.',
        'dealer':          'Dealer wins.',
        'gambler_bust':    'Player busted. Dealer wins.',
        'dealer_natural':  f"Dealer holds a natural {App.BUST_VALUE}. Dealer wins."
    }

    def __init__(self):
        self.deck = Deck()
        self.dealer = Dealer(self.deck)
        self.gambler = Gambler(self.deck, self.GAMBLER_STAKE)
        self.table = Table(self.dealer, self.gambler)

    def play(self):
        self.show_opening_screen()
        while True:
            round = Round(self.dealer, self.gambler, self.table)
            round.play()
            self.dealer.hide_hand = False
            self.gambler.cash += self.APPLY_BET[round.result]
            self.table.show()
            self.say(self.HAND_RESULT_PROMPT[round.result], 2)
            if not self.play_again():
                break
            self.reset()
        self.show_closing_screen()

    def closing_screen_message(self):
        return f"""
Thank you for playing at Rodes Black Jack, {self.gambler.name}!{self.SPACE}
{self.closing_screen_message_which()}
        """
    
    def closing_screen_message_which(self):
        return [
            "You have broken even. Oh well, maybe next time.n",
            self.closing_screen_message_win(),
            self.closing_screen_message_lose()
        ][self.sign(self.gambler.cash, self.GAMBLER_STAKE)]

    def closing_screen_message_lose(self):
        return f"""
You have lost ${self.GAMBLER_STAKE - self.gambler.cash}.{self.SPACE}

But not to worry. Just spend a year washing dishes in our kitchen and 
we'll call it even.{self.SPACE}

See you tomorrow at 5 a.m. Don't be late!{self.SPACE}
        """

    def closing_screen_message_win(self):
        return f"""
You have won ${self.gambler.cash - self.GAMBLER_STAKE}.

We'll be keeping the money, of course. After all, it was ours to begin with.{self.SPACE}

Stop back and see us again!{self.SPACE}
        """

    def opening_screen_message(self):
        return f"""
Welcome {self.gambler.name}!

You have been awarded a gambling spree at Rodes Black Jack,
our favorite casino!{self.SPACE}Black Jack is the game we play ... sort of. 
No doubling down, and no splitting pairs.{self.SPACE}

You have ${self.GAMBLER_STAKE} to play with. Bet is ${self.BET} per hand.{self.SPACE}Black Jack (natural {App.BUST_VALUE}) 
pays {self.NATURAL_MULTIPLIER} to 1. 

Good luck!{self.SPACE}
        """

    def play_again(self):
        char = input('Please enter Q to quit, or anything else to play again: ')
        print("n")
        return char.lower() != 'q'

    def reset(self):
        self.dealer.hide_hand = True
        if len(self.deck.cards) > self.NEW_DECK_COUNT:
            return
        self.say('Reshuffling ... ', 1)
        self.wait(App.SLEEP_TIME * 2)
        self.deck.new_deck()

    def show_closing_screen(self):
        self.cls()
        print(App.HEADER)
        print(self.closing_screen_message())
        input(f"Please hit "Enter" to leave ... ")
        print("Goodbye!nn")

    def show_opening_screen(self):
        self.cls()
        print(App.HEADER)
        print(self.opening_screen_message())
        input(f"Please hit "Enter" to continue ... ")
        
game = BlackJack()
game.play()

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from itertools import product

import random

import os

import time

class App:

BUST_VALUE = 21

DEALER_STAND_VALUE = 17

SCREEN_WIDTH = 60

HEADER = f"n{'Rodes Black Jack'.center(SCREEN_WIDTH)}n"

SLEEP_TIME = 1 # How long to wait between dealer cards dealt, etc.

class UtilsMixin:

def cls(self):

os.system('clear||cls')

def say(self, message, new_lines=0):

print(message)

print("n" * new_lines)

def wait(self, interval):

time.sleep(interval)

def sign(self, val1, val2):

difference = val1 - val2

if difference > 0:

return 1

elif difference < 0:

return -1

else:

return 0

class Deck:

_CARD_VALUES = {

'2': 2,

'3': 3,

'4': 4,

'5': 5,

'6': 6,

'7': 7,

'8': 8,

'9': 9,

'10': 10,

'J': 10,

'Q': 10,

'K': 10,

'A': 11

}

_RANKS = '2 3 4 5 6 7 8 9 10 J Q K A'.split()

_SUITS = ["u2660", "u2661", "u2662", "u2663"]

def __init__(self):

self.new_deck()

def new_deck(self):

cards = [*product(Deck._RANKS, Deck._SUITS)]

random.shuffle(cards)

self.cards = cards

class Player(UtilsMixin):

def __init__(self, deck):

self.deck = deck

self.hand = None

def new_hand(self):

self.hand = []

for _ in range(2):

self.hit()

self.calc_score()

def calc_score(self):

total = 0

for card in self.hand:

total += Deck._CARD_VALUES[card[0]]

aces = sum(1 for val in self.hand if val[0] == 'A')

while total > App.BUST_VALUE and aces > 0:

total -= 10

aces -= 1

self.score = total

def hit(self):

self.hand.append(self.deck.cards.pop())

class Gambler(Player):

def __init__(self, deck, cash):

super().__init__(deck)

self.cash = cash

self.name = self.choose_name()

def turn(self, table):

while True:

play = self.play_decision()

if play == 'h':

self.hit()

self.calc_score()

table.show()

if self.score > App.BUST_VALUE or play == 's':

break

def choose_name(self):

first_time = True

the_name = ''

self.cls()

welcome = "nWelcome to Rodes Black Jack! "

while True:

the_name = input(f"{welcome + 'W' if first_time else 'So, w'}hat's your name? ")

if the_name.replace(' ', '') == '':

first_time = False

self.say("nSorry, only The Man With No Name is allowed to play without a name.")

else:

break

return the_name

def play_decision(self):

while True:

play = input('Hit or stand (H or S)? ').lower()

if play in 'hs':

return play

else:

self.say("nInvalid value. Please try again.", 1)

class Dealer(Player):

def __init__(self, deck):

super().__init__(deck)

self.hide_hand = True

def turn(self, table):

self.hide_hand = False

self.wait(App.SLEEP_TIME)

while True:

table.show()

self.wait(App.SLEEP_TIME)

if self.score >= App.DEALER_STAND_VALUE:

break

else:

self.hit()

self.calc_score()

class Table(UtilsMixin):

def __init__(self, dealer, gambler):

self.dealer = dealer

self.gambler = gambler

def show(self):

self.cls()

print(f"""

{App.HEADER}

{'Dealer'.center(App.SCREEN_WIDTH)}

{self.create_hand_view(self.dealer).center(App.SCREEN_WIDTH)}

{' '.join(Deck._SUITS).center(App.SCREEN_WIDTH)}

{self.create_hand_view(self.gambler).center(App.SCREEN_WIDTH)}

{self.gambler.name.center(App.SCREEN_WIDTH)}

Player score: {self.gambler.score}

Dealer score: {'??' if self.dealer.hide_hand else self.dealer.score}

Player cash: ${self.gambler.cash}

""")

def create_hand_view(self, player):

if type(player).__name__ == 'Dealer' and player.hide_hand:

return ''.join(player.hand[0])

return ' '.join(''.join(h) for h in player.hand)

class Round(UtilsMixin):

NATURAL_YES = 'Got one!'

NATURAL_NO = 'Not this time.'

def __init__(self, dealer, gambler, table):

self.dealer = dealer

self.gambler = gambler

self.table = table

self.result = None

def play(self):

self.gambler.new_hand()

self.dealer.new_hand()

self.table.show()

self.dealer_check_natural()

self.result = self.calc_natural_result()

if self.result != None:

self.dealer.hide_hand = False

self.table.show()

return

self.table.show()

self.gambler.turn(self.table)

self.result = self.calc_result()

if self.result != None:

return

self.dealer.turn(self.table)

self.result = self.calc_result()

def calc_natural_result(self):

if (self. dealer.score == App.BUST_VALUE

and self.gambler.score == App.BUST_VALUE):

return 'natural_push'

if self. dealer.score == App.BUST_VALUE:

return 'dealer_natural'

if self. gambler.score == App.BUST_VALUE:

return 'gambler_natural'

return None

def calc_result(self):

if self.gambler.score > App.BUST_VALUE:

return 'gambler_bust'

if self.dealer.hide_hand:

return None

if self.dealer.score > App.BUST_VALUE:

return 'dealer_bust'

return ['push', 'gambler', 'dealer'][self.sign(self.gambler.score, self.dealer.score)]

def dealer_check_natural(self):

if Deck._CARD_VALUES[self.dealer.hand[0][0]] < 10:

return

print(f"Dealer is checking for a natural {App.BUST_VALUE} ... ")

self.wait(App.SLEEP_TIME)

print(f"{self.NATURAL_YES if self.dealer.score == App.BUST_VALUE else self.NATURAL_NO}n")

self.wait(App.SLEEP_TIME)

class BlackJack(UtilsMixin):

BET = 1

NATURAL_MULTIPLIER = 10

GAMBLER_STAKE = 50

SPACE = ' '

# Increasing App.BUST_VALUE requires that NEW_DECK_COUNT be increased as

# well. To avoid the possibility of an error from trying to deal from an

# empty deck, NEW_DECK_COUNT has to be at least as high as the maximum

# possible number of cards for both hands.

NEW_DECK_COUNT = 18

APPLY_BET = {

'gambler_natural': BET * NATURAL_MULTIPLIER,

'dealer_bust': BET,

'gambler': BET,

'natural_push': 0,

'push': 0,

'dealer': -BET,

'gambler_bust': -BET,

'dealer_natural': -BET

}

HAND_RESULT_PROMPT = {

'gambler_natural': f"Player holds a natural {App.BUST_VALUE}! Player wins ${APPLY_BET['gambler_natural']}.",

'dealer_bust': 'Dealer busted. Player wins.',

'gambler': 'Player wins.',

'natural_push': f"Dealer and player both hold a natural {App.BUST_VALUE}! That's a push.",

'push': 'Push.',

'dealer': 'Dealer wins.',

'gambler_bust': 'Player busted. Dealer wins.',

'dealer_natural': f"Dealer holds a natural {App.BUST_VALUE}. Dealer wins."

}

def __init__(self):

self.deck = Deck()

self.dealer = Dealer(self.deck)

self.gambler = Gambler(self.deck, self.GAMBLER_STAKE)

self.table = Table(self.dealer, self.gambler)

def play(self):

self.show_opening_screen()

while True:

round = Round(self.dealer, self.gambler, self.table)

round.play()

self.dealer.hide_hand = False

self.gambler.cash += self.APPLY_BET[round.result]

self.table.show()

self.say(self.HAND_RESULT_PROMPT[round.result], 2)

if not self.play_again():

break

self.reset()

self.show_closing_screen()

def closing_screen_message(self):

return f"""

Thank you for playing at Rodes Black Jack, {self.gambler.name}!{self.SPACE}

{self.closing_screen_message_which()}

"""

def closing_screen_message_which(self):

return [

"You have broken even. Oh well, maybe next time.n",

self.closing_screen_message_win(),

self.closing_screen_message_lose()

][self.sign(self.gambler.cash, self.GAMBLER_STAKE)]

def closing_screen_message_lose(self):

return f"""

You have lost ${self.GAMBLER_STAKE - self.gambler.cash}.{self.SPACE}

But not to worry. Just spend a year washing dishes in our kitchen and

we'll call it even.{self.SPACE}

See you tomorrow at 5 a.m. Don't be late!{self.SPACE}

"""

def closing_screen_message_win(self):

return f"""

You have won ${self.gambler.cash - self.GAMBLER_STAKE}.

We'll be keeping the money, of course. After all, it was ours to begin with.{self.SPACE}

Stop back and see us again!{self.SPACE}

"""

def opening_screen_message(self):

return f"""

Welcome {self.gambler.name}!

You have been awarded a gambling spree at Rodes Black Jack,

our favorite casino!{self.SPACE}Black Jack is the game we play ... sort of.

No doubling down, and no splitting pairs.{self.SPACE}

You have ${self.GAMBLER_STAKE} to play with. Bet is ${self.BET} per hand.{self.SPACE}Black Jack (natural {App.BUST_VALUE})

pays {self.NATURAL_MULTIPLIER} to 1.

Good luck!{self.SPACE}

"""

def play_again(self):

char = input('Please enter Q to quit, or anything else to play again: ')

print("n")

return char.lower() != 'q'

def reset(self):

self.dealer.hide_hand = True

if len(self.deck.cards) > self.NEW_DECK_COUNT:

return

self.say('Reshuffling ... ', 1)

self.wait(App.SLEEP_TIME * 2)

self.deck.new_deck()

def show_closing_screen(self):

self.cls()

print(App.HEADER)

print(self.closing_screen_message())

input(f"Please hit "Enter" to leave ... ")

print("Goodbye!nn")

def show_opening_screen(self):

self.cls()

print(App.HEADER)

print(self.opening_screen_message())

input(f"Please hit "Enter" to continue ... ")

game = BlackJack()

game.play()

Collapse

Web Technologies: HTML5, CSS, jQuery, PHP, MySQL

This code sample from the PPLS Tracking System application displays a modal dialog box. It handles the adding of parts to or removing of parts from a particular distributor in a vendor table. The context is editing a specific vendor record. The user may add or remove parts carried by the vendor. If adding, the user gets a list of all parts not currently carried by the vendor, checks the ones to add and saves. If removing, the user gets a list of all parts currently carried by the vendor, checks the ones to remove and saves.

The code also supports toggling of detail data for each record. The user clicks a button to the left of the row, and the detail is presented in a dropdown format underneath the row. Clicking again removes the detail.

Expand

This code sample from the PPLS Tracking System application displays a modal dialog box. It handles the adding of parts to or removing of parts from a particular distributor in a vendor table. The context is editing a specific vendor record. The user may add or remove parts carried by the vendor. If adding, the user gets a list of all parts not currently carried by the vendor, checks the ones to add and saves. If removing, the user gets a list of all parts currently carried by the vendor, checks the ones to remove and saves.

The code also supports toggling of detail data for each record. The user clicks a button to the left of the row, and the detail is presented in a dropdown format underneath the row. Clicking again removes the detail.

This is one of several modal dialogs of this type. Some of the code given here is reused for other editing contexts involving the adding or removing of child records.

The sample contains all the modules required for this particular dialog box, using a range of popular web technologies: JavaScript, jQuery, jQuery-UI, CSS, AJAX, JSON, PHP and MySQL. It also uses the jQuery DataTables plugin.

vdrmodal.php, the modal dialog page


<?php
    session_start();
    require_once('classes/databaseconnector.php');
    require_once('includes/phpConstants.php');
    require_once('includes/phpHelpers.php');
    require_once('includes/phpFormatHelpers.php');

    $theDb = new CDbConnector();
    $theDb->Connect();

    $Id = $_GET['id'];
    $AOrR = $_GET['aorr']; // Add or Remove records; passed in via GET variables
    
    $rs = GetChildren('getPartDists' , $Id, $AOrR);
?>
<!DOCTYPE html>
<html>
<head>
     <script type="text/javascript" language="JavaScript"> 

        ///This function creates the HTML for a detail table and returns it as a string.

        function format(d) {
            var x = 
                '<table cellpadding="5" cellspacing="0" border="0" style="padding-left:50px;">'+
                    '<tr>'+
                        '<td>CAGE:</td>'+
                        '<td>'+d.oCAGE+'</td>'+
                    '</tr>'+
                    '<tr>'+
                        '<td>Status:</td>'+
                        '<td>'+d.oStatus+'</td>'+
                    '</tr>'+
                    '<tr>'+
                        '<td>UOM:</td>'+
                        '<td>'+d.UOM+'</td>'+
                    '</tr>'+
                    '<tr>'+
                        '<td>QUP:</td>'+
                        '<td>'+d.QUP+'</td>'+
                    '</tr>'+
                '</table>';
            return x;
        }

        $(document).ready( function() {
            var theData = { "data": <?php echo $rs; ?> } 
            for(var i=0;i<theData.data.length;i++)
            {
                theData.data[i].checkBox = '<input type="checkbox">';
            }
            var table = $('#vdrDetail').DataTable(
            {
                'data': theData.data,
                'columns': [
                    {
                        'className': 'details-control', // The details-control class has the background value set to a button image
                        'orderable': false,
                        'data': null,
                        'defaultContent': '',
                        'width': '10px'
                    },
                    { 'data': 'PartNo' },
                    { 'data': 'pStatus' },
                    { 'data': 'NSN' },
                    { 'data': 'Desc' },
                    { 'data': 'oName' },
                    {
                        'className': 'row-select',
                        'orderable': false,
                        'data': 'checkBox',
                        'width': '7px',
                    }
                ],
                'order': [[1, 'asc']],
                paginate: false,
                scrollY: '352px', 
                scrollCollapse: true,
                'infoCallback': function( settings, start, end, max, total, pre ) {
                    if (0 == max) { return 'Showing 0 records'; }
                    if (1 == max) { return 'Showing 1 record'; }
                    if (total == max) { return 'Showing ' + max + ' records'; }
                    return 'Showing ' + total + ' of ' + max + ' records';
                },
            });
             
            /// Sets up the button click event for child rows. It's important to use on() here instead of click(), since the button is set
            /// up dynamically while rendering the data table. click() will register the event only for instances of the class that exist on
            /// page load, so if you re-render the table, the event won't be registered for new instances of the class. on() delegates the
            /// event to the class itself rather than registering existing instances of it as listeners. That way, any class members get
            /// registered whenever they are instantiated during the lifetime of the page.

            $('#vdrDetail tbody').on('click', 'td.details-control', function () {
                var tr = $(this).closest('tr');
                var row = table.row( tr );
                if ( row.child.isShown() ) {
                    row.child.hide();
                    tr.removeClass('shown'); // shows a green button with a plus on it for "open"
                }
                else {
                    row.child( format(row.data()) ).show();
                    tr.addClass('shown'); // shows a red button with a minus on it for "close"
                }
            }).on('click', 'td.row-select input', function(e) {
                e.stopPropagation(); // Clicking on the check box automatically toggles the check; the click event then propagates to the 
                                     // container, whose click event toggles the check back again--unless we stop it here.
                $('#btnSave').button('option', 'disabled', 0 == $('#vdrDetail input:checked').length); // Disables the save button if no 
                                                                                                       // checkboxes are checked 
            }).on('click', 'td.row-select', function() { // So the user can click anywhere in the cell rather than just the checkbox
                this.firstChild.checked = !this.firstChild.checked;
                $('#btnSave').button('option', 'disabled', 0 == $('#vdrDetail input:checked').length); 
            });
            return table;           
        });
    </script>
</head>
<body>
    <table id="vdrDetail" class="display" cellspacing="0" width="100%">
        <thead>
            <tr>
                <th></th>
                <th>Part No</th>
                <th>Status</th>
                <th>NSN</th>
                <th>Desc</th>
                <th>OEM</th>
                <th></th>
            </tr>
        </thead>
    </table>
<?php
    $theDb->Disconnect();
    unset ($theDb);
?>
</body>
</html>

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<?php

session_start();

require_once('classes/databaseconnector.php');

require_once('includes/phpConstants.php');

require_once('includes/phpHelpers.php');

require_once('includes/phpFormatHelpers.php');

$theDb = new CDbConnector();

$theDb->Connect();

$Id = $_GET['id'];

$AOrR = $_GET['aorr']; // Add or Remove records; passed in via GET variables

$rs = GetChildren('getPartDists' , $Id, $AOrR);

<!DOCTYPE html>

<html>

<head>

///This function creates the HTML for a detail table and returns it as a string.

function format(d) {

var x =

'<table cellpadding="5" cellspacing="0" border="0" style="padding-left:50px;">'+

'<tr>'+

'<td>CAGE:</td>'+

'<td>'+d.oCAGE+'</td>'+

'</tr>'+

'<tr>'+

'<td>Status:</td>'+

'<td>'+d.oStatus+'</td>'+

'</tr>'+

'<tr>'+

'<td>UOM:</td>'+

'<td>'+d.UOM+'</td>'+

'</tr>'+

'<tr>'+

'<td>QUP:</td>'+

'<td>'+d.QUP+'</td>'+

'</tr>'+

'</table>';

return x;

}

$(document).ready( function() {

var theData = { "data": <?php echo $rs; ?> }

for(var i=0;i<theData.data.length;i++)

{

theData.data[i].checkBox = '<input type="checkbox">';

}

var table = $('#vdrDetail').DataTable(

{

'data': theData.data,

'columns': [

{

'className': 'details-control', // The details-control class has the background value set to a button image

'orderable': false,

'data': null,

'defaultContent': '',

'width': '10px'

{ 'data': 'PartNo' },

{ 'data': 'pStatus' },

{ 'data': 'NSN' },

{ 'data': 'Desc' },

{ 'data': 'oName' },

{

'className': 'row-select',

'orderable': false,

'data': 'checkBox',

'width': '7px',

}

'order': [[1, 'asc']],

paginate: false,

scrollY: '352px',

scrollCollapse: true,

'infoCallback': function( settings, start, end, max, total, pre ) {

if (0 == max) { return 'Showing 0 records'; }

if (1 == max) { return 'Showing 1 record'; }

if (total == max) { return 'Showing ' + max + ' records'; }

return 'Showing ' + total + ' of ' + max + ' records';

});

/// Sets up the button click event for child rows. It's important to use on() here instead of click(), since the button is set

/// up dynamically while rendering the data table. click() will register the event only for instances of the class that exist on

/// page load, so if you re-render the table, the event won't be registered for new instances of the class. on() delegates the

/// event to the class itself rather than registering existing instances of it as listeners. That way, any class members get

/// registered whenever they are instantiated during the lifetime of the page.

$('#vdrDetail tbody').on('click', 'td.details-control', function () {

var tr = $(this).closest('tr');

var row = table.row( tr );

if ( row.child.isShown() ) {

row.child.hide();

tr.removeClass('shown'); // shows a green button with a plus on it for "open"

}

else {

row.child( format(row.data()) ).show();

tr.addClass('shown'); // shows a red button with a minus on it for "close"

}

}).on('click', 'td.row-select input', function(e) {

e.stopPropagation(); // Clicking on the check box automatically toggles the check; the click event then propagates to the

// container, whose click event toggles the check back again--unless we stop it here.

$('#btnSave').button('option', 'disabled', 0 == $('#vdrDetail input:checked').length); // Disables the save button if no

// checkboxes are checked

}).on('click', 'td.row-select', function() { // So the user can click anywhere in the cell rather than just the checkbox

this.firstChild.checked = !this.firstChild.checked;

$('#btnSave').button('option', 'disabled', 0 == $('#vdrDetail input:checked').length);

});

return table;

});

</script>

</head>

<body>

<thead>

<tr>

<th>Status</th>

</tr>

</thead>

</table>

<?php

$theDb->Disconnect();

unset ($theDb);

</body>

</html>

`dialog()` function code, from viewvendor.php


$('#btnPartAdd, #btnPartRem').on('click', function(e, ui) {
    var aOrR = ('btnPartAdd' == this.id ? 1 : 0); // If the user hit Add, we're adding, if he hit Removed, we're removing
    $('#dialogChildren').load('vdrmodal.php?id=' + id + '&aorr=' + aOrR, function(table) {
        $('#dialogChildren').dialog( {
            modal: true,
            maxHeight: 580,
            width: 1100,
            position: {my:'top', at:'top+60'},
            buttons: [
                {
                    id: 'btnSave', 
                    text: 'Save',
                    click: function(e, ui) {
                        var theData = $('#vdrDetail').DataTable().rows().data();
                        var theNodes = $('#vdrDetail').DataTable().rows().nodes();
                        var paramString = '';
                        for(var i=0;i<theData.length;i++) { // find every checked row and add or remove its data from the appropriate
                                                            // underlying table
                            if (theNodes[i].cells[6].children[0].checked) {
                                paramString = 'table=partsdists&field1=PartId&field2=DistId&aorr=' + aOrR + '&id1=' + theData[i].Id +
                                    '&id2=' + id;
                                $.ajax( {
                                    url: 'cdchildren.php', // handles the adding or removing of child records
                                    data: paramString
                                });                                
                            }
                        }
                        $('#hdnId').val(id);
                        $('#hdnAccordionActive').val(2);
                        $('#frmPostVars').submit();
                        $(this).dialog('close');
                    },
                    disabled: true
                },
                {
                    text: 'Cancel',
                    click: function() {
                        $(this).dialog('close');
                    }
                }
            ],
            title: (1 == aOrR ? 'Adding' : 'Removing') + ' Parts',
            open: function(e, ui) {
                $('#vdrDetail').DataTable().columns.adjust();
                $('.ui-dialog-buttonset button:first-of-type .ui-button-text')
                .text((1 == aOrR ? 'Add' : 'Remove') + ' Selected');
            }
        });
    });
});

$('#btnPartAdd, #btnPartRem').on('click', function(e, ui) {

var aOrR = ('btnPartAdd' == this.id ? 1 : 0); // If the user hit Add, we're adding, if he hit Removed, we're removing

$('#dialogChildren').load('vdrmodal.php?id=' + id + '&aorr=' + aOrR, function(table) {

$('#dialogChildren').dialog( {

modal: true,

maxHeight: 580,

width: 1100,

position: {my:'top', at:'top+60'},

buttons: [

{

id: 'btnSave',

text: 'Save',

click: function(e, ui) {

var theData = $('#vdrDetail').DataTable().rows().data();

var theNodes = $('#vdrDetail').DataTable().rows().nodes();

var paramString = '';

for(var i=0;i<theData.length;i++) { // find every checked row and add or remove its data from the appropriate

// underlying table

if (theNodes[i].cells[6].children[0].checked) {

paramString = 'table=partsdists&field1=PartId&field2=DistId&aorr=' + aOrR + '&id1=' + theData[i].Id +

'&id2=' + id;

$.ajax( {

url: 'cdchildren.php', // handles the adding or removing of child records

data: paramString

});

}

$('#hdnId').val(id);

$('#hdnAccordionActive').val(2);

$('#frmPostVars').submit();

$(this).dialog('close');

disabled: true

{

text: 'Cancel',

click: function() {

$(this).dialog('close');

}

title: (1 == aOrR ? 'Adding' : 'Removing') + ' Parts',

open: function(e, ui) {

$('#vdrDetail').DataTable().columns.adjust();

$('.ui-dialog-buttonset button:first-of-type .ui-button-text')

.text((1 == aOrR ? 'Add' : 'Remove') + ' Selected');

}

});

cdchildren.php: adds and removes child records


        <?php
            session_start();
            require_once('classes/databaseconnector.php');
            require_once('includes/phpHelpers.php');
        
            $theDb = new CDbConnector();
            $theDb->Connect();
        
            $Table = $_GET['table'];
            $AOrR = $_GET['aorr'];
            $Id1 = $_GET['id1'];
            $Id2 = $_GET['id2'];
            $Field1 = $_GET['field1'];
            $Field2 = $_GET['field2'];
            
            if (0 == $AOrR)
            {
                RemChild($Table, $Field1, $Field2, $Id1, $Id2);
            }
            else
            {
                AddChild($Table, $Field1, $Field2, $Id1, $Id2);    
            }
            
            $theDb->Disconnect();
            unset ($theDb);
        ?>

<?php

session_start();

require_once('classes/databaseconnector.php');

require_once('includes/phpHelpers.php');

$theDb = new CDbConnector();

$theDb->Connect();

$Table = $_GET['table'];

$AOrR = $_GET['aorr'];

$Id1 = $_GET['id1'];

$Id2 = $_GET['id2'];

$Field1 = $_GET['field1'];

$Field2 = $_GET['field2'];

if (0 == $AOrR)

{

RemChild($Table, $Field1, $Field2, $Id1, $Id2);

}

else

{

AddChild($Table, $Field1, $Field2, $Id1, $Id2);

}

$theDb->Disconnect();

unset ($theDb);

AddChild, RemChild, GetChildren and rsToJSON, from phpHelpers.php


/// AddChild and RemChild are used to add and remove records from an associative entity table which maintains a many-to-many relationship
/// between two kernel entity tables. The structure of the table is always two fields, which are a composite primary key. The record
/// contents are always one foreign key from each of the kernel entity tables. $Table is the associative entity table name, $Field1 and
/// $Field2 are the names of the fields making up the composite primary key in the table, and $Id1 and $Id2 are the values for the
/// record to be created or deleted.

function AddChild($Table, $Field1, $Field2, $Id1, $Id2, $theDb)
{
    $query =
        "INSERT INTO $Table ($Field1, $Field2)
            VALUES ('$Id1', '$Id2')";
    $rs = mysqli_query($theDb->connection, $query) or die(mysqli_error($theDb->connection));
}

function RemChild($Table, $Field1, $Field2, $Id1, $Id2, $theDb)
{
    $query =
        "DELETE FROM $Table 
            WHERE $Field1 = '$Id1'
            AND $Field2 = '$Id2'";
    $rs = mysqli_query($theDb->connection, $query) or die(mysqli_error($theDb->connection));
}

/// GetChildren is used to call several different stored procedures. Each of them pulls all the child records from a specific child table
/// for a specific record in a parent table, or if $Param2 is set, pulls all the child records from said child table that are NOT associated
/// with said parent record. $Param2 is set when in the Add context, and is not set when in the Remove context. The results are returned as
/// JSON data to the calling web page, to be displayed by the DataTable functions.

function GetChildren($ProcName, $Param1, $Param2, $theDb)
{
    $query = "CALL " . $ProcName . "(" . $Param1 . (isset($Param2) ? ", " . $Param2 : "") . ")";
    $rs = mysqli_query($theDb->connection, $query) or die(mysqli_error($theDb->connection));
    
    return rsToJSON($rs);
}

/// rsToJSON casts a php resultset to JSON for consumption by AJAX calls.
function rsToJSON($rs)
{
    return json_encode(rsToArray($rs));
}

/// AddChild and RemChild are used to add and remove records from an associative entity table which maintains a many-to-many relationship

/// between two kernel entity tables. The structure of the table is always two fields, which are a composite primary key. The record

/// contents are always one foreign key from each of the kernel entity tables. $Table is the associative entity table name, $Field1 and

/// $Field2 are the names of the fields making up the composite primary key in the table, and $Id1 and $Id2 are the values for the

/// record to be created or deleted.

function AddChild($Table, $Field1, $Field2, $Id1, $Id2, $theDb)

{

$query =

"INSERT INTO $Table ($Field1, $Field2)

VALUES ('$Id1', '$Id2')";

$rs = mysqli_query($theDb->connection, $query) or die(mysqli_error($theDb->connection));

}

function RemChild($Table, $Field1, $Field2, $Id1, $Id2, $theDb)

{

$query =

"DELETE FROM $Table

WHERE $Field1 = '$Id1'

AND $Field2 = '$Id2'";

$rs = mysqli_query($theDb->connection, $query) or die(mysqli_error($theDb->connection));

}

/// GetChildren is used to call several different stored procedures. Each of them pulls all the child records from a specific child table

/// for a specific record in a parent table, or if $Param2 is set, pulls all the child records from said child table that are NOT associated

/// with said parent record. $Param2 is set when in the Add context, and is not set when in the Remove context. The results are returned as

/// JSON data to the calling web page, to be displayed by the DataTable functions.

function GetChildren($ProcName, $Param1, $Param2, $theDb)

{

$query = "CALL " . $ProcName . "(" . $Param1 . (isset($Param2) ? ", " . $Param2 : "") . ")";

$rs = mysqli_query($theDb->connection, $query) or die(mysqli_error($theDb->connection));

return rsToJSON($rs);

}

/// rsToJSON casts a php resultset to JSON for consumption by AJAX calls.

function rsToJSON($rs)

{

return json_encode(rsToArray($rs));

}

cdbconnector.php: defines the CDbConnector class, used to connect to the MySQL database


        <?php
        class CDbConnector
        {
            var $hostname;          // The database server to which we are connecting
            var $usernamedb;        // The user name that we use to connect to the DB
            var $passworddb;        // The password that we use to connect to the DB
            var $dbName;            // The name of the database.
            var $connection;        // Connection to DB server
            var $dbSelect;          // Reference to the database that we will use
            var $bConnected;
        
            // Constructor
            function __construct()
            {
                $this->bConnected = false;
            }
        
            function Connect()
            {
                $this->hostname     = '************';
                $this->usernamedb   = '************';
                $this->passworddb   = '************';
                $this->dbName       = "************";
        
                $this->connection = mysqli_connect(
                                                            $this->hostname,
                                                            $this->usernamedb,
                                                            $this->passworddb) or die('Cannot establish connection');
        
                $this->dbSelect = mysqli_select_db($this->connection, $this->dbName) or die('Cannot select DB');
                $this->bConnected = true;
        }
        
            function Disconnect()
            {
                if (true == $this->bConnected)
                    mysqli_close($this->connection);
            }
        }
        ?>

<?php

class CDbConnector

{

var $hostname; // The database server to which we are connecting

var $usernamedb; // The user name that we use to connect to the DB

var $passworddb; // The password that we use to connect to the DB

var $dbName; // The name of the database.

var $connection; // Connection to DB server

var $dbSelect; // Reference to the database that we will use

var $bConnected;

// Constructor

function __construct()

{

$this->bConnected = false;

}

function Connect()

{

$this->hostname = '************';

$this->usernamedb = '************';

$this->passworddb = '************';

$this->dbName = "************";

$this->connection = mysqli_connect(

$this->hostname,

$this->usernamedb,

$this->passworddb) or die('Cannot establish connection');

$this->dbSelect = mysqli_select_db($this->connection, $this->dbName) or die('Cannot select DB');

$this->bConnected = true;

}

function Disconnect()

{

if (true == $this->bConnected)

mysqli_close($this->connection);

}

getPartDists: MySQL proc to get parts for one distributor


        CREATE PROCEDURE getPartDists (theID int, adding bit)
        BEGIN
        IF adding = 1 then -- Get all the parts that aren't associated with the vendor
            select 
            p.id as Id,
            n.nsn as NSN,
            n.ShortDesc as 'Desc',
            p.partno as PartNo,
            p.memo as Memo,
            v.CAGE as oCAGE,
            vs.Code as oStatus,
            v.Name as oName,
            ps.Code as pStatus,
            u.Code as UOM,
            q.Description as QUP
            from parts p
            join nsns n on p.nsnid = n.id
            left join vendors v on p.vendorid = v.id
            left join vendorstatus vs on v.statusid = vs.id
            join uoms u on p.uomid = u.id
            join qups q on p.qupid = q.id
            join partstatus ps on p.statusid = ps.id
            where not exists (select partid from partsdists where partid = p.id and distid = theID);
        ELSE -- Get all the parts that are
            select 
            p.id as Id,
            n.nsn as NSN,
            n.ShortDesc as 'Desc',
            p.partno as PartNo,
            p.memo as Memo,
            v.CAGE as oCAGE,
            vs.Code as oStatus,
            v.Name as oName,
            ps.Code as pStatus,
            u.Code as UOM,
            q.Description as QUP
            from parts p
            join nsns n on p.nsnid = n.id
            left join vendors v on p.vendorid = v.id
            left join vendorstatus vs on v.statusid = vs.id
            join uoms u on p.uomid = u.id
            join qups q on p.qupid = q.id
            join partstatus ps on p.statusid = ps.id
            where exists (select partid from partsdists where partid = p.id and distid = theID);
        END IF;
        END$$

CREATE PROCEDURE getPartDists (theID int, adding bit)

BEGIN

IF adding = 1 then -- Get all the parts that aren't associated with the vendor

select

p.id as Id,

n.nsn as NSN,

n.ShortDesc as 'Desc',

p.partno as PartNo,

p.memo as Memo,

v.CAGE as oCAGE,

vs.Code as oStatus,

v.Name as oName,

ps.Code as pStatus,

u.Code as UOM,

q.Description as QUP

from parts p

join nsns n on p.nsnid = n.id

left join vendors v on p.vendorid = v.id

left join vendorstatus vs on v.statusid = vs.id

join uoms u on p.uomid = u.id

join qups q on p.qupid = q.id

join partstatus ps on p.statusid = ps.id

where not exists (select partid from partsdists where partid = p.id and distid = theID);

ELSE -- Get all the parts that are

select

p.id as Id,

n.nsn as NSN,

n.ShortDesc as 'Desc',

p.partno as PartNo,

p.memo as Memo,

v.CAGE as oCAGE,

vs.Code as oStatus,

v.Name as oName,

ps.Code as pStatus,

u.Code as UOM,

q.Description as QUP

from parts p

join nsns n on p.nsnid = n.id

left join vendors v on p.vendorid = v.id

left join vendorstatus vs on v.statusid = vs.id

join uoms u on p.uomid = u.id

join qups q on p.qupid = q.id

join partstatus ps on p.statusid = ps.id

where exists (select partid from partsdists where partid = p.id and distid = theID);

END IF;

END$$

Collapse

C#: Multithreading, Reflection and Dynamic Binding, Using a RESTful Service

This sample code demonstrates use of various features and techniques in C#. The code implements these technical requirements:

Access data exposed as a web service, and export it to a local file.

Both XML and JSON formats need to be supported by requirement 1.

The export functionality must be a singleton instance, and must support multithreading.

The thread, data access, and export functionality should be addressed as separate concerns.

Provide a custom event that is raised when the export is finished, with two arguments: one to keep track of whether the export succeeded and one to provide a target file name for the exported data.

Define all of the export class’s functionality in abstract terms, and have the class implement the abstractions.

Expand

This sample code demonstrates use of various features and techniques in C#. The code implements these technical requirements:

Access data exposed as a web service, and export it to a local file.

Both XML and JSON formats need to be supported by requirement 1.

The export functionality must be a singleton instance, and must support multithreading.

The thread, data access, and export functionality should be loosely coupled.

Provide a custom event that is raised when the export is finished, with two arguments: one to keep track of whether the export succeeded and one to provide a target file name for the exported data.

Define all of the export class’s functionality in abstract terms, and have the class implement the abstractions.

To accomplish this, we have three separate classes, one to retrieve data, one to export it, and a multithreaded client:

The NorthwindDataRetrieve class uses Microsoft’s (abbreviated) Northwind database, which they expose as an OData service on Azure. The method has an overloaded GetData method that returns various generic List objects containing data.

The DataExport class exposes a thread-safe singleton instance of itself, with a generic Export method that can accept any of the List objects returned by the NorthwindDataRetrieve.GetData method. This method also accepts an argument for whether the exported data are to be in XML or in JSON format. It also raises a custom event when finished.

This event can’t quite be defined in fully abstract terms (i. e. in terms of interfaces), per requirement 6. Custom arguments for an event have to inherit the existing EventArgs class, and EventArgs doesn’t expose a public interface (e.g. “iEventArgs”). Therefore, it isn’t possible to define a class deriving from it as an interface (interfaces can’t inherit concrete classes; they have to inherit interfaces). The closest we can come to a fully abstract definition is to define an abstract class that inherits EventArgs and defines the custom event arguments as abstract, while defining everything else in terms of interfaces and delegates.

(Microsoft’s position on why they don’t allow custom implementations of the EventArgs class itself seems reasonable: first, the process of passing arguments to event procedures is a specialization of the process of passing arguments to procedures in general, and procedure logic is already tightly coupled with the logic of passing arguments to them. Therefore, developers using the CLR are unlikely to derive significant advantage from being allowed to create custom implementations of the EventArgs class. Second, if Microsoft decide to change the implementation of EventArgs, they would run the risk of breaking custom implementations of the class if custom implementations were allowed. They don’t feel that the limited additional functionality justifies this risk.)

The Program class is the client. The Main method instantiates some threads that call the DoWork method, passing arguments in a class called ThreadParams. This class has a target file name, a file type (JSON or XML), and an instance of a List object that will hold the retrieved data. DoWork calls GetData, passes the resulting List to the Export method, and calls the event handler once Export raises the ExportFinished event.

Program.cs


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Reflection;
using DataExport;
using NorthwindDataRetrieve;
using System.IO;

namespace ConsoleClient   // The client for the DataExporter class.
{
    public enum FileType
    {
        JSON,
        XML
    }

    /// <summary>
    /// This class represents the parameters passed to each thread in an object.
    /// </summary>
    class ThreadParams 
    {
        private string _filePath;
        private FileType _fileType;
        private IEnumerable<object> _listType;

        public ThreadParams(string filePath, FileType fileType, IEnumerable<object> listType)
        {
            _filePath = filePath;
            _fileType = fileType;
            _listType = listType;
        }

        public string filePath
        { get { return _filePath; } }

        public FileType fileType
        { get { return _fileType; } }

        public IEnumerable<object> listType
        { get { return _listType; } }
    }

    class Program
    {
        /// <summary>
        /// This method sets up three threads, which will each use the same DataExporter object. The threads' Join method joins them to the 
        /// current thread, the one upon which this method (Main) is executing. If we didn't do this, they would execute asynchronously  
        /// relative to this thread, the result of which would be that the WriteLine and ReadKey methods would execute before all the
        /// threads are done with their work. This of course would put all the messages out of order.
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args)
        {
            var p = new ThreadParams[] // An array of parameters corresponding to the array of threads
            {
                new ThreadParams(@"c:cs_sampledataCategoriesJSON.txt", FileType.JSON , new List<Categories>()),
                new ThreadParams(@"c:cs_sampledataProdSuppliersXML.txt", FileType.XML, new List<ProductReorders>()),
                new ThreadParams(@"c:cs_sampledataSupplierProdsXML.txt", FileType.XML, new List<SupplierProducts>())
            };

            var t = new Thread[3];

            for (int i=0; i<3; i++)
            {
                t[i] = new Thread(new ParameterizedThreadStart(doWork));
                t[i].Name = "Thread " + i.ToString();
                t[i].Start(p[i]);
                t[i].Join();
            };

            Console.WriteLine("strike a key when ready...");  // The threads all write messages prior to this line being executed
            Console.ReadKey(true);
        }

        /// <summary>
        /// This method does the work for each thread calling it, calling NorthwindDataRetriever.GetData to get a series of records, and 
        /// using the Singleton DataExporter object to write them to a file. See notes to the Instance method in the DataExport class for
        /// thread safety considerations.
        /// </summary>
        /// <param name="tPar"></param>
        static void doWork(object prms)
        {
            try
            {
                if (!(prms is ThreadParams))
                {
                    throw new ArgumentException(Thread.CurrentThread.Name + ": Argument passed on thread start is not of type ThreadParams; 
                        thread aborted");
                }

                var p = (ThreadParams) prms; // So we don't have to recast prms every time we want to use it
                DataExporter de = DataExporter.Instance; // Simplest way to implement a singleton
                var cRet = new NorthwindDataRetriever();

                // This combination of methods uses reflection to dynamically invoke the NorthwindDataRetreiver.GetData method, with these 
                // steps:
                // 1. Use GetType to get the method list for the NorthwindDataRetriever object.
                // 2. Use GetMethod to get the method signature for GetData. GetMethod (the version we're using here; there are several
                //    overloads) takes two arguments: the name of the method as a string, and an array of Type objects containing the 
                //    method's parameters.
                // 3. Populate the Type array with the desired parameter values. In this case, GetData has only one parameter: cList.
                // 4. There are three possible types that will fit the cList parameter (GetData is overloaded). We need to find out which
                //    type was passed into doWork via the ThreadParams object. Use GetType again to do this.
                // 5. Since cList is an out parameter, use MakeByRefType to declare it as such.
                
                MethodBase cMethod = cRet.GetType().GetMethod("GetData", new Type[] { p.listType.GetType().MakeByRefType() } );

                // The MethodBase object's Invoke method takes two arguments: a reference to the object whose method is being invoked, and
                // an array of System.Object objects. Invoke uses the latter to pass the parameters from the list of Type objects set up by
                // the GetMethod method. Any out parameters in the invoked method are therefore returned as members of this array, and are
                // therefore cast to System.Object. We therefore need to recast this System.Object back to the type of the Type object that
                // we passed to the GetMethod method in the line above.
                //
                // The problem is that we can't do that explicitly in code because we don't know exactly which type we're working with until
                // runtime, and the compiler won't allow an implicit cast from System.Object to any other type. (The compiler won't allow
                // an implicit narrowing conversion, i.e. a conversion from a wider to a narrower type such as from Int64 to Int32. While it
                // might seem less than obvious that System.Object is "wider" than any of the object types that derive from it, the salient
                // consideration is that instances of derived classes qualify as instances of their base class, while the reverse is not
                // so.) To get around this, we need to set the cArgs variable to dynamic. This bypasses the compiler's static type checking,
                // and allows cArgs, when the Export method gets called, to be implicitly cast as whichever List type got passed in here
                // from the ThreadParam object.

                dynamic cArgs = new object[1];
                cMethod.Invoke(cRet, cArgs);
                
                de.OnExportFinished += new DataExporterEvent(de_OnExportFinished); // Subscribes to the OnExportFinished event
                de.Export(cArgs[0], p.filePath, p.fileType);
                de.OnExportFinished -= new DataExporterEvent(de_OnExportFinished); // Unsubscribes from same
            }
            catch (NullReferenceException ex)
            {
                Console.WriteLine("Null Reference Exception in " + Thread.CurrentThread.Name + ": " + ex.Message +
                    " (probable cause is incorrect object type in listType thread parameter)");
                return;
            }
            catch (ArgumentException ex)
            {
                Console.WriteLine(ex.Message);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Unhandled Exception: " + ex.Message);
            }
        }

        /// <summary>
        /// Event handler for DataExport.OnExportFinished event.
        /// </summary>
        static void de_OnExportFinished(iDataExporter sender, aDEEventArgs deargs)
        {
            switch (deargs.ExportStatus)
            {
                case 0:
                    Console.WriteLine("Export routine for " + Thread.CurrentThread.Name + " failed with this error: "
                        + deargs.ReturnMessage);
                    break;
                default:
                    Console.WriteLine("Export to " + deargs.FileName + " successful using " + Thread.CurrentThread.Name);
                    break;
            }
        }
    }
}

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using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading;

using System.Reflection;

using DataExport;

using NorthwindDataRetrieve;

using System.IO;

namespace ConsoleClient // The client for the DataExporter class.

{

public enum FileType

{

JSON,

XML

}

/// <summary>

/// This class represents the parameters passed to each thread in an object.

/// </summary>

class ThreadParams

{

private string _filePath;

private FileType _fileType;

private IEnumerable<object> _listType;

public ThreadParams(string filePath, FileType fileType, IEnumerable<object> listType)

{

_filePath = filePath;

_fileType = fileType;

_listType = listType;

}

public string filePath

{ get { return _filePath; } }

public FileType fileType

{ get { return _fileType; } }

public IEnumerable<object> listType

{ get { return _listType; } }

}

class Program

{

/// <summary>

/// This method sets up three threads, which will each use the same DataExporter object. The threads' Join method joins them to the

/// current thread, the one upon which this method (Main) is executing. If we didn't do this, they would execute asynchronously

/// relative to this thread, the result of which would be that the WriteLine and ReadKey methods would execute before all the

/// threads are done with their work. This of course would put all the messages out of order.

/// </summary>

/// <param name="args"></param>

static void Main(string[] args)

{

var p = new ThreadParams[] // An array of parameters corresponding to the array of threads

{

new ThreadParams(@"c:cs_sampledataCategoriesJSON.txt", FileType.JSON , new List<Categories>()),

new ThreadParams(@"c:cs_sampledataProdSuppliersXML.txt", FileType.XML, new List<ProductReorders>()),

new ThreadParams(@"c:cs_sampledataSupplierProdsXML.txt", FileType.XML, new List<SupplierProducts>())

};

var t = new Thread[3];

for (int i=0; i<3; i++)

{

t[i] = new Thread(new ParameterizedThreadStart(doWork));

t[i].Name = "Thread " + i.ToString();

t[i].Start(p[i]);

t[i].Join();

};

Console.WriteLine("strike a key when ready..."); // The threads all write messages prior to this line being executed

Console.ReadKey(true);

}

/// <summary>

/// This method does the work for each thread calling it, calling NorthwindDataRetriever.GetData to get a series of records, and

/// using the Singleton DataExporter object to write them to a file. See notes to the Instance method in the DataExport class for

/// thread safety considerations.

/// </summary>

/// <param name="tPar"></param>

static void doWork(object prms)

{

try

{

if (!(prms is ThreadParams))

{

throw new ArgumentException(Thread.CurrentThread.Name + ": Argument passed on thread start is not of type ThreadParams;

thread aborted");

}

var p = (ThreadParams) prms; // So we don't have to recast prms every time we want to use it

DataExporter de = DataExporter.Instance; // Simplest way to implement a singleton

var cRet = new NorthwindDataRetriever();

// This combination of methods uses reflection to dynamically invoke the NorthwindDataRetreiver.GetData method, with these

// steps:

// 1. Use GetType to get the method list for the NorthwindDataRetriever object.

// 2. Use GetMethod to get the method signature for GetData. GetMethod (the version we're using here; there are several

// overloads) takes two arguments: the name of the method as a string, and an array of Type objects containing the

// method's parameters.

// 3. Populate the Type array with the desired parameter values. In this case, GetData has only one parameter: cList.

// 4. There are three possible types that will fit the cList parameter (GetData is overloaded). We need to find out which

// type was passed into doWork via the ThreadParams object. Use GetType again to do this.

// 5. Since cList is an out parameter, use MakeByRefType to declare it as such.

MethodBase cMethod = cRet.GetType().GetMethod("GetData", new Type[] { p.listType.GetType().MakeByRefType() } );

// The MethodBase object's Invoke method takes two arguments: a reference to the object whose method is being invoked, and

// an array of System.Object objects. Invoke uses the latter to pass the parameters from the list of Type objects set up by

// the GetMethod method. Any out parameters in the invoked method are therefore returned as members of this array, and are

// therefore cast to System.Object. We therefore need to recast this System.Object back to the type of the Type object that

// we passed to the GetMethod method in the line above.

// The problem is that we can't do that explicitly in code because we don't know exactly which type we're working with until

// runtime, and the compiler won't allow an implicit cast from System.Object to any other type. (The compiler won't allow

// an implicit narrowing conversion, i.e. a conversion from a wider to a narrower type such as from Int64 to Int32. While it

// might seem less than obvious that System.Object is "wider" than any of the object types that derive from it, the salient

// consideration is that instances of derived classes qualify as instances of their base class, while the reverse is not

// so.) To get around this, we need to set the cArgs variable to dynamic. This bypasses the compiler's static type checking,

// and allows cArgs, when the Export method gets called, to be implicitly cast as whichever List type got passed in here

// from the ThreadParam object.

dynamic cArgs = new object[1];

cMethod.Invoke(cRet, cArgs);

de.OnExportFinished += new DataExporterEvent(de_OnExportFinished); // Subscribes to the OnExportFinished event

de.Export(cArgs[0], p.filePath, p.fileType);

de.OnExportFinished -= new DataExporterEvent(de_OnExportFinished); // Unsubscribes from same

}

catch (NullReferenceException ex)

{

Console.WriteLine("Null Reference Exception in " + Thread.CurrentThread.Name + ": " + ex.Message +

" (probable cause is incorrect object type in listType thread parameter)");

return;

}

catch (ArgumentException ex)

{

Console.WriteLine(ex.Message);

}

catch (Exception ex)

{

Console.WriteLine("Unhandled Exception: " + ex.Message);

}

/// <summary>

/// Event handler for DataExport.OnExportFinished event.

/// </summary>

static void de_OnExportFinished(iDataExporter sender, aDEEventArgs deargs)

{

switch (deargs.ExportStatus)

{

case 0:

Console.WriteLine("Export routine for " + Thread.CurrentThread.Name + " failed with this error: "

+ deargs.ReturnMessage);

break;

default:

Console.WriteLine("Export to " + deargs.FileName + " successful using " + Thread.CurrentThread.Name);

break;

}

NorthWindDataRetrieve.cs


using System;
using System.Collections.Generic;
using System.Linq;
// (To use the OData Northwind service, a service reference to "http://services.odata.org/Northwind/Northwind.svc/" must be included in
// the project.)
using NorthwindDataExporter.ODataNorthwindService;

namespace NorthwindDataRetrieve
{
    /// <summary>
    /// This is one of the classes that can be plugged into the List object the overloaded NorthwindDataRetriever.GetData() method returns
    /// </summary>
    public class Categories
    {
        public int CategoryID;
        public string CategoryName;
        public string Description;
    }

    /// <summary>
    /// This is one of the classes that can be plugged into the List object the overloaded NorthwindDataRetriever.GetData() method returns
    /// </summary>
    public class ProductReorders
    {
        public int ProductID;
        public string ProductName;
        public decimal? UnitPrice;
        public string QuantityPerUnit;
        public int? UnitsInStock;
        public int? UnitsOnOrder;
        public int? ReorderLevel;
        public int SupplierID;
        public string SupplierName;
        public string ContactName;
        public string ContactPosition;
        public string ContactPhone;
    }

    /// <summary>
    /// This is one of the classes that can be plugged into the List object the overloaded NorthwindDataRetriever.GetData() method returns
    /// </summary>
    public class SupplierProducts
    {
        public int? SupplierID;
        public string SupplierName;
        public List<SupplierProduct> Products;
    }

    /// <summary>
    /// This class is plugged into the Products List in the SupplierProducts class
    /// </summary>
    public class SupplierProduct
    {
        public int ProductID;
        public string ProductName;
        public decimal? UnitPrice;
        public string QuantityPerUnit;
        public int? UnitsInStock;
        public int? UnitsOnOrder;
        public int? ReorderLevel;
    }
    
    /// <summary>
    /// This class accesses Microsoft's Northwind database through a RESTful service exposed by odata.org. ("NorthwindEntities" is the 
    /// top-level object exposed by Northwind.svc.)  The GetData method has three overloads, each taking a different type of List object 
    /// (defined above) as an out parameter. In each case, the method uses Linq to pull data into the List object.
    /// </summary>
    public class NorthwindDataRetriever
    {
        NorthwindEntities dc = new NorthwindEntities (new Uri("http://services.odata.org/Northwind/Northwind.svc"));
                
        /// <summary>
        /// This method gets a list of categories (using Linq method syntax).
        /// </summary>
        /// <returns></returns>
        public void GetData(out List<Categories> cList)
        {
            cList = dc.Categories.Select(c => new Categories 
            { 
                CategoryID = c.CategoryID, 
                CategoryName = c.CategoryName, 
                Description = c.Description 
            }
            ).ToList();
        }
        
        /// <summary>
        /// This method gets a list of products that need to be reordered (i. e. products whose reorder level exceeds the sum of units in
        /// stock and units on order). The result set includes contact info for the supplier, and is sorted by supplier.
        /// </summary>
        public void GetData(out List<ProductReorders> cList)
        {
            cList =
                (
                from p in dc.Products
                where p.UnitsOnOrder + p.UnitsInStock < p.ReorderLevel
                orderby p.Supplier.CompanyName, p.ProductName
                select new ProductReorders
                {
                    SupplierName = p.Supplier.CompanyName,
                    ContactName = p.Supplier.ContactName,
                    ContactPosition = p.Supplier.ContactTitle,
                    ContactPhone = p.Supplier.Phone,
                    ProductID = p.ProductID,
                    ProductName = p.ProductName,
                    UnitPrice = p.UnitPrice,
                    QuantityPerUnit = p.QuantityPerUnit,
                    UnitsInStock = p.UnitsInStock,
                    UnitsOnOrder = p.UnitsOnOrder,
                    ReorderLevel = p.ReorderLevel
                }
                ).ToList();
        }

        /// <summary>
        /// This method gets a list of suppliers and the products they sell. It preserves nesting for the products in the result set, i.e.
        /// each Supplier instance has a Products property which is a list of instances of all the products that supplier carries. (The 
        /// alternative is to "flatten" each Supplier instance, as in the GetProductReorders method above.)
        /// </summary>
        /// <returns></returns>
        public void GetData(out List<SupplierProducts> cList)
        {
            cList =
                (
                from s in dc.Suppliers
                select new SupplierProducts
                {
                    SupplierID = s.SupplierID,
                    SupplierName = s.CompanyName,
                    Products = 
                    (
                    from p in s.Products 
                    select new SupplierProduct
                    { 
                        ProductID = p.ProductID, 
                        ProductName = p.ProductName,
                        UnitPrice = p.UnitPrice,
                        QuantityPerUnit = p.QuantityPerUnit,
                        UnitsInStock = p.UnitsInStock,
                        UnitsOnOrder = p.UnitsOnOrder,
                        ReorderLevel = p.ReorderLevel
                    }
                    ).ToList()
                }
                ).ToList();
        }
    }
}

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using System;

using System.Collections.Generic;

using System.Linq;

// (To use the OData Northwind service, a service reference to "http://services.odata.org/Northwind/Northwind.svc/" must be included in

// the project.)

using NorthwindDataExporter.ODataNorthwindService;

namespace NorthwindDataRetrieve

{

/// <summary>

/// This is one of the classes that can be plugged into the List object the overloaded NorthwindDataRetriever.GetData() method returns

/// </summary>

public class Categories

{

public int CategoryID;

public string CategoryName;

public string Description;

}

/// <summary>

/// This is one of the classes that can be plugged into the List object the overloaded NorthwindDataRetriever.GetData() method returns

/// </summary>

public class ProductReorders

{

public int ProductID;

public string ProductName;

public decimal? UnitPrice;

public string QuantityPerUnit;

public int? UnitsInStock;

public int? UnitsOnOrder;

public int? ReorderLevel;

public int SupplierID;

public string SupplierName;

public string ContactName;

public string ContactPosition;

public string ContactPhone;

}

/// <summary>

/// This is one of the classes that can be plugged into the List object the overloaded NorthwindDataRetriever.GetData() method returns

/// </summary>

public class SupplierProducts

{

public int? SupplierID;

public string SupplierName;

public List<SupplierProduct> Products;

}

/// <summary>

/// This class is plugged into the Products List in the SupplierProducts class

/// </summary>

public class SupplierProduct

{

public int ProductID;

public string ProductName;

public decimal? UnitPrice;

public string QuantityPerUnit;

public int? UnitsInStock;

public int? UnitsOnOrder;

public int? ReorderLevel;

}

/// <summary>

/// This class accesses Microsoft's Northwind database through a RESTful service exposed by odata.org. ("NorthwindEntities" is the

/// top-level object exposed by Northwind.svc.) The GetData method has three overloads, each taking a different type of List object

/// (defined above) as an out parameter. In each case, the method uses Linq to pull data into the List object.

/// </summary>

public class NorthwindDataRetriever

{

NorthwindEntities dc = new NorthwindEntities (new Uri("http://services.odata.org/Northwind/Northwind.svc"));

/// <summary>

/// This method gets a list of categories (using Linq method syntax).

/// </summary>

/// <returns></returns>

public void GetData(out List<Categories> cList)

{

cList = dc.Categories.Select(c => new Categories

{

CategoryID = c.CategoryID,

CategoryName = c.CategoryName,

Description = c.Description

}

).ToList();

}

/// <summary>

/// This method gets a list of products that need to be reordered (i. e. products whose reorder level exceeds the sum of units in

/// stock and units on order). The result set includes contact info for the supplier, and is sorted by supplier.

/// </summary>

public void GetData(out List<ProductReorders> cList)

{

cList =

(

from p in dc.Products

where p.UnitsOnOrder + p.UnitsInStock < p.ReorderLevel

orderby p.Supplier.CompanyName, p.ProductName

select new ProductReorders

{

SupplierName = p.Supplier.CompanyName,

ContactName = p.Supplier.ContactName,

ContactPosition = p.Supplier.ContactTitle,

ContactPhone = p.Supplier.Phone,

ProductID = p.ProductID,

ProductName = p.ProductName,

UnitPrice = p.UnitPrice,

QuantityPerUnit = p.QuantityPerUnit,

UnitsInStock = p.UnitsInStock,

UnitsOnOrder = p.UnitsOnOrder,

ReorderLevel = p.ReorderLevel

}

).ToList();

}

/// <summary>

/// This method gets a list of suppliers and the products they sell. It preserves nesting for the products in the result set, i.e.

/// each Supplier instance has a Products property which is a list of instances of all the products that supplier carries. (The

/// alternative is to "flatten" each Supplier instance, as in the GetProductReorders method above.)

/// </summary>

/// <returns></returns>

public void GetData(out List<SupplierProducts> cList)

{

cList =

(

from s in dc.Suppliers

select new SupplierProducts

{

SupplierID = s.SupplierID,

SupplierName = s.CompanyName,

Products =

(

from p in s.Products

select new SupplierProduct

{

ProductID = p.ProductID,

ProductName = p.ProductName,

UnitPrice = p.UnitPrice,

QuantityPerUnit = p.QuantityPerUnit,

UnitsInStock = p.UnitsInStock,

UnitsOnOrder = p.UnitsOnOrder,

ReorderLevel = p.ReorderLevel

}

).ToList()

}

).ToList();

}

DataExport.cs


using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Xml.Serialization;
using System.IO;
using System.Web.Script.Serialization;
using NorthwindDataRetrieve;
using ConsoleClient;

namespace DataExport
{
    /// <summary>
    /// This abstract class derives from EventArgs, and also defines two additional custom event arguments that will be passed to a 
    /// DataExporterEvent delegate.
    /// </summary>
    public abstract class aDEEventArgs:EventArgs
    {
        abstract public int ExportStatus { get; }
        abstract public string ReturnMessage { get; }
        abstract public string FileName { get; }
    }

    /// <summary>
    /// This is the delegate that defines the signature of the DataExporterEvent Event. The definition implicitly stipulates that any class
    /// using it must implement the iDataExporter interface, and also that such a class must implement the aDEEventArgs abstract class.
    /// </summary>
    public delegate void DataExporterEvent(iDataExporter sender, aDEEventArgs deargs);

    /// <summary>
    /// The main interface. This interface defines an event of type DataExporterEvent, which in turn specifies an aDEEventArgs type for one 
    /// of its arguments.
    /// </summary>
    public interface iDataExporter
    {
        void Export<T>(List<T> exportList, string filePath, FileType fileType) where T: class;
        event DataExporterEvent OnExportFinished;
    }

    /// <summary>
    /// This class implements aDEEventArgs, thus providing the ExportStatus and FileName arguments to an event 
    /// handler. Properties are read only, being passed as initial values in the constructor.
    /// </summary>
    public class DEEventArgs: aDEEventArgs
    {
        private int es;
        private string rmsg;
        private string fname;

        //Overriding the default constructor to require two arguments as stipulated in the aDEEventArgs abstract class.
        public DEEventArgs (int exportStatus, string returnMessage, string fileName)
        {
            es = exportStatus;
            rmsg = returnMessage;
            fname = fileName;
        }
 
        //Implementing the two arguments defined in the aDEEventArgs abstract class.
        public override int ExportStatus
        {
            get { return es; }
        }

        public override string ReturnMessage
        {
            get { return rmsg; }
        }
        
        public override string FileName
        {
            get { return fname; }
        }
    }

    /// <summary>
    /// This class is implemented as a singleton. Although technically it isn't necessary here to make the class sealed for it to be 
    /// a singleton (we're not going to derive any classes from it anyway), derived classes could be instantiated and thereby break 
    /// the singleton pattern. Therefore best practice is to make the class sealed.
    /// </summary>
    public sealed class DataExporter : iDataExporter
    {
        private static readonly DataExporter instance = new DataExporter();  //Holds a private reference to the singleton instance.
        public event DataExporterEvent OnExportFinished;

        /// <summary>
        /// Overriding the default constructor to make it private. Doing this has the effect of requiring instantiation via a method
        /// (as opposed to using the new keyword), in this case the Instance property accessor method.
        /// </summary>
        private DataExporter() { }
          
        /// <summary>
        /// Making the Instance property static has the de facto effect of implementing the singleton pattern, since there is only one 
        /// instance of the object. Thread safety is guaranteed by the CLR. This is simpler than the more specific "roll your own" 
        /// version of singleton pattern implementation, which requires locks to be thread safe.
        /// </summary>        
        public static DataExporter Instance
        {
            get { return instance; }
        }
        
        /// <summary>
        /// The Export method is a generic method, allowing it to accept List objects of any type as a parameter. The "class"
        /// constraint restricts lists to lists of objects (as opposed to strings or structs, for example).
        /// </summary>
        public void Export<T>(List<T> exportList, string filePath, FileType fileType) where T: class
        {
            try
            {
                switch (fileType)
                {
                    case FileType.JSON:
                        var json = new JavaScriptSerializer().Serialize(exportList);
                        File.WriteAllText(filePath, json);
                        break;
                    case FileType.XML:
                        XmlSerializer serializer = new XmlSerializer(exportList.GetType());
                        using (TextWriter writer = new StreamWriter(filePath))
                        { serializer.Serialize(writer, exportList); }
                        break;
                    default:
                        throw new Exception("Error that *should* never occur; since we're using an enum, any code that could hit it won't
                            compile");
                }
                DEEventArgs deargs = new DEEventArgs(1, "", filePath);
                if (null != OnExportFinished) { OnExportFinished(this, deargs); }
            }
            catch (IOException ex) 
            {
                DEEventArgs deargs = new DEEventArgs(0, ex.Message, filePath);
                if (null != OnExportFinished) { OnExportFinished(this, deargs); }
            }
            catch (Exception ex) 
            {
                DEEventArgs deargs = new DEEventArgs(0, "Unhandled Error: " + ex.Message, filePath);
                if (null != OnExportFinished) { OnExportFinished(this, deargs); }
            }
        }
    }
}

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using System;

using System.Collections.Generic;

using System.Text;

using System.Data;

using System.Xml.Serialization;

using System.IO;

using System.Web.Script.Serialization;

using NorthwindDataRetrieve;

using ConsoleClient;

namespace DataExport

{

/// <summary>

/// This abstract class derives from EventArgs, and also defines two additional custom event arguments that will be passed to a

/// DataExporterEvent delegate.

/// </summary>

public abstract class aDEEventArgs:EventArgs

{

abstract public int ExportStatus { get; }

abstract public string ReturnMessage { get; }

abstract public string FileName { get; }

}

/// <summary>

/// This is the delegate that defines the signature of the DataExporterEvent Event. The definition implicitly stipulates that any class

/// using it must implement the iDataExporter interface, and also that such a class must implement the aDEEventArgs abstract class.

/// </summary>

public delegate void DataExporterEvent(iDataExporter sender, aDEEventArgs deargs);

/// <summary>

/// The main interface. This interface defines an event of type DataExporterEvent, which in turn specifies an aDEEventArgs type for one

/// of its arguments.

/// </summary>

public interface iDataExporter

{

void Export<T>(List<T> exportList, string filePath, FileType fileType) where T: class;

event DataExporterEvent OnExportFinished;

}

/// <summary>

/// This class implements aDEEventArgs, thus providing the ExportStatus and FileName arguments to an event

/// handler. Properties are read only, being passed as initial values in the constructor.

/// </summary>

public class DEEventArgs: aDEEventArgs

{

private int es;

private string rmsg;

private string fname;

//Overriding the default constructor to require two arguments as stipulated in the aDEEventArgs abstract class.

public DEEventArgs (int exportStatus, string returnMessage, string fileName)

{

es = exportStatus;

rmsg = returnMessage;

fname = fileName;

}

//Implementing the two arguments defined in the aDEEventArgs abstract class.

public override int ExportStatus

{

get { return es; }

}

public override string ReturnMessage

{

get { return rmsg; }

}

public override string FileName

{

get { return fname; }

}

/// <summary>

/// This class is implemented as a singleton. Although technically it isn't necessary here to make the class sealed for it to be

/// a singleton (we're not going to derive any classes from it anyway), derived classes could be instantiated and thereby break

/// the singleton pattern. Therefore best practice is to make the class sealed.

/// </summary>

public sealed class DataExporter : iDataExporter

{

private static readonly DataExporter instance = new DataExporter(); //Holds a private reference to the singleton instance.

public event DataExporterEvent OnExportFinished;

/// <summary>

/// Overriding the default constructor to make it private. Doing this has the effect of requiring instantiation via a method

/// (as opposed to using the new keyword), in this case the Instance property accessor method.

/// </summary>

private DataExporter() { }

/// <summary>

/// Making the Instance property static has the de facto effect of implementing the singleton pattern, since there is only one

/// instance of the object. Thread safety is guaranteed by the CLR. This is simpler than the more specific "roll your own"

/// version of singleton pattern implementation, which requires locks to be thread safe.

/// </summary>

public static DataExporter Instance

{

get { return instance; }

}

/// <summary>

/// The Export method is a generic method, allowing it to accept List objects of any type as a parameter. The "class"

/// constraint restricts lists to lists of objects (as opposed to strings or structs, for example).

/// </summary>

public void Export<T>(List<T> exportList, string filePath, FileType fileType) where T: class

{

try

{

switch (fileType)

{

case FileType.JSON:

var json = new JavaScriptSerializer().Serialize(exportList);

File.WriteAllText(filePath, json);

break;

case FileType.XML:

XmlSerializer serializer = new XmlSerializer(exportList.GetType());

using (TextWriter writer = new StreamWriter(filePath))

{ serializer.Serialize(writer, exportList); }

break;

default:

throw new Exception("Error that *should* never occur; since we're using an enum, any code that could hit it won't

compile");

}

DEEventArgs deargs = new DEEventArgs(1, "", filePath);

if (null != OnExportFinished) { OnExportFinished(this, deargs); }

}

catch (IOException ex)

{

DEEventArgs deargs = new DEEventArgs(0, ex.Message, filePath);

if (null != OnExportFinished) { OnExportFinished(this, deargs); }

}

catch (Exception ex)

{

DEEventArgs deargs = new DEEventArgs(0, "Unhandled Error: " + ex.Message, filePath);

if (null != OnExportFinished) { OnExportFinished(this, deargs); }

}

Collapse

VB.Net: Multithreading, Using a RESTful Service

This code sample is the functional equivalent, written in VB, of the code in the preceding C# sample. The comments here are limited to those which do not apply to both samples. For full comments, please refer to the C# sample.

Expand

This code sample is the functional equivalent, written in VB, of the code in the C# sample. The comments here are limited to those which do not apply to both samples. For full comments, please refer to the C# sample.

Program.vb


' Option Strict On results in a compiler error in the doWork method. See the notes there for further explanation.

Option Explicit On
Option Infer On
Imports System.Threading
Imports System.Reflection
Imports NorthwindDataExporter.DataExport
Imports NorthwindDataExporter.NorthwindDataRetrieve

Public Enum FileType
    JSON
    XML
End Enum

Module Program
    Class ThreadParams
        Private _filePath As String
        Private _fileType As Byte
        Private _listType As IEnumerable(Of Object)

        Public Sub New(filePath As String, fileType As FileType, listType As IEnumerable(Of Object))
            _filePath = filePath
            _fileType = fileType
            _listType = listType
        End Sub

        Public ReadOnly Property filePath As String
            Get
                Return _filePath
            End Get
        End Property

        Public ReadOnly Property fileType As Byte
            Get
                Return _fileType
            End Get
        End Property

        Public ReadOnly Property listType As IEnumerable(Of Object)
            Get
                Return _listType
            End Get
        End Property
    End Class

    Sub Main()
        Dim p As ThreadParams() =
        {
            New ThreadParams("c:Temp2CategoriesJSON.txt", FileType.JSON, New List(Of Categories)),
            New ThreadParams("c:Temp2SuppliersXML.txt", FileType.XML, New List(Of ProductReorders)),
            New ThreadParams("c:Temp2SuppliersJSON.txt", FileType.JSON, New List(Of SupplierProducts))
        }

        Dim t(2) As Thread

        For i As Integer = 0 To 2
            t(i) = New Thread(New ParameterizedThreadStart(AddressOf DoWork))
            With t(i)
                .Name = "Thread " & i.ToString
                .Start(p(i))
                .Join()
            End With
        Next

        Console.WriteLine("strike a key when ready...")
        Console.ReadKey(True)
    End Sub

    Private Sub DoWork(parms As Object)
        Try
            If Not TypeOf parms Is ThreadParams Then
                Throw New ArgumentException(Thread.CurrentThread.Name + ": Argument passed on thread start is not of type ThreadParams; thread aborted")
            End If

            Dim p As ThreadParams = CType(parms, ThreadParams)
            Dim de As DataExport.DataExporter = DataExporter.Instance
            Dim cRet As New NorthwindDataRetriever

            Dim cMethod As MethodBase = cRet.GetType().GetMethod("GetData", New Type() {parms.listType.GetType().MakeByRefType()})
            Dim cArgs(0) As Object
            cMethod.Invoke(cRet, cArgs)

            AddHandler de.OnExportFinished, AddressOf de_OnExportFinished

            'Option Strict On won't allow this line to compile. The Invoke method signature requires an argument 
            'of type System.Object(). Here, the Export method is looking for a List(Of T), which results in 
            'a narrowing conversion. (Base to derived is narrowing, because the base class only supports a 
            'subset of the interface that the derived class supports.)  The requirement here is to implicitly 
            'recast cArgs(0) to List(Of T) (all possible values of parms.listType return such). We can't 
            'explicitly recast cArgs(0) in code because we don't know until runtime exactly which sort of T was 
            'passed into the current thread parameter.

            de.Export(cArgs(0), p.filePath, p.fileType)

            RemoveHandler de.OnExportFinished, AddressOf de_OnExportFinished
        Catch ex As NullReferenceException
            Console.WriteLine("Null Reference Exception in " + Thread.CurrentThread.Name + ": " + ex.Message +
                              " (probable cause is incorrect object type in thread's listType parameter)")
            Exit Sub
        Catch ex As ArgumentException
            Console.WriteLine(ex.Message)
        Catch ex As Exception
            Console.WriteLine("Unhandled Exception: " & ex.Message)
        End Try
    End Sub

    Private Sub de_OnExportFinished(sender As iDataExporter, deArgs As aDEEventArgs)
        Select Case deArgs.ExportStatus
            Case 0
                Console.WriteLine("Export routine for " + Thread.CurrentThread.Name + " failed with this error: " + deArgs.ReturnMessage)
            Case Else
                Console.WriteLine("Export to " + deArgs.FileName + " successful using " + Thread.CurrentThread.Name)
        End Select
    End Sub

End Module

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' Option Strict On results in a compiler error in the doWork method. See the notes there for further explanation.

Option Explicit On

Option Infer On

Imports System.Threading

Imports System.Reflection

Imports NorthwindDataExporter.DataExport

Imports NorthwindDataExporter.NorthwindDataRetrieve

Public Enum FileType

JSON

XML

End Enum

Module Program

Class ThreadParams

Private _filePath As String

Private _fileType As Byte

Private _listType As IEnumerable(Of Object)

Public Sub New(filePath As String, fileType As FileType, listType As IEnumerable(Of Object))

_filePath = filePath

_fileType = fileType

_listType = listType

End Sub

Public ReadOnly Property filePath As String

Get

Return _filePath

End Get

End Property

Public ReadOnly Property fileType As Byte

Get

Return _fileType

End Get

End Property

Public ReadOnly Property listType As IEnumerable(Of Object)

Get

Return _listType

End Get

End Property

End Class

Sub Main()

Dim p As ThreadParams() =

{

New ThreadParams("c:Temp2CategoriesJSON.txt", FileType.JSON, New List(Of Categories)),

New ThreadParams("c:Temp2SuppliersXML.txt", FileType.XML, New List(Of ProductReorders)),

New ThreadParams("c:Temp2SuppliersJSON.txt", FileType.JSON, New List(Of SupplierProducts))

}

Dim t(2) As Thread

For i As Integer = 0 To 2

t(i) = New Thread(New ParameterizedThreadStart(AddressOf DoWork))

With t(i)

.Name = "Thread " & i.ToString

.Start(p(i))

.Join()

End With

Console.WriteLine("strike a key when ready...")

Console.ReadKey(True)

End Sub

Private Sub DoWork(parms As Object)

Try

If Not TypeOf parms Is ThreadParams Then

Throw New ArgumentException(Thread.CurrentThread.Name + ": Argument passed on thread start is not of type ThreadParams; thread aborted")

End If

Dim p As ThreadParams = CType(parms, ThreadParams)

Dim de As DataExport.DataExporter = DataExporter.Instance

Dim cRet As New NorthwindDataRetriever

Dim cMethod As MethodBase = cRet.GetType().GetMethod("GetData", New Type() {parms.listType.GetType().MakeByRefType()})

Dim cArgs(0) As Object

cMethod.Invoke(cRet, cArgs)

AddHandler de.OnExportFinished, AddressOf de_OnExportFinished

'Option Strict On won't allow this line to compile. The Invoke method signature requires an argument

'of type System.Object(). Here, the Export method is looking for a List(Of T), which results in

'a narrowing conversion. (Base to derived is narrowing, because the base class only supports a

'subset of the interface that the derived class supports.) The requirement here is to implicitly

'recast cArgs(0) to List(Of T) (all possible values of parms.listType return such). We can't

'explicitly recast cArgs(0) in code because we don't know until runtime exactly which sort of T was

'passed into the current thread parameter.

de.Export(cArgs(0), p.filePath, p.fileType)

RemoveHandler de.OnExportFinished, AddressOf de_OnExportFinished

Catch ex As NullReferenceException

Console.WriteLine("Null Reference Exception in " + Thread.CurrentThread.Name + ": " + ex.Message +

" (probable cause is incorrect object type in thread's listType parameter)")

Exit Sub

Catch ex As ArgumentException

Console.WriteLine(ex.Message)

Catch ex As Exception

Console.WriteLine("Unhandled Exception: " & ex.Message)

End Try

End Sub

Private Sub de_OnExportFinished(sender As iDataExporter, deArgs As aDEEventArgs)

Select Case deArgs.ExportStatus

Case 0

Console.WriteLine("Export routine for " + Thread.CurrentThread.Name + " failed with this error: " + deArgs.ReturnMessage)

Case Else

Console.WriteLine("Export to " + deArgs.FileName + " successful using " + Thread.CurrentThread.Name)

End Select

End Sub

End Module

NorthwindDataRetrieve.vb


Option Strict On
Imports NorthwindDataExporter.ODataNorthwindService

Namespace NorthwindDataRetrieve

    Public Class Categories
        Public CategoryID As Integer
        Public CategoryName As String
        Public Description As String
    End Class

    Public Class ProductReorders
        Public ProductID As Integer
        Public ProductName As String
        Public UnitPrice As Decimal
        Public QuantityPerUnit As String
        Public UnitsInStock As Integer
        Public UnitsOnOrder As Integer
        Public ReorderLevel As Integer
        Public SupplierID As Integer
        Public SupplierName As String
        Public ContactName As String
        Public ContactPosition As String
        Public ContactPhone As String
    End Class

    Public Class SupplierProducts
        Public SupplierID As Integer
        Public SupplierName As String
        Public Products As List(Of SupplierProduct)
    End Class

    Public Class SupplierProduct
        Public ProductID As Integer
        Public ProductName As String
        Public UnitPrice As Decimal
        Public QuantityPerUnit As String
        Public UnitsInStock As Integer
        Public UnitsOnOrder As Integer
        Public ReorderLevel As Integer
    End Class

    Public Class NorthwindDataRetriever

        Dim dc As New NorthwindEntities(New Uri("http://services.odata.org/Northwind/Northwind.svc/"))

        Public Sub GetData(ByRef cList As List(Of Categories))
            cList = dc.Categories.Select(Function(c As Category) New Categories With
                {
                    .CategoryID = c.CategoryID,
                    .CategoryName = c.CategoryName,
                    .Description = c.Description
                }
                ).ToList()
        End Sub

        Public Sub GetData(ByRef cList As List(Of ProductReorders))
            cList =
                (
                From p In dc.Products
                Where p.UnitsOnOrder + p.UnitsInStock < p.ReorderLevel
                Order By p.Supplier.CompanyName, p.ProductName
                Select New ProductReorders With
                {
                    .SupplierName = p.Supplier.CompanyName,
                    .ContactName = p.Supplier.ContactName,
                    .ContactPosition = p.Supplier.ContactTitle,
                    .ContactPhone = p.Supplier.Phone,
                    .ProductID = p.ProductID,
                    .ProductName = p.ProductName,
                    .UnitPrice = CDec(p.UnitPrice),
                    .QuantityPerUnit = p.QuantityPerUnit,
                    .UnitsInStock = CInt(p.UnitsInStock),
                    .UnitsOnOrder = CInt(p.UnitsOnOrder),
                    .ReorderLevel = CInt(p.ReorderLevel)
                }
                ).ToList()
        End Sub

        Public Sub GetData(ByRef cList As List(Of SupplierProducts))
            cList =
                (
                From s In dc.Suppliers
                Select New SupplierProducts With
                {
                    .SupplierID = s.SupplierID,
                    .SupplierName = s.CompanyName,
                    .Products =
                    (
                    From p In s.Products
                    Select New SupplierProduct With
                    {
                        .ProductID = p.ProductID,
                        .ProductName = p.ProductName,
                        .UnitPrice = CDec(p.UnitPrice),
                        .QuantityPerUnit = p.QuantityPerUnit,
                        .UnitsInStock = CInt(p.UnitsInStock),
                        .UnitsOnOrder = CInt(p.UnitsOnOrder),
                        .ReorderLevel = CInt(p.ReorderLevel)
                    }
                    ).ToList()
                }
                ).ToList()

        End Sub
    End Class
End Namespace

100

101

102

103

104

105

106

107

108

109

Option Strict On

Imports NorthwindDataExporter.ODataNorthwindService

Namespace NorthwindDataRetrieve

Public Class Categories

Public CategoryID As Integer

Public CategoryName As String

Public Description As String

End Class

Public Class ProductReorders

Public ProductID As Integer

Public ProductName As String

Public UnitPrice As Decimal

Public QuantityPerUnit As String

Public UnitsInStock As Integer

Public UnitsOnOrder As Integer

Public ReorderLevel As Integer

Public SupplierID As Integer

Public SupplierName As String

Public ContactName As String

Public ContactPosition As String

Public ContactPhone As String

End Class

Public Class SupplierProducts

Public SupplierID As Integer

Public SupplierName As String

Public Products As List(Of SupplierProduct)

End Class

Public Class SupplierProduct

Public ProductID As Integer

Public ProductName As String

Public UnitPrice As Decimal

Public QuantityPerUnit As String

Public UnitsInStock As Integer

Public UnitsOnOrder As Integer

Public ReorderLevel As Integer

End Class

Public Class NorthwindDataRetriever

Dim dc As New NorthwindEntities(New Uri("http://services.odata.org/Northwind/Northwind.svc/"))

Public Sub GetData(ByRef cList As List(Of Categories))

cList = dc.Categories.Select(Function(c As Category) New Categories With

{

.CategoryID = c.CategoryID,

.CategoryName = c.CategoryName,

.Description = c.Description

}

).ToList()

End Sub

Public Sub GetData(ByRef cList As List(Of ProductReorders))

cList =

(

From p In dc.Products

Where p.UnitsOnOrder + p.UnitsInStock < p.ReorderLevel

Order By p.Supplier.CompanyName, p.ProductName

Select New ProductReorders With

{

.SupplierName = p.Supplier.CompanyName,

.ContactName = p.Supplier.ContactName,

.ContactPosition = p.Supplier.ContactTitle,

.ContactPhone = p.Supplier.Phone,

.ProductID = p.ProductID,

.ProductName = p.ProductName,

.UnitPrice = CDec(p.UnitPrice),

.QuantityPerUnit = p.QuantityPerUnit,

.UnitsInStock = CInt(p.UnitsInStock),

.UnitsOnOrder = CInt(p.UnitsOnOrder),

.ReorderLevel = CInt(p.ReorderLevel)

}

).ToList()

End Sub

Public Sub GetData(ByRef cList As List(Of SupplierProducts))

cList =

(

From s In dc.Suppliers

Select New SupplierProducts With

{

.SupplierID = s.SupplierID,

.SupplierName = s.CompanyName,

.Products =

(

From p In s.Products

Select New SupplierProduct With

{

.ProductID = p.ProductID,

.ProductName = p.ProductName,

.UnitPrice = CDec(p.UnitPrice),

.QuantityPerUnit = p.QuantityPerUnit,

.UnitsInStock = CInt(p.UnitsInStock),

.UnitsOnOrder = CInt(p.UnitsOnOrder),

.ReorderLevel = CInt(p.ReorderLevel)

}

).ToList()

}

).ToList()

End Sub

End Class

End Namespace

DataExport.vb


Option Strict On
Imports System.Xml.Serialization
Imports System.IO
Imports System.Web.Script.Serialization

Namespace DataExport

    Public Delegate Sub DataExporterEvent(sender As iDataExporter, deArgs As aDEEventArgs)

    Public Interface iDataExporter
        Sub Export(Of T As Class)(exportList As List(Of T), filePath As String, fileType As FileType)
        Event OnExportFinished As DataExporterEvent
    End Interface

    Public MustInherit Class aDEEventArgs
        Inherits EventArgs
        Public MustOverride ReadOnly Property ExportStatus() As Integer
        Public MustOverride ReadOnly Property ReturnMessage() As String
        Public MustOverride ReadOnly Property FileName() As String
    End Class

    Public Class DEEventArgs
        Inherits aDEEventArgs
        Private es As Integer
        Private rMsg As String
        Private fName As String

        Public Sub New(ExportStatus As Integer, ReturnMessage As String, FileName As String)
            es = ExportStatus
            rMsg = ReturnMessage
            fName = FileName
        End Sub

        Public Overrides ReadOnly Property ExportStatus As Integer
            Get
                Return es
            End Get
        End Property

        Public Overrides ReadOnly Property ReturnMessage As String
            Get
                Return rMsg
            End Get
        End Property

        Public Overrides ReadOnly Property FileName As String
            Get
                Return fName
            End Get
        End Property
    End Class

    Public NotInheritable Class DataExporter
        Implements iDataExporter
        Private Shared _instance As New DataExporter
        Public Event OnExportFinished As DataExporterEvent Implements iDataExporter.OnExportFinished

        Private Sub New()
            'Override the default constructor to make it private
        End Sub

        Public Shared ReadOnly Property Instance() As DataExporter
            Get
                Return _instance
            End Get
        End Property

        Sub Export(Of T As Class)(exportList As List(Of T), filePath As String, fileType As FileType) Implements iDataExporter.Export
            Try
                Select Case fileType
                    Case fileType.JSON
                        Dim json As String
                        With New JavaScriptSerializer
                            json = .Serialize(exportList)
                        End With
                        File.WriteAllText(filePath, json)
                    Case fileType.XML
                        Dim serializer As New XmlSerializer(exportList.GetType())
                        Using writer As TextWriter = New StreamWriter(filePath)
                            serializer.Serialize(writer, exportList)
                        End Using
                    Case Else
                        Throw New Exception("FileType object fileType is improperly defined")
                End Select
                Dim deArgs As New DEEventArgs(1, "", filePath)
                RaiseEvent OnExportFinished(Me, deArgs)
            Catch ex As IOException
                Dim deArgs As New DEEventArgs(0, ex.Message, filePath)
                RaiseEvent OnExportFinished(Me, deArgs)
            Catch ex As Exception
                Dim deArgs As New DEEventArgs(0, "Unhandled Error: " & ex.Message, filePath)
                RaiseEvent OnExportFinished(Me, deArgs)
            End Try
        End Sub
    End Class
End Namespace

Option Strict On

Imports System.Xml.Serialization

Imports System.IO

Imports System.Web.Script.Serialization

Namespace DataExport

Public Delegate Sub DataExporterEvent(sender As iDataExporter, deArgs As aDEEventArgs)

Public Interface iDataExporter

Sub Export(Of T As Class)(exportList As List(Of T), filePath As String, fileType As FileType)

Event OnExportFinished As DataExporterEvent

End Interface

Public MustInherit Class aDEEventArgs

Inherits EventArgs

Public MustOverride ReadOnly Property ExportStatus() As Integer

Public MustOverride ReadOnly Property ReturnMessage() As String

Public MustOverride ReadOnly Property FileName() As String

End Class

Public Class DEEventArgs

Inherits aDEEventArgs

Private es As Integer

Private rMsg As String

Private fName As String

Public Sub New(ExportStatus As Integer, ReturnMessage As String, FileName As String)

es = ExportStatus

rMsg = ReturnMessage

fName = FileName

End Sub

Public Overrides ReadOnly Property ExportStatus As Integer

Get

Return es

End Get

End Property

Public Overrides ReadOnly Property ReturnMessage As String

Get

Return rMsg

End Get

End Property

Public Overrides ReadOnly Property FileName As String

Get

Return fName

End Get

End Property

End Class

Public NotInheritable Class DataExporter

Implements iDataExporter

Private Shared _instance As New DataExporter

Public Event OnExportFinished As DataExporterEvent Implements iDataExporter.OnExportFinished

Private Sub New()

'Override the default constructor to make it private

End Sub

Public Shared ReadOnly Property Instance() As DataExporter

Get

Return _instance

End Get

End Property

Sub Export(Of T As Class)(exportList As List(Of T), filePath As String, fileType As FileType) Implements iDataExporter.Export

Try

Select Case fileType

Case fileType.JSON

Dim json As String

With New JavaScriptSerializer

json = .Serialize(exportList)

End With

File.WriteAllText(filePath, json)

Case fileType.XML

Dim serializer As New XmlSerializer(exportList.GetType())

Using writer As TextWriter = New StreamWriter(filePath)

serializer.Serialize(writer, exportList)

End Using

Case Else

Throw New Exception("FileType object fileType is improperly defined")

End Select

Dim deArgs As New DEEventArgs(1, "", filePath)

RaiseEvent OnExportFinished(Me, deArgs)

Catch ex As IOException

Dim deArgs As New DEEventArgs(0, ex.Message, filePath)

RaiseEvent OnExportFinished(Me, deArgs)

Catch ex As Exception

Dim deArgs As New DEEventArgs(0, "Unhandled Error: " & ex.Message, filePath)

RaiseEvent OnExportFinished(Me, deArgs)

End Try

End Sub

End Class

End Namespace

Collapse

T-SQL: Various Examples

T-SQL examples, including transactions, dynamic SQL and various utilities.

Expand

T-SQL examples, including transactions, dynamic SQL and various utilities.

List all the tables and columns in the current database.


SELECT DISTINCT
            tb.name 'Table'
        FROM    
            sys.columns c
            join sys.tables tb on tb.object_id = c.object_id
        INNER JOIN 
            sys.types t ON c.user_type_id = t.user_type_id
        LEFT OUTER JOIN 
            sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id
        LEFT OUTER JOIN 
            sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id
        ORDER BY tb.name

SELECT DISTINCT

tb.name 'Table'

FROM

sys.columns c

join sys.tables tb on tb.object_id = c.object_id

INNER JOIN

sys.types t ON c.user_type_id = t.user_type_id

LEFT OUTER JOIN

sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id

LEFT OUTER JOIN

sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id

ORDER BY tb.name

Run a group of (parameterless) stored procedures one after the other (in this case, a series of daily merge procs).


--
        DECLARE @temp0 TABLE
        (
            [ID] [int] IDENTITY(1,1) NOT NULL,
            [Name] [varchar](max) NULL
        )
        
        INSERT INTO @temp0 SELECT Name FROM sys.procedures WHERE NAME LIKE 'usp_merge_%'
        
        DECLARE @spName varchar(max)
        DECLARE @Loops INT
        DECLARE @X INT
        DECLARE    @return_value int
        
        SET @Loops = (SELECT COUNT(*) cnt FROM @temp0)
        SET @X = 1
        
        WHILE @X <= @Loops
        BEGIN
            SET @spName = (SELECT Name FROM @temp0 WHERE ID = @x)
            EXEC @return_value = @spName
            SELECT 'Return Value' = @return_value, 'Name' = @spName
            SET @X = @X + 1
        END

DECLARE @temp0 TABLE

(

[ID] [int] IDENTITY(1,1) NOT NULL,

[Name] [varchar](max) NULL

)

INSERT INTO @temp0 SELECT Name FROM sys.procedures WHERE NAME LIKE 'usp_merge_%'

DECLARE @spName varchar(max)

DECLARE @Loops INT

DECLARE @X INT

DECLARE @return_value int

SET @Loops = (SELECT COUNT(*) cnt FROM @temp0)

SET @X = 1

WHILE @X <= @Loops

BEGIN

SET @spName = (SELECT Name FROM @temp0 WHERE ID = @x)

EXEC @return_value = @spName

SELECT 'Return Value' = @return_value, 'Name' = @spName

SET @X = @X + 1

END

Pull data from a list of by-the-minute inspection results, roll them up on a per-hour basis, and pivot the results based on inspection type.


SELECT ProcessDate, [Abnormality], [ILX], [Balancer] INTO DataByHour FROM 
            (
                SELECT DISTINCT ProcessDate, ProcessType, COUNT(ProcessDate) AS TiresProcessed FROM
                    (
                        SELECT [MachineID]
                            --Pulls data rolled up by hour (Adding 30 mins has the effect of rounding to nearest hour)
                            ,DATEADD(HOUR, DATEDIFF(HOUR, 0, DATEADD(MI, 30, [ProcessDate])), 0) AS ProcessDate  
                            --,DATEADD(DAY, DATEDIFF(DAY, 0, [ProcessDate]), 0) AS ProcessDate  --This one will pull data rolled up by day
                            ,[ProcessResult]                                                                         
                            ,[ProcessType]
                        FROM [Final].[dbo].[vw_InspectionResults]
                        WHERE ProcessDate > '09/11/2014'
                    ) AS X
                GROUP BY ProcessDate, processtype
            ) AS Y
        PIVOT (SUM(TiresProcessed) FOR ProcessType IN ([Abnormality], [ILX], [Balancer])) AS Z

SELECT ProcessDate, [Abnormality], [ILX], [Balancer] INTO DataByHour FROM

(

SELECT DISTINCT ProcessDate, ProcessType, COUNT(ProcessDate) AS TiresProcessed FROM

(

SELECT [MachineID]

--Pulls data rolled up by hour (Adding 30 mins has the effect of rounding to nearest hour)

,DATEADD(HOUR, DATEDIFF(HOUR, 0, DATEADD(MI, 30, [ProcessDate])), 0) AS ProcessDate

--,DATEADD(DAY, DATEDIFF(DAY, 0, [ProcessDate]), 0) AS ProcessDate --This one will pull data rolled up by day

,[ProcessResult]

,[ProcessType]

FROM [Final].[dbo].[vw_InspectionResults]

WHERE ProcessDate > '09/11/2014'

) AS X

GROUP BY ProcessDate, processtype

) AS Y

PIVOT (SUM(TiresProcessed) FOR ProcessType IN ([Abnormality], [ILX], [Balancer])) AS Z

Use a transaction and dynamic SQL to perform an atomic read/write operation


/*
        This stored procedure accepts a comma-separated list of hospitalids as a string, finds the lowest available internalid value in the hospid_intid table, updates (in the hospid_intid table) each hospitalid in the string with the new internalid, and outputs the new internalid to the calling procedure. 
        
        The read and update need to be atomic, so they are enclosed in a transaction. We also need a guaranteed clean read. Since TRAN default behavior is to allow dirty reads and disallow dirty writes, we have to lock the hospid_intid table for the duration of the transaction.
        
        After finding the lowest available internalid value, the procedure plugs the resulting number into the update query and uses dynamic SQL to execute it.
        */
        
        CREATE PROCEDURE [dbo].[UpdateInternalId] @HospitalList varchar(MAX), @InternalID int OUT
        AS
        
        SET NOCOUNT ON
        
        DECLARE @SQL varchar(MAX)
        
        SET XACT_ABORT ON
        BEGIN TRAN
            SELECT @InternalID =  
                (
                    SELECT TOP 1 a.internalid + 1
                    FROM hospid_intid a
                    WITH (tablockx, holdlock) --Lock the table 
                    WHERE NOT EXISTS
                        (
                            SELECT 1 
                            FROM hospid_intid b 
                            WHERE b.internalid = a.internalid + 1 
                        )
                    ORDER BY a.internalid
                )
            SET @SQL = 
                'UPDATE hospid_intid SET internalid = ' 
                + Convert(VarChar(10), @InternalID)
                +'WHERE hospitalid IN (' + @HospitalList + ')'
            EXEC (@SQL)
        COMMIT TRAN
        SET XACT_ABORT OFF

This stored procedure accepts a comma-separated list of hospitalids as a string, finds the lowest available internalid value in the hospid_intid table, updates (in the hospid_intid table) each hospitalid in the string with the new internalid, and outputs the new internalid to the calling procedure.

The read and update need to be atomic, so they are enclosed in a transaction. We also need a guaranteed clean read. Since TRAN default behavior is to allow dirty reads and disallow dirty writes, we have to lock the hospid_intid table for the duration of the transaction.

After finding the lowest available internalid value, the procedure plugs the resulting number into the update query and uses dynamic SQL to execute it.

CREATE PROCEDURE [dbo].[UpdateInternalId] @HospitalList varchar(MAX), @InternalID int OUT

SET NOCOUNT ON

DECLARE @SQL varchar(MAX)

SET XACT_ABORT ON

BEGIN TRAN

SELECT @InternalID =

(

SELECT TOP 1 a.internalid + 1

FROM hospid_intid a

WITH (tablockx, holdlock) --Lock the table

WHERE NOT EXISTS

(

SELECT 1

FROM hospid_intid b

WHERE b.internalid = a.internalid + 1

)

ORDER BY a.internalid

)

SET @SQL =

'UPDATE hospid_intid SET internalid = '

+ Convert(VarChar(10), @InternalID)

+'WHERE hospitalid IN (' + @HospitalList + ')'

EXEC (@SQL)

COMMIT TRAN

SET XACT_ABORT OFF

List all reports in SSRS database by path, name and schema


USE ReportServer
        
        SELECT    
            RPT.Path ReportPath
            ,RPT.name ReportName
            ,SUBSTRING
                (
                    CONVERT
                        (
                            VARCHAR(MAX)
                            ,CONVERT
                                (
                                    XML
                                    ,CONVERT
                                        (
                                            VARBINARY(MAX)
                                            ,RPT.Content
                                        )
                                )
                        )
                    ,PATINDEX
                        (
                            '%xmlns="%'
                            ,CONVERT
                                (
                                    VARCHAR(MAX)
                                    ,CONVERT
                                        (
                                            XML
                                            ,CONVERT
                                                (
                                                    VARBINARY(MAX)
                                                    ,RPT.Content
                                                )
                                            )
                                        )
                                )+7
                    ,PATINDEX
                        (
                            '%">%'
                            ,CONVERT(VARCHAR(MAX)
                            ,CONVERT
                                (
                                    XML
                                    ,CONVERT
                                        (
                                            VARBINARY(MAX) 
                                            ,RPT.Content
                                        )
                                )
                        )
                ) 
            - PATINDEX
                (
                    '%xmlns="%'
                    ,CONVERT
                        (
                            VARCHAR(MAX)
                            ,CONVERT
                            (
                                XML
                                ,CONVERT
                                    (
                                        VARBINARY(MAX)
                                        ,RPT.Content
                                    )
                            )
                    )
                )
            -7
            ) ReportSchema 
        FROM ReportServer.dbo.[Catalog] RPT 
        WHERE RPT.Type = 2

USE ReportServer

SELECT

RPT.Path ReportPath

,RPT.name ReportName

,SUBSTRING

(

CONVERT

(

VARCHAR(MAX)

,CONVERT

(

XML

,CONVERT

(

VARBINARY(MAX)

,RPT.Content

)

,PATINDEX

(

'%xmlns="%'

,CONVERT

(

VARCHAR(MAX)

,CONVERT

(

XML

,CONVERT

(

VARBINARY(MAX)

,RPT.Content

)

)+7

,PATINDEX

(

'%">%'

,CONVERT(VARCHAR(MAX)

,CONVERT

(

XML

,CONVERT

(

VARBINARY(MAX)

,RPT.Content

)

- PATINDEX

(

'%xmlns="%'

,CONVERT

(

VARCHAR(MAX)

,CONVERT

(

XML

,CONVERT

(

VARBINARY(MAX)

,RPT.Content

)

-7

) ReportSchema

FROM ReportServer.dbo.[Catalog] RPT

WHERE RPT.Type = 2

Collapse

VB6: Using CBT Hooking to Change the Layout of the Native MsgBox Function

The Computer-Based Training, or CBT, API calls give the ability to automate screen functions in response to user actions, and in so doing create the ability for automated training modules to interact with students. Leveraging these functions allows a low-level event-based model, whereby a developer can use a hook to customize handling of screen-related activities.

This code allows font changes and various other format customizations of the standard VB6 MsgBox dialog box.

Expand

The Computer-Based Training, or CBT, API calls give the ability to automate screen functions in response to user actions, and in so doing create the ability for automated training modules to interact with students. Leveraging these functions allows a low-level event-based model, whereby a developer can use a hook to customize handling of screen-related activities.

This code allows font changes and various other format customizations of the standard VB6 MsgBox dialog box. It uses a CBT hook to intercept an internal window call, in this case, the window call generated by the MsgBox function. Upon intercepting the call it gets a handle to the MsgBox window as well as its various child windows (the label containing the message text, any buttons, and an icon if it exists). It then resizes the window to accommodate altered sizing, and repositions the icon and any command buttons. Finally, it positions the resized MsgBox window in the center of the screen.


'General Note: notes are above the line of code to which they apply.

Option Explicit

'Window size and position constants
Private Const ICON_WIDTH As Integer = 32
Private Const BTN_WIDTH As Integer = 75
Private Const BTN_HEIGHT As Integer = 23
Private Const BTN_SPACER As Integer = 6   'Space between 2 buttons
Private Const STW_OFFSET As Integer = 12  'Standard window offset: minimum window offset from the edge of 
                                          'its container

'SendMessage constants that we will use
Private Const WM_SETFONT = &H30
Private Const WM_GETTEXT = &HD

'Constants required for CBT hooking
Private Const HCBT_CREATEWND = 3
Private Const HCBT_ACTIVATE = 5
Private Const WH_CBT = 5

'Working variables that require module-wide scope
Private hHook As Long
Private myFont As IFont
Private cPrompt As String
Private hwndStatic As Long
Private ButtonHandles() As Long
Private xPixels As Long
Private yPixels As Long
Private isIcon As Boolean

'The API Type declarations we need
Private Type SIZE
    cx As Long
    cy As Long
End Type

Private Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type

Private Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" _
    (ByVal idHook As Long, ByVal lpfn As Long, ByVal hmod As Long, ByVal dwThreadId As Long) As Long

Private Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hHook As Long) As Long

'GETTEXT needs a String argument for lParam and SETFONT needs an Any argument there, so we "overload" 
'SendMessageA by providing two declarations
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
    (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function SendMessageS Lib "user32" Alias "SendMessageA" _
    (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As String) As Long

Private Declare Function SetWindowPos Lib "user32" _
    (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, _
    ByVal wFlags As Long) As Long

Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _
    (ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long

Private Declare Function EnumChildWindows Lib "user32" _
    (ByVal hWndParent As Long, ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long

Private Declare Function GetClientRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long

'Wrapper for the normal MsgBox function. The x and y arguments are optional and are in twips. If not 
'specified, myMsgBox will use default window sizes and positions. These work fine with default font sizes, 
'but usually don't with other sizes.

Public Function myMsgBox(Prompt As String, Buttons As VbMsgBoxStyle, ByVal fSize As Integer, _
    ByVal fBold As Boolean, ByVal fItalic As Boolean, ByVal fULine As Boolean, fFaceName As String, _
    Optional Title As String, Optional HelpFile As String, Optional Context As Long, Optional x As Long, _
    Optional y As Long) As Long

    cPrompt = Prompt
    
    Set myFont = New StdFont
    With myFont  'We can make whatever adjustments we like here to the font
         .SIZE = fSize 
         .Bold = fBold
         .Italic = fItalic
         .Underline = fULine
         .Name = fFaceName
    End With
    
    'Convert x and y arguments to pixels from twips. (Twips are the same size no matter the screen 
    'resolution; pixels aren't.)
    If Not IsMissing(x) Then
        xPixels = Int(x / Screen.TwipsPerPixelX)
    End If
    If Not IsMissing(y) Then
        yPixels = Int(y / Screen.TwipsPerPixelY)
    End If
    
    'Set up the hook to catch windows messages, call CBTProc when there is one
    hHook = SetWindowsHookEx(WH_CBT, AddressOf CBTProc, App.hInstance, 0)
    
    'This will call CBTProc, passing the handle of the MsgBox window to the wParam argument.
    myMsgBox = MsgBox(Prompt, Buttons, Title, HelpFile, Context)

End Function

Private Function CBTProc(ByVal lMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

    Dim i As Integer
    Dim statX As Integer   'X dimension of static (text) window
    Dim statY As Integer   'Y dimension of same
    Dim cLeft As Integer   'Current Left value for current button, used to position buttons along x axis
    Dim rc As RECT         'Used with GetClientRect

    If lMsg = HCBT_ACTIVATE Then

        'Immediately unhook (we have the handle we're looking for, and don't want to fire any more CBT 
        'events)
        UnhookWindowsHookEx hHook

        'Call EnumChildWindowProc once for each window that is contained in the MsgBox
        EnumChildWindows wParam, AddressOf EnumChildWindowProc, 0

        'Reinitialize the static buttoncount variable, see the proc
        EnumChildWindowProc 0, 1

        'Should always be true, but this prevents an abend if for some reason we fail to get the text
        'window.
        If hwndStatic Then

            'If the x parameter has been supplied to the main wrapper, then xPixels <> 0
            If xPixels <> 0 Then

                'Center the MsgBox window in the screen
                With Screen
                    SetWindowPos wParam, 0, (.Width / .TwipsPerPixelX - xPixels) / 2, _
                                (.Height / .TwipsPerPixelY - yPixels) / 2, xPixels, yPixels, 0
                End With

                'Analogous to the ScaleWidth and ScaleHeight properties. Client rectangle's dimensions 
                'are returned to the rc type and exclude the dimensions of the title bar and the borders.
                GetClientRect wParam, rc

                'Calculate x and y values for text window. If there's an icon, we need to reduce the size 
                'of the text window by the width of the icon plus a standard offset value.
                statX = rc.Right - rc.Left - STW_OFFSET * 2 - ((isIcon And 1) * (ICON_WIDTH + STW_OFFSET))
                statY = rc.Bottom - rc.Top - BTN_HEIGHT - STW_OFFSET * 2

                'We need to position the text window along the x axis such that it's a standard offset from 
                'the left border ofthe msgbox, plus the width of the icon and another standard offset if 
                'the icon exists.
                SetWindowPos hwndStatic, 0, STW_OFFSET + (isIcon And 1) * (ICON_WIDTH + STW_OFFSET), _
                             STW_OFFSET, statX, statY, 0
                isIcon = 0

                'Loop through the button handles, calculating the left border position each time.
                For i = 0 To UBound(ButtonHandles)
                    'Current left border is half the container window's width, less the width of half the 
                    'total number of buttons, plus the offset of the current button in the array.
                    cLeft = Int(xPixels / 2 + BTN_WIDTH * (i - (UBound(ButtonHandles) + 1) / 2))

                    'Modify the above to add button spacer widths.
                    cLeft = cLeft + BTN_SPACER * (i - (UBound(ButtonHandles) - 1) + 
                                    (UBound(ButtonHandles) Mod 2) / 2)

                    'The Y value is 1 standard offset more than the height of the text window.
                    SetWindowPos ButtonHandles(i), 0, cLeft, statY + STW_OFFSET, BTN_WIDTH, BTN_HEIGHT, 0
                Next
            End If

            SendMessage hwndStatic, WM_SETFONT, myFont.hFont, True

        End If
    End If

    CBTProc = 0 'allow operation to continue

End Function

Private Function EnumChildWindowProc(ByVal hChild As Long, ByVal lParam As Long) As Long

    Static ButtonCount As Integer
    Dim sLen As Integer
    Dim wClass As String
    Dim wText As String
    Dim rc As RECT

    If lParam Then
        ButtonCount = 0     'See the direct call of this proc in CBTProc: resets the ButtonCount 
        Exit Function       'variable to 0
    End If
    wClass = String(64, 0)

    'look up the type of the current window
    sLen = GetClassName(hChild, wClass, 63)
    wClass = Left(wClass, sLen)

    'We have either one or two static windows: optionally the icon (the first window if it's there) and the
    'text window (analogous to a label control).
    If wClass = "Static" Then

        'Find out whether the current window's text value is the same as the text passed in to the cPrompt         
        'argument in the main wrapper function. If it is, it's the text window and we store the handle 
        'value in hwndStatic. If it isn't, then it's an icon and we set the isIcon flag.
        If Not hwndStatic Then
            wText = String(Len(cPrompt) + 1, 0)
            sLen = SendMessageS(hChild, WM_GETTEXT, 255, wText)
            wText = Left(wText, sLen)
            If wText = cPrompt Then
                hwndStatic = hChild
            Else
                isIcon = True
            End If
        End If

    ElseIf wClass = "Button" Then

        'Store the button's handle in the ButtonHandles array
        ReDim Preserve ButtonHandles(ButtonCount)
        ButtonHandles(ButtonCount) = hChild
        ButtonCount = ButtonCount + 1
    End If

    EnumChildWindowProc = 1  'Continue enumeration

End Function

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'General Note: notes are above the line of code to which they apply.

Option Explicit

'Window size and position constants

Private Const ICON_WIDTH As Integer = 32

Private Const BTN_WIDTH As Integer = 75

Private Const BTN_HEIGHT As Integer = 23

Private Const BTN_SPACER As Integer = 6 'Space between 2 buttons

Private Const STW_OFFSET As Integer = 12 'Standard window offset: minimum window offset from the edge of

'its container

'SendMessage constants that we will use

Private Const WM_SETFONT = &H30

Private Const WM_GETTEXT = &HD

'Constants required for CBT hooking

Private Const HCBT_CREATEWND = 3

Private Const HCBT_ACTIVATE = 5

Private Const WH_CBT = 5

'Working variables that require module-wide scope

Private hHook As Long

Private myFont As IFont

Private cPrompt As String

Private hwndStatic As Long

Private ButtonHandles() As Long

Private xPixels As Long

Private yPixels As Long

Private isIcon As Boolean

'The API Type declarations we need

Private Type SIZE

cx As Long

cy As Long

End Type

Private Type RECT

Left As Long

Top As Long

Right As Long

Bottom As Long

End Type

Private Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" _

(ByVal idHook As Long, ByVal lpfn As Long, ByVal hmod As Long, ByVal dwThreadId As Long) As Long

Private Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hHook As Long) As Long

'GETTEXT needs a String argument for lParam and SETFONT needs an Any argument there, so we "overload"

'SendMessageA by providing two declarations

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _

(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Private Declare Function SendMessageS Lib "user32" Alias "SendMessageA" _

(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As String) As Long

Private Declare Function SetWindowPos Lib "user32" _

(ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, _

ByVal wFlags As Long) As Long

Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _

(ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long

Private Declare Function EnumChildWindows Lib "user32" _

(ByVal hWndParent As Long, ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long

Private Declare Function GetClientRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long

'Wrapper for the normal MsgBox function. The x and y arguments are optional and are in twips. If not

'specified, myMsgBox will use default window sizes and positions. These work fine with default font sizes,

'but usually don't with other sizes.

Public Function myMsgBox(Prompt As String, Buttons As VbMsgBoxStyle, ByVal fSize As Integer, _

ByVal fBold As Boolean, ByVal fItalic As Boolean, ByVal fULine As Boolean, fFaceName As String, _

Optional Title As String, Optional HelpFile As String, Optional Context As Long, Optional x As Long, _

Optional y As Long) As Long

cPrompt = Prompt

Set myFont = New StdFont

With myFont 'We can make whatever adjustments we like here to the font

.SIZE = fSize

.Bold = fBold

.Italic = fItalic

.Underline = fULine

.Name = fFaceName

End With

'Convert x and y arguments to pixels from twips. (Twips are the same size no matter the screen

'resolution; pixels aren't.)

If Not IsMissing(x) Then

xPixels = Int(x / Screen.TwipsPerPixelX)

End If

If Not IsMissing(y) Then

yPixels = Int(y / Screen.TwipsPerPixelY)

End If

'Set up the hook to catch windows messages, call CBTProc when there is one

hHook = SetWindowsHookEx(WH_CBT, AddressOf CBTProc, App.hInstance, 0)

'This will call CBTProc, passing the handle of the MsgBox window to the wParam argument.

myMsgBox = MsgBox(Prompt, Buttons, Title, HelpFile, Context)

End Function

Private Function CBTProc(ByVal lMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Dim i As Integer

Dim statX As Integer 'X dimension of static (text) window

Dim statY As Integer 'Y dimension of same

Dim cLeft As Integer 'Current Left value for current button, used to position buttons along x axis

Dim rc As RECT 'Used with GetClientRect

If lMsg = HCBT_ACTIVATE Then

'Immediately unhook (we have the handle we're looking for, and don't want to fire any more CBT

'events)

UnhookWindowsHookEx hHook

'Call EnumChildWindowProc once for each window that is contained in the MsgBox

EnumChildWindows wParam, AddressOf EnumChildWindowProc, 0

'Reinitialize the static buttoncount variable, see the proc

EnumChildWindowProc 0, 1

'Should always be true, but this prevents an abend if for some reason we fail to get the text

'window.

If hwndStatic Then

'If the x parameter has been supplied to the main wrapper, then xPixels <> 0

If xPixels <> 0 Then

'Center the MsgBox window in the screen

With Screen

SetWindowPos wParam, 0, (.Width / .TwipsPerPixelX - xPixels) / 2, _

(.Height / .TwipsPerPixelY - yPixels) / 2, xPixels, yPixels, 0

End With

'Analogous to the ScaleWidth and ScaleHeight properties. Client rectangle's dimensions

'are returned to the rc type and exclude the dimensions of the title bar and the borders.

GetClientRect wParam, rc

'Calculate x and y values for text window. If there's an icon, we need to reduce the size

'of the text window by the width of the icon plus a standard offset value.

statX = rc.Right - rc.Left - STW_OFFSET * 2 - ((isIcon And 1) * (ICON_WIDTH + STW_OFFSET))

statY = rc.Bottom - rc.Top - BTN_HEIGHT - STW_OFFSET * 2

'We need to position the text window along the x axis such that it's a standard offset from

'the left border ofthe msgbox, plus the width of the icon and another standard offset if

'the icon exists.

SetWindowPos hwndStatic, 0, STW_OFFSET + (isIcon And 1) * (ICON_WIDTH + STW_OFFSET), _

STW_OFFSET, statX, statY, 0

isIcon = 0

'Loop through the button handles, calculating the left border position each time.

For i = 0 To UBound(ButtonHandles)

'Current left border is half the container window's width, less the width of half the

'total number of buttons, plus the offset of the current button in the array.

cLeft = Int(xPixels / 2 + BTN_WIDTH * (i - (UBound(ButtonHandles) + 1) / 2))

'Modify the above to add button spacer widths.

cLeft = cLeft + BTN_SPACER * (i - (UBound(ButtonHandles) - 1) +

(UBound(ButtonHandles) Mod 2) / 2)

'The Y value is 1 standard offset more than the height of the text window.

SetWindowPos ButtonHandles(i), 0, cLeft, statY + STW_OFFSET, BTN_WIDTH, BTN_HEIGHT, 0

End If

SendMessage hwndStatic, WM_SETFONT, myFont.hFont, True

End If

CBTProc = 0 'allow operation to continue

End Function

Private Function EnumChildWindowProc(ByVal hChild As Long, ByVal lParam As Long) As Long

Static ButtonCount As Integer

Dim sLen As Integer

Dim wClass As String

Dim wText As String

Dim rc As RECT

If lParam Then

ButtonCount = 0 'See the direct call of this proc in CBTProc: resets the ButtonCount

Exit Function 'variable to 0

End If

wClass = String(64, 0)

'look up the type of the current window

sLen = GetClassName(hChild, wClass, 63)

wClass = Left(wClass, sLen)

'We have either one or two static windows: optionally the icon (the first window if it's there) and the

'text window (analogous to a label control).

If wClass = "Static" Then

'Find out whether the current window's text value is the same as the text passed in to the cPrompt

'argument in the main wrapper function. If it is, it's the text window and we store the handle

'value in hwndStatic. If it isn't, then it's an icon and we set the isIcon flag.

If Not hwndStatic Then

wText = String(Len(cPrompt) + 1, 0)

sLen = SendMessageS(hChild, WM_GETTEXT, 255, wText)

wText = Left(wText, sLen)

If wText = cPrompt Then

hwndStatic = hChild

Else

isIcon = True

End If

ElseIf wClass = "Button" Then

'Store the button's handle in the ButtonHandles array

ReDim Preserve ButtonHandles(ButtonCount)

ButtonHandles(ButtonCount) = hChild

ButtonCount = ButtonCount + 1

End If

EnumChildWindowProc = 1 'Continue enumeration

End Function

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VB6: Accessing the RichTextBox Control’s Underlying `iRichTextOLE` Interface

This code shows a way to work around the limitations of the VB6 RichTextBox control, accessing its underlying iRichTextOLE interface to implement support for later versions of the Text Object Model (TOM) than the one directly supported by the control.

Expand

This code shows a way to work around the limitations of the VB6 RichText control, accessing its underlying iRichTextOLE interface to implement support for later versions of the Text Object Model (TOM) than the one directly supported by the control.

The reason that the RichTextBox control doesn’t support much of the Rich Text specification is that it only directly supports RTF version 1.0, in part due to backward compatibility concerns. However, with a little sleight of hand, it is possible to get the RichTextBox control to use the latest RTF version (currently 4.1), thereby greatly expanding the usable feature set. You can do this by accessing the TOM interface directly.

First, along with the RichTextBox reference, we’ll need to add a reference to TOM (if not listed as an available reference — it usually isn’t — browse to riched20.dll and select it). Of course, we’ll also need a Form with a RichTextBox control on it (in this example, named rtcMyControl).


Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
    (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Const WM_USER = &H400&
Private Const EM_GETOLEINTERFACE = (WM_USER + 60) 

'This reference can point to any COM object, since by definition all COM objects inherit from IUnknown.
Dim myIUnknown As IUnknown   

'The ITextDocument object is the top-level object in the TOM.
Dim tomDoc As ITextDocument  
 
Sub Form_Load()

    'Use SendMessage to get a reference to the RichTextBox control's OLE interface (iRichEditOle). The 
    'iRichEditOle interface exposes the underlying COM interface (which is an implementation of RTF v4.1) 
    'of a RichTextBox control.
    SendMessage(rtcMyControl.hwnd, EM_GETOLEINTERFACE, 0&, myIUnknown)

    'Assign the reference to the iUnknown object. This causes a call to iUnknown's QueryInterface method, 
    'which will return ITextDocument as one of the interfaces it supports and therefore allow the reference 
    'to be added, exposing the functionality of the ITextDocument interface through the tomDoc variable. 
    tomDoc = myIUnknown

End Sub

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _

(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Private Const WM_USER = &H400&

Private Const EM_GETOLEINTERFACE = (WM_USER + 60)

'This reference can point to any COM object, since by definition all COM objects inherit from IUnknown.

Dim myIUnknown As IUnknown

'The ITextDocument object is the top-level object in the TOM.

Dim tomDoc As ITextDocument

Sub Form_Load()

'Use SendMessage to get a reference to the RichTextBox control's OLE interface (iRichEditOle). The

'iRichEditOle interface exposes the underlying COM interface (which is an implementation of RTF v4.1)

'of a RichTextBox control.

SendMessage(rtcMyControl.hwnd, EM_GETOLEINTERFACE, 0&, myIUnknown)

'Assign the reference to the iUnknown object. This causes a call to iUnknown's QueryInterface method,

'which will return ITextDocument as one of the interfaces it supports and therefore allow the reference

'to be added, exposing the functionality of the ITextDocument interface through the tomDoc variable.

tomDoc = myIUnknown

End Sub

All this is necessary because the line Dim tomDoc as iRichEditOle fails to compile, even though iRichEditOle is a COM interface. The reason that it fails to compile is that iRichEditOLe doesn’t implement a dual interface, that is, it implements iUnknown as all COM classes do, but does not implement iDispatch.

VB’s direct support of COM is limited to those COM classes that implement both interfaces. VB directly supports only those interfaces that allow late binding, and late binding requires implementation of iDispatch. Nevertheless, as this example shows, VB can access any COM object through the use of API techniques similar to this one.

Collapse

Blackjack Diagrams

This is a collection of diagrams that model different aspects of the Ruby Blackjack game.

Expand

This collection of diagrams models different aspects of the Blackjack game. There is a class diagram and three flowcharts: an overall flow model, a calculate hand subprocess and a calculate 21 subprocess.

Class Diagram

Main Flowchart

Subroutine: Calculate Hand Total

Subroutine: Check for Natural 21

Collapse

Mixing BSCS: Preprocessing Logic

The Mixing Business Support Control System controls a rubber mixing machine that is part of an overall process of manufacturing tires. This diagram shows the preprocessing logic, which verifies that an authorized employee has selected one of two correct ingredient specifications for the mixing machine.

Expand

The Mixing Business Support Control System controls a rubber mixing machine that is part of an overall process of manufacturing tires. This diagram shows the preprocessing logic, which verifies that an authorized employee has selected one of two correct ingredient specifications for the mixing machine.

Collapse

Mixing BSCS: Process Barcode Scan

The Mixing Business Support Control System controls a rubber mixing machine that is part of an overall process of manufacturing tires. This diagram shows all the checks that are made to a bale of rubber in the input queue before allowing it to be introduced into the mixer.

Expand

The Mixing Business Support Control System controls a rubber mixing machine that is part of an overall process of manufacturing tires. This diagram shows all the checks that are made to a bale of rubber in the input queue before allowing it to be introduced into the mixer.

Collapse

PD Manager: Wireframe Sketch of Field Contact Entry Form

This is a wireframe sketch of a field contact report entry. A field contact is an interaction between a police officer and a citizen while on patrol, either because the circumstances appear suspicious, or because the officer is looking for information about a specifically identified situation.

Expand

This is a wireframe sketch of a field contact report entry. A field contact is an interaction between a police officer and a citizen while on patrol, either because the circumstances appear suspicious, or because the officer is looking for information about a specifically identified situation.

Collapse

PPLS: Process Vendor RFQs

This diagram shows the flow of work for generating Vendor RFQs (Requests for Quote) for multiple open DIBBS (Defense Logistics Agency Internet Bulletin Board System) solicitations for a single NSN (National Stock Number). A Base RFQ joins a group of solicitations for one NSN to a group of vendor RFQs for parts conforming to that NSN; this diagram shows the process from the context of a single base RFQ/single NSN.

Expand

This diagram shows the flow of work for generating Vendor RFQs (Requests for Quote) for multiple open DIBBS (Defense Logistics Agency Internet Bulletin Board System) solicitations for a single NSN (National Stock Number). A Base RFQ joins a group of solicitations for one NSN to a group of vendor RFQs for parts conforming to that NSN; this diagram shows the process from the context of a single base RFQ/single NSN.

Collapse

HealthCompare.com: Click-Through Commission Technical Design

This is a technical design document for an enhancement to an online enrollment system application. The enhancement enables the awarding of click-through commissions to linked websites.

Expand

This is a technical design document for an enhancement to an online enrollment system application. The enhancement enables the awarding of click-through commissions to linked websites.

Collapse

UML: Documenting System Architecture and Behavior

This document contains a sampling of diagrams and other artifacts that document a software system. Taken together, the items illustrate an approach to documenting a problem domain, from a high-level overview down to details of architecture and behavior.

Expand

This document contains a sampling of diagrams and other artifacts that document a software system. Taken together, the items illustrate an approach to documenting a problem domain, from a high-level overview down to details of architecture and behavior.

Collapse

AP Style Guide

A guide for writers and editors working with AP style to use as a reference.

Expand

A guide for writers and editors working with AP style to use as a reference.

AP Style and Punctuation Guide

Abbreviations

Using periods in abbreviations
1. Do not use periods in abbreviations of three or more words: NCAA, USC, UCLA.
  1. If the abbreviation would otherwise spell a word, then use periods: c.o.d..
2. In general, use periods in abbreviations of two words: U.S., U.K., U.N. However, there are numerous exceptions such as AP, IT and GI. (When in doubt, use periods. If you see something all the time without periods, don’t use them.)
  1. A sportswriting exception: do not use periods in two-word abbreviations of universities: OU, ND.
Dates
1. Do not abbreviate days of the week.
2. When a month is on its own or with just a year, don’t abbreviate it: My birthday is in September. I was born in September 1976.
3. When a month is used with a specific day, abbreviate those with more than five letters (all months except March through July). Use the first three letters of the month to abbreviate: My birthday is on Sep. 15.
Symbols
1. Always spell out cents and percent (don’t use ¢ or %). Always use numerals (don’t write out the number) with cents and percent: 5 cents, 1 percent, 25 cents, 100 percent.
2. Use $ if it accompanies a number: $5 (not $5.00),$49.95, $1 million.
3. Use & (ampersand) only if it is part of an organization name: Texas A&M.
  1. In particular, avoid using & in titles for technical reasons: Google can interpret it as code. If you find that you have to use an ampersand in a title, such as with Texas A&M, take care that there is no space before or after it.
4. Abbreviate “number” as No., and do not write out any numbers you use: No. 1, No. 84. (In case you were ever curious, this abbreviation comes from the French word for number, which is numéro.)
Personal Titles
1. For coaches, always use Coach as a title, if you use any title at all. Do not use HC, OC or DC. Those are job descriptions rather than titles, analogous to player positions such as QB and LB.
2. Certain personal titles are abbreviated when given along with a person’s name: Dr. Marcus Welby, Gen. Robert E. Rodes. Certain are not: President Abraham Lincoln, Vice President Andrew Johnson. (For an exhaustive list of what titles to abbreviate and when, see http://writingexplained.org/ap-style/ap-style-titles, in particular the several links in the Additional Guidance section at the bottom.)
Player and Coaching Positions
1. Do not use HC, OC or DC as abbreviations for head coach, offensive coordinator and defensive coordinator, unless you are writing a coach’s opinion or analysis article and referring to the job description frequently. (In such a case, you may abbreviate any but the first use in your article.) Keep in mind that these are job descriptions rather than titles, and therefore are not to be capitalized when not abbreviated.
2. Do not capitalize player positions such as quarterback.

1. It is acceptable to use the standard one- or two-letter abbreviations for player positions, if you are using them frequently in an article. Write out the position on first use.
Football plays
1. When discussing a play in an analysis article, write it out the first time, then use common abbreviations in subsequent references if you prefer. Capitalize the abbreviations: RPO, QBS.
Streets and Street Addresses
1. If there is no street address, spell out the street name and direction (North, West, etc.): The city will close West Main Street.
  1. An exception is when the street name is a number. In this case, apply the rules for writing numbers: East 75^th Street, Fifth Avenue.
2. If using the entire street address, abbreviate everything you can, using periods in all cases: 5 W. 75^th St., 846 Park Ave.
  1. However, do not abbreviate Circle, Court, Drive or Road.

U.S. States

Do not abbreviate states when they appear alone: The Ducks left for southern California yesterday.
Do not abbreviate states with five or fewer letters: Idaho, Iowa, Maine, Ohio, Texas and Utah.
Do not abbreviate Alaska or Hawaii.
Abbreviate all other states when they appear in conjunction with the name of a city, town, village or military base: Eugene, Ore.., Fort Sill, Okla.

When abbreviating, do not use the ZIP code two-letter abbreviations. Use the standard state abbreviations:

Ala.	Ariz.	Ark.	Calif.	Colo.	Conn.
Del.	Fla.	Ga.	Ill.	Ind.	Kan.
Ky.	La.	Mass.	Md.	Mich.	Minn.
Miss.	Mo.	Mont.	N.C.	N.D..	N.H.
N.J.	N.M.	N.Y.	Neb.	Nev.	Okla.
Ore.	Pa.	R.I.	S.C.	S.D..	Tenn.
Vt.	Va.	W.Va.	Wash.	Wis.	Wyo.

Ala.	Ariz.	Ark.	Calif.
Colo.	Conn.	Del.	Fla.
Ga.	Ill.	Ind.	Kan.
Ky.	La.	Mass.	Md.
Mich.	Minn.	Miss.	Mo.
Mont.	N.C.	N.D..	N.H.
N.J.	N.M.	N.Y.	Neb.
Nev.	Okla.	Ore.	Pa.
R.I.	S.C.	S.D..	Tenn.
Vt.	Va.	W.Va.	Wash.
Wis.	Wyo.

U.S. Cities
1. Do not abbreviate any part of U.S. city names, even if they contain words that are often abbreviated in street names: South Bend, Ind.; North Platte, Neb..
2. The lone exception to this is always to abbreviate the word Saint: St. Louis, St. Paul, Minn..

Include the state with the city, except with these major cities:

Atlanta	Baltimore	Boston	Chicago	Cincinnati
Cleveland	Dallas	Denver	Detroit	Honolulu
Houston	Indianapolis	Las Vegas	Los Angeles	Miami
Milwaukee	Minneapolis	New Orleans	New York	Oklahoma City
Philadelphia	Phoenix	Pittsburgh	St. Louis	San Diego
San Francisco	Seattle	Salt Lake City	San Antonio	Washington

Atlanta	Cleveland	Houston
Milwaukee	Philadelphia	San Antonio
Baltimore	Dallas	Indianapolis
Minneapolis	Phoenix	San Diego
Boston	Denver	Las Vegas
New Orleans	Pittsburgh	San Francisco
Chicago	Detroit	Los Angeles
New York	St. Louis	Seattle
Cincinnati	Honolulu	Miami
Oklahoma City	Salt Lake City	Washington

Atlanta	Cleveland
Houston	Milwaukee
Philadelphia	San Antonio
Baltimore	Dallas
Indianapolis	Minneapolis
Phoenix	San Diego
Boston	Denver
Las Vegas	New Orleans
Pittsburgh	San Francisco
Chicago	Detroit
Los Angeles	New York
St. Louis	Seattle
Cincinnati	Honolulu
Miami	Oklahoma City
Salt Lake City	Washington

Capitalization

Always capitalize the first word of a sentence. This rule overrides all other capitalization rules.
Capitalize proper nouns (names of specific persons, places or things): Notre Dame Fighting Irish, Marcus Freeman, Sacred Heart Basilica.
There are a few exceptions, usually brand names such as eBay. (Avoid putting those exceptions at the beginning of a sentence, as you will have to capitalize them.)
If a common noun is part of a name, do not capitalize it if it’s in plural form (when referring to more than one of the same type of thing): the Ohio and Mississippi rivers, lakes Erie and Ontario, Autzen and Reser stadiums. An exception to this is if a common noun is part of a nickname for a sports team: The Chicago Bears, The Oregon Ducks. In this case, capitalize the word even when using only the nickname: The Bears, The Ducks.
For more capitalization rules for names of persons, see Names of Persons below.
Sports Coaches, Players and Teams
1. Do not capitalize head coach, offensive coordinator, defensive coordinator, etc. and do not use them as titles. Use Coach (capitalized) for the title of any coach: Coach Marcus Freeman rather than Head Coach Marcus Freeman. Head coach is a job description rather than a title: Notre Dame’s new head coach, Marcus Freeman, arrived in South Bend yesterday.
2. Do not capitalize player positions such as quarterback.
3. If you are using an abbreviation for a player or coach, capitalize it: HC, OC, DC, QB, LB, WR, etc.
4. Do not capitalize a player’s academic year: senior quarterback Patrick Mahomes.
5. Do not capitalize terms such as defensive line, red zone or offensive line.
6. Do not capitalize names of plays: dive play, off tackle, run-pass option, quarterback sneak.
7. For more information on AP style as specifically applied to football, see http://www.ap.org/press-releases/2012/ap-compiles-super-bowl-style-guide.
Compass points
1. Capitalize regions that use a compass point: The Southeast is a major recruiting area.
2. Capitalize names of areas that are equivalent to proper names: London’s East End neighborhood.
3. Do not capitalize directions that use a compass point: Tornadoes generally move northeast.
Capitalize words that derive from a proper noun when the noun is part of the meaning: Shakespearean, Socratic. Do not capitalize words deriving from a proper noun if they no longer depend on the noun for their meaning: english (when referring to spin on a ball in billiards and pool), french fries, herculean.

Capitalize awards and decorations: the Heisman Trophy, the National Championship Trophy, the Dick Butkus Award.
Capitalize family words when they are used as a substitute for a person’s name: Mom and Dad came to visit the campus. Otherwise, do not capitalize them: My mother and father came to visit the campus.
Capitalize names of specific animals: Bevo the steer, Uga the bulldog. Capitalize proper nouns in animal breeds: Uga is an English bulldog, Bevo is a Texas longhorn steer.
1. However, Bevo is the Texas Longhorns’ steer is correct. Texas Longhorns is a proper name, therefore Longhorns is capitalized.
Do not capitalize plant names unless they contain a proper noun: white pine, Sitka spruce, Douglas fir.
Do not capitalize seasons unless they are part of a proper name: spring ball, the Oregon Spring Game.

Dates and Times

Dates
1. Use numbers for days: Jan. 1 rather than Jan. 1^st.
2. Write out days of the week in full.
3. Capitalize months.
4. When a month is on its own or with just a year, don’t abbreviate it: My birthday is in September. I was born in September 1976.
5. When a phrase lists only a month and year, do not separate the month and the year with commas: February 1980 was his best month.
6. When a month is used with a specific day, abbreviate those with more than five letters (all months except March through July). Use the first three letters of the month to abbreviate: My birthday is on Sep. 15.
7. When a date has a month, day and year, set off the year with commas: Sep. 4, 2024, is a day we are all waiting for.
Times
1. Use numerals for all times, along with a.m. or p.m.: Our meeting was at 2:30 p.m. Do not use zeros with times that are on the hour: 2 p.m. rather than 2:00 p.m.
2. Exceptions:
  1. Do not use 12 a.m. or 12 p.m., as these are inaccurate (a.m. and p.m. are abbreviations for the Latin ante meridiem and post meridiem, meaning before midday and after midday, respectively). Use noon and midnight (without using 12) instead. If you need to abbreviate them (for example, you have a table of hourly times), you may use 12 n. and 12 m.
  2. When using the word o’clock, standard rules for numbers apply: four o’clock, 10 o’clock.
3. If the time includes minutes, separate the hour and minutes with a colon: 12:45 p.m.
4. If the time includes seconds, separate them from the minutes with a colon as well: The current world record in the men’s marathon is 2:02:57. Neil Armstrong took his first step on the moon on July 21, 1969, at 10:56:12 p.m. EDT.

Italics

Italicize the titles of complete works. The titles of comparatively short works — songs, short poems, essays, and episodes of TV programs — should be enclosed in quotation marks instead.

Some examples:

1. Books: Catch-22, by Joseph Heller
2. Magazines and journals: Time
3. Newspapers: The Times
4. Plays: A Raisin in the Sun, by Lorraine Hansberry
5. Movies: The Godfather
6. Television programs: Doctor Who
7. Works of art: Nighthawks, by Edward Hopper
8. Albums and CDs: OK Computer, by Radiohead
Italicize the names of aircraft, ships and trains, foreign words used in an English sentence, and words and letters discussed as words and letters. For example:
1. “These are the voyages of the starship Enterprise.” (Title sequence of the original Star Trek TV series)
2. From 1925 to 1953, a passenger train named the Orange Blossom Special brought vacationers to sunny Florida from New York.
3. “There is no danger that Titanic will sink. The boat is unsinkable and nothing but inconvenience will be suffered by the passengers.” (Phillip Franklin, Vice President of White Star Line)
4. “Come kiss me, and say goodbye like a man. No, not good-bye, au revoir.” (William Graham, “Chats With Jane Clermont,” 1893)
5. “Every word she writes is a lie, including and and the.” (Mary McCarthy on Lillian Hellman)
Use italics to emphasize words and phrases:
1. “I don’t even like old cars. I mean they don’t even interest me. I’d rather have a … horse. A horse is at least human, for God’s sake.” (J. D. Salinger, The Catcher in the Rye)
2. However, it is wise to keep this in mind: “Think of italics as butterflies that might swoop across the page, allow them to flit about, land here and there, softly; gently; don’t treat them as a blanket that must spread itself across the entire page. The butterfly approach will bring a dash of color; the blanket approach will darken everything.” (William Noble, Noble’s Book of Writing Blunders (and How to Avoid Them), Writer’s Digest Books, 2006)

Names of Persons

The first time you refer to a person in an article, use the person’s full name, as well as any appropriate title. Thereafter, use only the person’s last name.

In particular, do not refer to a coach as Coach in any references but the first one (where it is optional), unless the reference is part of a quote. Again, just use the last name in references subsequent to the first one.
However, you may use the first name (and any appropriate title) again as part of a summary paragraph at the end of the article.

Do not use Mr., Mrs., Ms. or Miss with names, unless they are part of a quote.
Do not precede Sr. or Jr. with a comma: Mike Sanford Sr., Mike Sanford Jr.
It’s important to distinguish between a personal title and a job description. These are titles: Gen. Robert E. Rodes, Dr. Marcus Welby. If you are using the title as part of a job description, don’t abbreviate or capitalize it: Confederate general Robert E. Rodes, television doctor Marcus Welby.

Numbers

The cardinal numbers (one, two, three, etc.) zero through nine are written out, as are the ordinal numbers (first, second, third, etc.) first through ninth. and above are written as numerals: 10, 11, 12; 10^th, 11^th, 12^th.

Some exceptions to these rules are:

Write out a number when it begins a sentence: Twenty-four years ago, I bought my house. Two exceptions to this exception:

When citing a year at the beginning of a sentence, use the numeral: 2016 is the first year that Washington has beaten Oregon since 2003.
When citing a score at the beginning of a sentence, use the numeral: 24-22 was a much closer score than expected.

When citing a score involving a number less than 10, use the numeral: Oregon beat Old Dominion by a score of 58-3. (Spell out a number less than 10 if you don’t use a hyphen: a score of 58 to three.)
Always write an age as a number, when you are using just the number: Frank had two boys: Joe, 5 and James, 3.(However, Joe was five years old is correct.)
1. If the age is less than one year, the normal rules for numbers apply: six months, 11 months.
Write out numbers in proper names: Final Four.
Use the numeral for all numbers except zero when writing a series of statistics: Freeman had 185 yards on 18 carries, 2 touchdowns and zero fumbles. (Of course, you could say no fumbles here if you prefer.)
Use the numeral in most sports-specific expressions involving numbers: 4-star recruit, 3^rd and 9, 4^th down, 5-yard line, 3-point shot, par 4, 3-1 odds. However, when using ordinal numbers in a compound adjective (which is hyphenated) it is acceptable to write them out. For example, feel free to use fourth-down yardage instead of 4^th-down yardage, if it looks better to you.
1. When referring to weeks of a season use the numeral: week 1 rather than week one.
Do not spell out monetary numbers, and do not add zeros for whole-dollar amounts: $6 rather than $6.00 or six dollars.

An exception: write out expressions such as a dollar, a couple of dollars, two or three dollars. (Make a dollar or two would look very funny if written make $1 or $2.)

Write out numbers contained in well-known expressions: a picture is worth a thousand words, if I had a million dollars, an eleventh-hour comeback, a high-five.

For a list of quite a few other exceptions, see http://writingexplained.org/ap-style/ap-style-numbers.

Punctuation

Exclamation Point
1. Be careful not to overuse exclamation points. Use them to indicate something surprising or something that stands out significantly from the surrounding context.
2. Do not double exclamation points or combine them with other punctuation such as question marks.
3. Use them only at the end of a complete sentence, unless they are part of a quotation (for more information on combining exclamation points and quotation marks, see the section on quotation marks).
4. If you are using an informal tone, you may use one in parentheses (!) to indicate surprise or amusement at something that you are saying.
Period
1. A period ends a sentence, or indicates an abbreviation.
2. For more information on how to combine periods and quotation marks, see the section on quotation marks.

Question Mark
1. Use a question mark only when the sentence asks a question.
  1. In particular, avoid using a question mark to indicate a “dramatic pause”: If you don’t submit your article on time? You will be beheaded.
2. Use a question mark only at the end of a complete sentence, unless it is part of a quotation (for more information on combining question marks and quotation marks, see the section on quotation marks).
Apostrophe

Apostrophes are the cause of many spelling errors. It’s important to have a thorough understanding of how to use (and how not to use) them.
1. Apostrophes are used in three situations:
  1. To indicate letters left out in a contraction: isn’t, you’re, we’d, etc.
  2. To indicate the possessive case with a common or proper noun, with s: Oregon’s team, the team’s players.
  3. To indicate the plural of a single letter, with s: mind your p’s and q’s, this sentence contains a total of six t’s.
2. When using an apostrophe with the possessive case, these rules apply:
  1. Singular noun: add ’s to the word: Oregon’s schedule, the team’s schedule.
  2. Plural noun ending in s: add just an apostrophe to the word: the Ducks’ schedule, the Pac-12 teams’ schedules, girls’ basketball.
  3. Irregular plural noun not ending in s: same rule as a singular noun: women’s basketball, children’s music.
3. The rules for singular nouns that end in s are a bit complicated. The Chicago Manual of Style suggests treating them the same as any other singular noun: the Jones’s car, the boss’s office. AP Style’s rules are more complicated, and not always adopted:
  1. If the noun is a proper noun, just add an apostrophe: the Jones’ car.
  2. If the noun is a common noun, add ’s: the boss’s office.
  3. In rare cases where the s isn’t pronounced in a common expression, omit it from the spelling: for goodness’ sake, but for completeness’s sake.
4. Apostrophes are often misused. Here are some typical mistakes to avoid:
  1. Do not use an apostrophe in plurals of proper nouns ending in s: keeping up with the Joneses, not keeping up with the Jones’s (or Jones’). This is easy to confuse because of the Jones’s house (i.e. the house belonging to the Joneses, a possessive).
  2. Do not use an apostrophe to indicate the plural of an abbreviation: RBIs, INTs, CDs rather than RBI’s, INT’s, CD’s.
  3. Do use an apostrophe to indicate a plural reference to a letter: mind your p’s and q’s, dot all the i’s and cross all the t’s.

Comma
1. When writing numerals, use a comma with a four-digit number: 1,025.
2. Exceptions are years: 2017, street addresses: 15650 Arthur St. and page numbers.
3. Set off degrees and certifications with a comma after a person’s name: John Jones, Ph.D. or Marcus Welby, M.D.
4. Set off direct addresses of persons or groups with commas: Thank you, Mr. and Mrs. Jones, for your kind donation. Just think, fellow Scouts, what we will be able to do with these funds. Friends, we will be looking for your ideas in next week’s meeting.
5. With dates, these rules apply:
  1. Separate day, date and year with commas: Saturday, Sep. 4, 2017.
  2. Omit the comma when only using month and year: September 2017. (Also, do not abbreviate the month in this case.)
6. Separate geographic references with commas: The University of Oregon is in Eugene, Lane County, Ore.
7. When listing a group of related items, list each one separated by a comma, except omit the comma after the second-to-last item: My siblings’ names are Anne, John, David, Peter, Paul and Mary.
  1. If the sentence is ambiguous without it, use the last comma: The meal consisted of steak, green beans, and macaroni and cheese.
8. Separate multiple adjectives that modify the same noun with a comma: It was a windy, blustery day.
  1. Do not separate adjectives that are not really multiple modifications to the noun: bright green jerseys are not the same thing as bright, green jerseys.
9. Set off non-essential information in a sentence with commas: Joe, who was in a hurry, left without his books. The main sentence is Joe left without his books. The fact that he was also in a hurry is additional information. Contrast this with The student who was in a hurry left without his books. In this sentence, there are other students who were not in a hurry and did not leave without their books, so who was in a hurry is essential to explaining who left without his books. (For more information, see the section on which vs. than in Common Errors and Points of Style.)
10. Use a comma to join two complete sentences with a coordinating conjunction (and, but, for, or, nor, so, yet): The Ducks had a rough season last year, so they hired a new coach.
  1. In short sentences, you may omit the comma: I brought the hamburgers and Joe grilled them.
  2. Do not use a comma if one of the sentences is incoimplete: Joe is looking for four tickets but will settle for two. (Compare Joe is looking for four tickets, but he will settle for two.)
11. If a dependent clause (a part of a sentence that can’t stand on its own, so it has to be part of another sentence) precedes an independent clause (a part of a sentence that is a complete sentence on its own), then separate it with a comma: If you don’t get in line soon, you won’t get a ticket. If the dependent clause follows the independent clause, do not use a comma: You won’t get a ticket if you don’t get in line soon. (Note that you won’t get a ticket is a complete sentence, and if you don’t get in line soon is not.)

Semicolon
1. A semicolon is used to join two complete and related sentences: Jim had 1,338 rushing yards last season; Joe, in three fewer games, had 1,268.
2. You can also use semicolons to join complex lists when necessary: You have these choices available: green, red or blue; square, circle or triangle; and small, medium or large.
Colon
1. Use a colon to introduce a quote or example: This is a quote or example.
2. Use a colon to introduce a list: Three coaching positions will report directly to the head coach: offensive coordinator, defensive coordinator and special teams coordinator.
3. Use a colon to introduce a clarifying word or phrase at the end of a sentence: One thing more than any other is the source of improvement: showing up for practice.
4. A colon should always follow an independent clause (a group of words that can stand on their own as a complete sentence).
5. If a colon introduces more than one complete sentence, capitalize the word just after the colon: Willie Taggart has three rules: Make no excuses. Blame no one. Do something. If there is only one complete sentence, don’t capitalize it: Willie Taggart has one rule: do something.
6. Colons are also used between the hours, minutes and seconds of a time: 3:35:07 p.m. None of the above rules apply in this situation.
Hyphen

The rules for the use of hyphens are fluid. They change fairly often, and there are many inconsistencies in the way that they are applied. For example, e-mail was common 20 years ago, and now it is almost entirely replaced with email. Online was on-line before the internet became ubiquitous. At the same time, many other less common “e” compounds still retain the hyphen, such as e-book and e-learning. For some common hyphenation errors, see Common Errors and Points of Style. For an exhaustive list of rules, see The Chicago Manual of Style’s 10-page online document on the subject. These rules also apply to AP Style.
Dash
1. Dashes give a sense of interrupting the flow of thought. Use a dash to set off part of a sentence more strongly that you would by using commas: Joe gained just 43 yards — a far cry from his usual total.
2. In AP style, dashes are always em dashes (—). They are always preceded and followed by a space, except when they begin or end a sentence. At the beginning of a sentence, omit the leading space; at the end of a sentence, omit the trailing space.
Ellipsis
1. An ellipsis is written as space, three periods, space, so: “ … ” with two exceptions. If the ellipsis begins the first sentence in a paragraph, omit the first space; if it ends the last sentence, omit the last space. (These exceptions don’t come up very often.)

1. Use an ellipsis to show parts of the middle of a quotation that you are leaving out. Suppose Joe says this: “We are fumbling too often. We have to be more careful to hold on to the ball. If we don’t, we’re going to have trouble winning games. Taking care of the ball wins games.” You can use an ellipsis to abbreviate this to Joe said “We have to be more careful to hold on to the ball … Taking care of the ball wins games.” Notice that you do not put an ellipsis at the beginning of the quote, even though you don’t start it at the beginning.
2. Use an ellipsis to suggest a trailing off of thought: Perhaps we could take … well, perhaps not.
Parentheses
1. Parentheses (the plural of parenthesis) are always used in pairs. Use parentheses to set off “as an aside” statements from the main flow of the sentence: Oregon has won the conference championship six times (although they have yet to win a national championship).
2. The closing parenthesis goes before the final punctuation (period, question mark or exclamation point) if it is part of a larger sentence (this is an example). If it is part of an entire sentence, the final punctuation goes inside the closing parenthesis. (This is an example.)
Quotation Marks
1. Periods and commas always go inside quotation marks: Joe said “I’ll be leaving now.” and “I’ll be leaving now,” Joe said.
2. All other punctuation goes outside quotation marks: Did Jim say “I know”?
3. The exception to this is if the punctuation is part of the quotation itself: “Who knows?” Jane asked. “Look out!” Joe cried.
Angle Brackets
1. Use angle brackets to add your own words to a quote, to make clarifications or comments to it. Suppose Joe says this: “We are fumbling too often. We have to be more careful to hold on to the ball. If we don’t, we’re going to have trouble winning games.” You could quote Joe this way: “We are fumbling too often … If we don’t [hold on to the ball], we’re going to have trouble winning games.”
2. Use [sic] to show the reader that you are quoting something as written, when there are errors in the writing. Do not correct the original quote: According to Dan Dropout of Second-Rate Sports, “Oregon has to do better with there [sic] defensive line.”

Titles of Articles

Most words in titles are capitalized.
Always capitalize the first and last words of a title.
Capitalize everything else except a, an, and, at, but, by, for, in, nor, of, on, or, out, so, the, to, up, and yet. Optional exceptions:
1. This one gets tricky, so feel free not to use it. So, up and yet can also be used as adverbs. When they are, you may capitalize them if you think it looks better. Examples:
  1. Ducks Gain Only 75 Yards Rushing yet Still Win
  2. Ducks Have Yet to Lose
  3. Jones Misses Practice so He Can Rest Injured Pinky
  4. Why There Are So Many Injuries in Football
  5. Jones Walks up the Stairs
  6. Jones Looks Up an Old Friend

1. The way to tell if the word is being used as an adverb is to see if it modifies a verb, an adjective or another adverb. In sentence ii above, the word yet modifies the verb have. In sentence iv, the word so modifies the adjective many. In sentence vi, the word up modifies the verb looks.
2. To also functions as an adverb in a few idiomatic expressions: come to (regain consciousness), fall to (start in on something, as in We fell to with a will), pull to (close, as in pull a door to). In these cases, you may also capitalize to.
3. Capitalize to in the expression to and fro if you think that The Ducks Ran to and Fro looks funny.
In particular, be careful to capitalize forms of the verb to be: am, are, is, was and were, and forms of the verb to do: do, does and did.
If you have a title and you’re unsure whether you’re capitalizing it correctly, https://capitalizemytitle.com/ is an excellent resource to check it.

AP Style Miscellanies

In 2010, the AP style changed from Web site to website.
In 2011, e-mail became email. However, other e-terms still retain the hyphen: e-book, e-commerce, e-business.
In 2014, AP style determined that more than and over could be used interchangeably, when referring to an amount: over 200 yards rushing, more than 200 yards rushing — Mike Shor’s tweet “More than my dead body!” notwithstanding.
In 2016, Internet became internet and Web became web.

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Common Writing Errors

This document addresses a number of common mistakes that people make when writing: its vs. it’s, affect vs. effect, and so on.

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This document addresses a number of common mistakes that people make when writing: its vs. it’s, affect vs. effect, and so on.

Common Writing Errors

This is a list of grammar, punctuation and spelling errors that are easy to get wrong in writing and/or editing.

Like vs. such as: use like for comparisons and such as for inclusions. There are no teams like the New York Yankees. Teams that spend a lot of money, such as the New York Yankees, are perennial World Series contenders.
A compound sentence joins two complete — often shorter — sentences into one, using a coordinating conjunction to join them. (There are seven coordinating conjunctions: and, but, or, for, nor, so and yet.) When writing a compound sentence, use a comma before the conjunction that joins the two sentences: I’m a fine writer, but I’m a controversial one as well. If you are not joining two complete sentences, omit the comma: I am a fine writer but a controversial one as well.
Know the difference between then and than. First this, then that. I would rather be first than second. Then deals with time sequences. Than deals with comparisons and choices.
Contractions and possessive nouns always have apostrophes, and possessive pronouns never do. If you remember this, you will not have trouble with your vs.you’re, their vs. they’re and especially its vs. it’s (its is probably the most often misspelled word in the English language).

These are the possessive pronouns:
1. hers
2. his
3. its
4. mine
5. ours
6. theirs
7. yours
Note that none of them have an apostrophe.
Which vs. that: Use which for non-restrictive clauses and that for restrictive clauses.

A clause is group of related words containing a verb. A complete sentence, then, always has at least one clause. It will often have more than one. The words in a clause are not necessarily contiguous in a sentence.

Here is a sentence with two clauses:

Chairs that don’t have cushions are uncomfortable.

The main clause (the complete sentence) is Chairs are uncomfortable. The additional clause in the first sentence is that don’t have cushions. We don’t want to say that all chairs are uncomfortable, so we add another clause to explain that only chairs without cushions are uncomfortable. In other words, we restrict the chairs we’re calling uncomfortable to those without cushions. So, that don’t have cushions is a restrictive clause.

Now, let’s change the sentence, replacing that with which:

Chairs, which don’t have cushions, are uncomfortable.

Now, we’re not only saying that all chairs are uncomfortable, we’re saying that none of them have cushions, either! We are not restricting the type of chairs we’re talking about. So, which don’t have cushions is a non-restrictive clause.

Notice also that which don’t have cushions is set off by commas, and that don’t have cushions is not. So, there is one more part to the rule: non-restrictive clauses are set off by commas, and restrictive clauses aren’t.

Now that you know the difference between a restrictive and a non-restrictive clause, here is the whole rule:

Use which with non-restrictive clauses, and set off the clause with commas. Use that with restrictive clauses, and do not set off the clause with commas.
When using a or an with an initialism, use whichever you would use with the first letter alone: an HTML, an LCD, a CICS, an RGB, a UPS.

Initialisms are often incorrectly called acronyms. If you pronounce the abbreviation as a word, it’s an acronym: ANSI, WYSIWYG, DOS, LAMP. If you don’t, it’s an initialism: API, PHP, SMTP.. This rule does not apply to acronyms.

This can get a bit confusing. For example, it’s an SMTP server, but a SOAP message. The fact that the S in SMTP stands for simple has nothing to do with whether you use a or an in front of it. What matters is what you would use in front of the first letter S by itself.
Avoid misplaced modifiers. For example, they nearly scored every time they had the ball has a very different meaning from they scored nearly every time they had the ball. Misplaced modifiers (nearly is the modifier in this example) don’t always change the meaning of the sentence this drastically, but they usually make the sentence harder to understand. For example, Joe read only 10 pages is preferable to Joe only read 10 pages, because the latter could be taken to mean that Joe did nothing but read 10 pages.

As a rule, a modifier should immediately precede the word it modifies.
Be careful with hyphenation rules for compound adjectives. A compound adjective is a combination of two or more words that function as a single adjective. The basic reason that we hyphenate them is to clarify meaning: 300-odd editors are (probably) not the same thing as 300 odd editors (credit to GrammarMonkeys for that one).

Hyphenation rules for compound adjectives include:
1. Hyphenate compound adjectives that precede the noun they modify: off-campus apartment, run-oriented offense, first-place finish.
  
  Note also that removing the hyphen from a compound adjective can create an alternate meaning: a small-state senator is senator in a state with a small population, while a small state senator is a state senator who is small. (Once you remove the hyphen, the two words are no longer a compound adjective, but two separate adjectives modifying the same noun.)
2. Do not hyphenate compound adjectives that follow the noun they modify: he had an apartment off campus, the offense was run oriented, they finished in first place.
3. Do not hyphenate a compound adjective that begins with an adverb ending in -ly: a carefully constructed play rather than a carefully-constructed play. (Technically, this isn’t really a compound adjective, but an adverb modifying an adjective that modifies a noun.)
  1. If the beginning word is an adverb that doesn’t end in -ly, the rules vary. For example, much-needed respite but least common multiple. And some adverbs can be hyphenated or not, depending on meaning: the most-satisfied customers are customers with the highest level of satisfaction, while the most satisifed customers is the largest number of satisfied customers.
4. This is only a partial list. Hyphenation is complicated, and proofreaders often have to look up exactly how to hyphenate compounds. The Chicago Manual of Style’s Hyphenation Table is a comprehensive reference. All of the rules apply equally to AP Style, except CMS rules about when to use the slightly wider n-dash (–) can be ignored, as AP Style only uses hyphens. When in doubt, look it up!

Be careful not to confuse words and phrases that sound similar. Your spell checker won’t help you with these! (For an amusing take on the limitations of the spell checker, see the satirical poem Ode to a Spell Checker.) This is a list of some commonly confused words, with some explanations of commonly mangled phrases. If you’re not sure of the difference between some of the listed words, please look them up in a dictionary. (Googling “definition [your word]” will give you a dictionary definition.)
1. Affect, effect
  1. This one is particularly complicated, because each one can be either a noun or a verb, and they all have different meanings. For more information, see Affect vs. Effect and 34 Other Common Confusions.
2. Allusion, illusion
3. Allude, elude
4. Assure, ensure, insure
5. Bait, bate
  1. In particular: bated breath, not baited breath.
6. Born, borne
7. Breath, breathe
8. Cache, cachet
9. Capital, capitol
10. Complement, compliment
11. Core, corps
  1. A corps is a body of people. So press corps, not press core.
12. Counsel, council
13. Criterion, criteria
  1. Criterion is the singular form of criteria.
14. Desert, dessert
  1. In particular: get one’s just deserts, not get one’s just desserts. (When desert is pronounced like dessert, it means something that is deserved.)
15. Discreet, discrete
16. Dew, do, due
  1. In particular: make do, not make due.
17. Fewer than, less than
  1. For more information, see Less vs. Fewer.
18. Gaff, gaffe
19. Gibe, jibe
20. Hoard, horde
21. Home, hone
  1. In particular: home in on, not hone in on. Although the latter is finding its way into accepted usage, it isn’t considered correct. See Hone/Home for more information.
22. Its, it’s
  1. Its is probably the most commonly misspelled word in English, probably at least in part because the apostrophe was dropped only about 200 years ago. For help on how to get it right, see When to Use It’s vs. Its.

Lay, lie
Lead, led
Loath, loathe
Loose, lose
1. It has recently become fairly common to incorrectly use loose in place of lose: loose weight, loose my keys, etc. Lose is a verb whose basic meaning is “no longer have.” Loose is an adjective meaning “not confined.” Where the confusion arises is that loose also has a somewhat archaic function as a verb, with the meaning of “turn loose” or “set free.” Probably the best-known example of this usage is He hath loosed the fateful lightning of his terrible swift sword, from The Battle Hymn of the Republic.
Moot, mute
1. In particular: moot point, not mute point.
Peak, peek, pique
1. In particular: pique one’s interest, not peek or peak one’s interest.
Phenomenon, phenomena
1. Phenomenon is the singular form of phenomena.
Pole, poll
1. In particular: pole position, not poll position. In horse racing, distances of 1/16th of a mile are marked with a pole. Starting nearest the pole, or at the innermost position on the track, is considered an advantage. Auto racing borrowed the term to mean the first starting position. The term has since broadened, especially in slang, to mean any advantageous position.
Principal, principle
Rain, reign, rein
1. In particular: free rein and take the reins, not free reign and take the reigns — a common error in our horse-deprived society.
Rational, rationale
Right, rite

In particular: rite of passage, not right of passage. This is easy to get wrong, because a “right of passage” makes logical sense in the sense of being allowed to go somewhere. But the term actually comes from the many ceremonies around passage into adulthood.

Sight, site
1. In particular: onsite or on-site, not onsight or on-sight, to mean “at a
  
  particular place.”
Straight, strait
1. In particular: dire straits and strait jacket, not dire straights and straight jacket.
Than, then
There, their, they’re
To, too, two
Toe, tow
1. In particular: toe the line, not tow the line.
Waive, wave
Wet, whet
1. In particular: whet one’s appetite, not wet one’s appetite.
Who’s, whose
Your, you’re

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Work Samples

JavaScript Object Creation Patterns

Object Factory Pattern

OLOO Pattern

Pseudo-Classical Pattern

ES6 Class

React/JavaScript: Tic-Tac-Toe Game (Play game)

App.js

Ruby: Blackjack Game

Python: Blackjack Game

Web Technologies: HTML5, CSS, jQuery, PHP, MySQL

vdrmodal.php, the modal dialog page

dialog() function code, from viewvendor.php

cdchildren.php: adds and removes child records

AddChild, RemChild, GetChildren and rsToJSON, from phpHelpers.php

cdbconnector.php: defines the CDbConnector class, used to connect to the MySQL database

getPartDists: MySQL proc to get parts for one distributor

C#: Multithreading, Reflection and Dynamic Binding, Using a RESTful Service

Program.cs

NorthWindDataRetrieve.cs

DataExport.cs

VB.Net: Multithreading, Using a RESTful Service

Program.vb

NorthwindDataRetrieve.vb

DataExport.vb

T-SQL: Various Examples

List all the tables and columns in the current database.

Run a group of (parameterless) stored procedures one after the other (in this case, a series of daily merge procs).

Pull data from a list of by-the-minute inspection results, roll them up on a per-hour basis, and pivot the results based on inspection type.

Use a transaction and dynamic SQL to perform an atomic read/write operation

List all reports in SSRS database by path, name and schema

VB6: Using CBT Hooking to Change the Layout of the Native MsgBox Function

VB6: Accessing the RichTextBox Control’s Underlying iRichTextOLE Interface

Blackjack Diagrams

Class Diagram

Main Flowchart

Subroutine: Calculate Hand Total

Subroutine: Check for Natural 21

Mixing BSCS: Preprocessing Logic

Mixing BSCS: Process Barcode Scan

PD Manager: Wireframe Sketch of Field Contact Entry Form

PPLS: Process Vendor RFQs

HealthCompare.com: Click-Through Commission Technical Design

UML: Documenting System Architecture and Behavior

AP Style Guide

AP Style and Punctuation Guide

Abbreviations

Capitalization

Dates and Times

Italics

Names of Persons

Numbers

Punctuation

Titles of Articles

AP Style Miscellanies

Common Writing Errors

Common Writing Errors

`dialog()` function code, from viewvendor.php

VB6: Accessing the RichTextBox Control’s Underlying `iRichTextOLE` Interface