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File: autoboxExample_TypeEnforcing.php

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  Classes of Artur Graniszewski  >  Java and C# compatible object autoboxing for PHP  >  autoboxExample_TypeEnforcing.php  >  Download  
File: autoboxExample_TypeEnforcing.php
Role: Example script
Content type: text/plain
Description: Example script: type enforcing, mathematical operations on integer _objects_
Class: Java and C# compatible object autoboxing for PHP
Wrap string and integer values in objects
Author: By
Last change:
Date: 4 years ago
Size: 5,405 bytes
 

Contents

Class file image Download
<?php

/**
 * JAVA Autoboxing (part of Lotos Framework)
 *
 * Copyright (c) 2005-2010 Artur Graniszewski (aargoth@boo.pl)
 * All rights reserved.
 *
 * @category Library
 * @package Lotos
 * @subpackage DataTypes
 * @copyright Copyright (c) 2005-2010 Artur Graniszewski (aargoth@boo.pl)
 * @license GNU LESSER GENERAL PUBLIC LICENSE Version 3, 29 June 2007
 * @version $Id$
 */

 
// load required library
include("./variablesManager.php");

  
/**
 * Example class.
 *
 * Note: in order to use AutoBoxing, your class need to extend "AutoBoxedObject" class.
 */
class Integer extends AutoBoxedObject
{
    public
$value = 0;
   
    public function
__construct($value) {
       
       
// TYPE ENFORCING
       
if($value && !is_int ($value) && !is_float($value)) {
            throw new
Exception('The new value is not an Integer!!!');
        }
       
       
$this->value = (int)$value;
    }
   
    public function
__toString() {
       
// NOTE: this must be a string, PHP forbids returning different type of variables in __toString() methods.
       
return "{$this->value}";
    }
   
    public function
toHex() {
       
$x = strtoupper(dechex($this->value));
       
$y = ceil(strlen($x) / 2);
        return
str_pad($x, $y * 2, '0', STR_PAD_LEFT);
    }
}

/**
* Initializes a newly created Integer object.
* @return Integer created String object
*/
function & integer($value = null) {
   
$x = & VariablesManager::getNewPointer(new Integer($value));
    return
$x;
}

// 1) We're setting $x as an Integer object
$x = & integer();

// 2) Now we are changing $x value to 10
// NOTE: PHP without enabled autoboxing would destroy the Integer object and set $x as simple integer type
$x = 10;

// 3) Now we are checking, that $x is still an object
echo "<h3>Integer autoboxing:</h3>";
echo
'The initial value of $x variable is "'.$x.'"<br />';
echo
'The initial datatype of $x variable is '.gettype($x).(is_object($x) ? ' ('.get_class($x).')': '').'<br />';
// this line would raise FATAL_ERROR withou autoboxing:
echo 'The hex value of $x is 0x'.$x->toHex().'<br />';

// 4) Now we are trying to change $x value to a invalid integer value
echo "<h3>Type enforcing:</h3>";
try {
   
$x = "aaaa"; // invalid value, valid integer should contain digits only
} catch (Exception $e) {
    echo
'Exception detected: Cannot change the integer value of $x to "aaaa", the new value should contain digits only<br />';
    echo
"Original exception message: ".$e->getMessage()."<br />";
}



// 5) Lets do some math...
echo "<h3>Basic math:</h3>";

echo
'<strong>Impossible becomes possible: adding two objects in PHP</strong>:<br />';
$x = & integer(0);
$y = & integer(10);
$z = & integer(20);

// PLEASE NOTE the quotes surrounding the variables names, without it PHP would return '1' instead the true
// value of integers objects (because it would not use __toString() method to do the math!)
$x = "$y" + "$z" + 5;
echo
'The initial value of $y variable is "'.$y.'"<br />';
echo
'The initial datatype of $y variable is '.gettype($y).(is_object($y) ? ' ('.get_class($y).')': '').'<br />';
echo
'The initial value of $z variable is "'.$z.'"<br />';
echo
'The initial datatype of $z variable is '.gettype($z).(is_object($z) ? ' ('.get_class($z).')': '').'<br />';
echo
'<u>The result of $x = $y + $z + 5 is "'.$x.'"</u><br />';
echo
'The datatype of $x (sum) variable is '.gettype($x).(is_object($x) ? ' ('.get_class($x).')': '').'<br />';
// this line would raise a FATAL_ERROR without autoboxing enabled:
echo 'The hex value of $x is 0x'.$x->toHex().'<br />';


echo
'<br /><strong>We can also do other math operations, for example divide two objects: </strong><br />';
$x = & integer(0);
$y = & integer(20);
$z = & integer(10);

// PLEASE NOTE the quotes surrounding the variables names, without it PHP would return '1' instead the true
// value of integers objects (because it would not use __toString() method to do the math!)
$x = "$y" / "$z";

echo
'The initial value of $y variable is "'.$y.'"<br />';
echo
'The initial value of $z variable is "'.$z.'"<br />';
echo
'<u>The result of $x = $y / $z is "'.$x.'"</u><br />';
echo
'The hex value of $x is 0x'.$x->toHex().'<br />';

echo
'<br /><strong>This behaviour gives us some new C-like functionality</strong><br />';
$x = & integer(0);
$y = & integer(20);
$z = & integer(7);

// PLEASE NOTE the quotes surrounding the variables names, without it PHP would return '1' instead the true
// value of integers objects (because it would not use __toString() method to do the math!)
$x = "$y" / "$z";

echo
'The initial value of $y variable is "'.$y.'"<br />';
echo
'The initial value of $z variable is "'.$z.'"<br />';
echo
'<u>The result of $x = $y / $z is "'.$x.'"</u><br />';
echo
'The hex value of $x is 0x'.$x->toHex().'<br />';

echo
"Why 2.00 and not 2.85? Because in C and C# operation: 20 / 7 = 2.85 converted to int becomes 2<br />";
echo
"Ofcourse you can freely change this behaviour in your custom Integer class<br />";

echo
"<h3>Remember, you can easily create your own data types, like float, double, utf-8 string, etc.!</h3>";
echo
"...using this mechanism you can even try to override default mathematical operators like +/*-!<br />";