LXXVI. Object property and method call overloading

Úvod

The purpose of this extension is to allow overloading of object property access and method calls. Only one function is defined in this extension, overload() which takes the name of the class that should have this functionality enabled. The class named has to define appropriate methods if it wants to have this functionality: __get(), __set() and __call() respectively for getting/setting a property, or calling a method. This way overloading can be selective. Inside these handler functions the overloading is disabled so you can access object properties normally.

Varovanie

Toto rozšírenie je EXPERIMENTÁLNE. Správanie tohto rozšírenia, vrátane názvov funkcií a všetkého ostatného, čo tu je zdokumentované, sa v budúcnosti môže bez ohlásenia zmeniť. Majte to na pamäti a používajte toto rozšírenie iba na vlastné nebezpečentsvo.

Požiadavky

These functions are available as part of the standard module, which is always available.

Inštalácia

In order to use these functions, you must compile PHP with the --enable-overload option. Starting with PHP 4.3.0 this extension is enabled by default. You can disable overload support with --disable--overload.

The windows version of PHP has built in support for this extension. You do not need to load any additional extension in order to use these functions.

Poznámka: Builtin support for overload is available with PHP 4.3.0.

Konfigurácia behu

This extension does not define any configuration directives.

Typy prostriedkov

This extension does not define any resource types.

Preddefinované konštanty

This extension does not define any constants.

Príklady

Some simple examples on using the overload() function:

Príklad 1. Overloading a PHP class

<?php

class OO
{
    var $a = 111;
    var $elem = array('b' => 9, 'c' => 42);

    // Callback method for getting a property
    function __get($prop_name, &$prop_value)
    {
        if (isset($this->elem[$prop_name])) {
            $prop_value = $this->elem[$prop_name];
            return true;
        } else {
            return false;
        }
    }

    // Callback method for setting a property
    function __set($prop_name, $prop_value)
    {
        $this->elem[$prop_name] = $prop_value;
        return true;
    }
}

// Here we overload the OO object
overload('OO');

$o = new OO;
print "\$o->a: $o->a\n"; // print: $o->a:
print "\$o->b: $o->b\n"; // print: $o->b: 9
print "\$o->c: $o->c\n"; // print: $o->c: 42
print "\$o->d: $o->d\n"; // print: $o->d:

// add a new item to the $elem array in OO
$o->x = 56; 

// instantiate stdclass (it is built-in in PHP 4)
// $val is not overloaded!
$val = new stdclass;
$val->prop = 555;

// Set "a" to be an array with the $val object in it
// But __set() will put this in the $elem array
$o->a = array($val);
var_dump($o->a[0]->prop);

?>

Varovanie

As this is an experimental extension, not all things work. There is no __call() support currently, you can only overload the get and set operations for properties. You cannot invoke the original overloading handlers of the class, and __set() only works to one level of property access.

Obsah
overload -- Enable property and method call overloading for a class