PHP 手冊
後退前進


XCV. Object property and method call overloading

簡介

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.

警示

本增加模組是實驗性的。本模組的行為，內含其函數的名稱以及其它任何關於此模組的文件可能會在沒有知會的情況下隨 PHP 以後的發佈而改變。使用本增加模組風險自擔。

警示

This extension is not a part of PHP 5. PHP 5 supports __get(), __set() and __call() natively. See the Overloading in PHP 5 page for more information.

需求

要編譯本增加模組無需外部庫檔案。

安裝

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.

PHP 的 Windows 版本已經內建該增加模組的支援。無需加載任何附加增加庫即可使用這些函數。

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

運行時配置

本增加模組在 php.ini 中未定義任何配置選項。

資源類型

本增加模組未定義任何資源類型。

預定義常量

本增加模組未定義任何常量。

範例

Some simple examples on using the overload() function:

例子 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;
echo "\$o->a: $o->a\n"; // print: $o->a: 111
echo "\$o->b: $o->b\n"; // print: $o->b: 9
echo "\$o->c: $o->c\n"; // print: $o->c: 42
echo "\$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);

?>

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


後退起點前進
deaggregate上一級overload