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LXXVI. Object property and method call overloadingEinf�hrung
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.
Warnung | Diese Erweiterung ist
EXPERIMENTELL. Das Verhalten dieser Erweiterung,
einschlie�lich der Funktionsnamen, und alles Andere was hier dokumentiert
ist, kann sich in zuk�nftigen PHP-Versionen ohne Ank�ndigung �ndern. Seien
Sie gewarnt und verwenden Sie diese Erweiterung auf eigenes Risiko.
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AnforderungenDiese Erweiterung ben�tigt zur Erstellung keine externen Bibliotheken. Installation
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. Anmerkung:
Builtin support for overload is available with PHP 4.3.0.
Laufzeit KonfigurationDiese Erweiterung definiert keine Konfigurationseinstellungen in der php.ini. Resource TypenDiese Erweiterung definiert keine Resource-Typen. Vordefinierte KonstantenDiese Erweiterung definiert keine Konstanten. Beispiele
Some simple examples on using the overload()
function:
Beispiel 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);
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Warnung |
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.
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- Inhaltsverzeichnis
- overload -- Enable property and method call overloading for a class
User Contributed Notes Object property and method call overloading |
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steve at walkereffects dot com
25-Feb-2003 05:32 |
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If you are a perfectionist when it comes to your class interfaces, and you
are unable to use overload(), there is another viable solution:
Use
func_num_args() to determine how many arguments were sent to the function
in order to create virtual polymorphism. You can create different
scenarios by making logical assumptions about the parameters sent. From
the outside the interface works just like an overloaded
function.
The following shows an example of overloading a class
constructor:
class Name { var $FirstName; var
$LastName;
function Name($first, $last) {
$numargs = func_num_args(); if($numargs >=
2) { $this->FirstName = $first;
$this->LastName = $last; }
else { $names = explode($first);
$this->FirstName = $names[0];
$this->LastName = $names[1] } } }
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muell-spam-trash-abfall at kcet dot de
14-Mar-2003 02:53 |
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This is the syntax of __get(), __set() and __call():
__get ( [string
property_name] , [mixed return_value] ) __set ( [string property_name]
, [mixed value_to_assign] ) __call ( [string method_name] , [array
arguments] , [mixed return_value] )
__call() seems to work with PHP
4.3.0
See
for using this extension in detail.
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