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108 lines
2.3 KiB
Plaintext
108 lines
2.3 KiB
Plaintext
Title: Delegation
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(a/k/a. Object-Based Inheritance)
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Version: $Revision$
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Status: draft
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Maintainer: Sebastian Bergmann <sb@sebastian-bergmann.de>
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Dynamic Delegation
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Syntax / Example
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<?php
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class aDelegatee {
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function doSomething() {
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echo 'hubu';
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}
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}
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class anotherDelegatee {
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function doSomething() {
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echo 'tubu';
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}
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}
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class Foo {
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delegatee $bar;
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function setDelegatee($delegatee) {
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$this->delegatee = $delegatee;
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}
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}
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$foo = new Foo;
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$foo->setDelegatee(new aDelegatee);
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$foo->doSomething(); /* prints "hubu" */
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$foo->setDelegatee(new anotherDelegatee);
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$foo->doSomething(); /* prints "tubu" */
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?>
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Semantics / Synopsis
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The "Foo" class may use all methods available in "$bar" as if they
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where locally defined or inherited from a superclass. The essential
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difference is that by assigning another object to "$bar" it is
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possible to dynamically switch between different implementations for
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these methods.
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Fixed Delegation
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Syntax / Example
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<?php
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class aDelegatee {
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function doSomething() {
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echo 'hubu';
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}
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}
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class Foo {
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final delegatee $bar = new aDelegatee;
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}
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$foo = new Foo;
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$foo->doSomething(); /* prints "hubu" */
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?>
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Semantics / Synopsis
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The "Foo" class may use all methods available in "$bar" as if they
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where locally defined or inherited from a superclass. The difference
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to the dynamic delegation is that once the delegatee object is set,
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it cannot be changed.
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Default Delegation
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Syntax / Example
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<?php
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class Foo {
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function __delegate($name, $parameters = array()) {
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echo $name;
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}
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}
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$foo = new Foo;
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$foo->bar(); /* prints "bar" */
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?>
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Semantics / Synopsis
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If a class has a __delegate() method, it is called whenever a
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method on an object of this class is called that is
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* Not defined in the class.
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* Not provided by a delegatee object.
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The __delegate() method is called with the name and parameters
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of the method call.
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This supersedes / obsoletes similar functionality introduced in
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Zend Engine 1 by ext/overload.
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