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This document uses PHP Chinese website manual Release
(PHP 5 >= 5.1.0)
The SplSubject interface is used alongside SplObserver to implement the Observer Design Pattern.
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)[#1] aiddroid at example dot com [2013-07-02 07:01:56]
class Newspaper implements \SplSubject{
private $name;
private $observers = array();
private $content;
public function __construct($name) {
$this->name = $name;
}
//add observer
public function attach(\SplObserver $observer) {
$this->observers[] = $observer;
}
//remove observer
public function detach(\SplObserver $observer) {
$key = array_search($observer,$this->observers, true);
if($key){
unset($this->observers[$key]);
}
}
//set breakouts news
public function breakOutNews($content) {
$this->content = $content;
$this->notify();
}
public function getContent() {
return $this->content." (by {$this->name})";
}
//notify observers(or some of them)
public function notify() {
foreach ($this->observers as $value) {
$value->update($this);
}
}
}
class Reader implements SplObserver{
private $name;
public function __construct($name) {
$this->name = $name;
}
public function update(\SplSubject $subject) {
echo $this->name.' is reading breakout news <b>'.$subject->getContent().'</b><br>';
}
}
//classes test
$newspaper = new Newspaper('Newyork Times');
$allen = new Reader('Allen');
$jim = new Reader('Jim');
$linda = new Reader('Linda');
//add reader
$newspaper->attach($allen);
$newspaper->attach($jim);
$newspaper->attach($linda);
//remove reader
$newspaper->detach($linda);
//set break outs
$newspaper->breakOutNews('USA break down!');
//=========output==========
//Allen is reading breakout news USA break down! (by Newyork Times)
//Jim is reading breakout news USA break down! (by Newyork Times)
[#2] Anonymous [2013-05-07 10:37:44]
<?php
class Observable implements SplSubject
{
private $storage;
function __construct()
{
$this->storage = new SplObjectStorage();
}
function attach(SplObserver $observer)
{
$this->storage->attach($observer);
}
function detach(SplObserver $observer)
{
$this->storage->detach($observer);
}
function notify()
{
foreach ($this->storage as $obj) {
$obj->update($this);
}
}
//...
}
abstract class Observer implements SplObserver
{
private $observable;
function __construct(Observable $observable)
{
$this->observable = $observable;
$observable->attach($this);
}
function update(SplSubject $subject)
{
if ($subject === $this->observable) {
$this->doUpdate($subject);
}
}
abstract function doUpdate(Observable $observable);
}
class ConcreteObserver extends Observer
{
function doUpdate(Observable $observable)
{
//...
}
}
$observable = new Observable();
new ConcreteObserver($observable);
[#3] przemyslaw dot szpiler at gmail dot com [2012-02-26 21:54:34]
<?php
// Example implementation of Observer design pattern:
class MyObserver1 implements SplObserver {
public function update(SplSubject $subject) {
echo __CLASS__ . ' - ' . $subject->getName();
}
}
class MyObserver2 implements SplObserver {
public function update(SplSubject $subject) {
echo __CLASS__ . ' - ' . $subject->getName();
}
}
class MySubject implements SplSubject {
private $_observers;
private $_name;
public function __construct($name) {
$this->_observers = new SplObjectStorage();
$this->_name = $name;
}
public function attach(SplObserver $observer) {
$this->_observers->attach($observer);
}
public function detach(SplObserver $observer) {
$this->_observers->detach($observer);
}
public function notify() {
foreach ($this->_observers as $observer) {
$observer->update($this);
}
}
public function getName() {
return $this->_name;
}
}
$observer1 = new MyObserver1();
$observer2 = new MyObserver2();
$subject = new MySubject("test");
$subject->attach($observer1);
$subject->attach($observer2);
$subject->notify();
$subject->detach($observer2);
$subject->notify();
?>