<?php
class Newspaper implements SplSubject {
private $name;
private $observers;
private $content;
public function __construct($name){
$this->$name = $name;
$this->observers = new SplObjectStorage();
}
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 getContent(){
return $this->content."{$this->name}";
}
public function breakOutNews($content) {
$this->content = $content;
$this->notify();
}
}
<?php
class Reader implements SplObserver {
private $name;
public function __construct($name){
$this->name = $name;
}
public function update(SplSubject $subject) {
echo $this->name.' is reading breakout news'.$subject->getContent();
}
}
<?php
include "Newspaper.php";
include "Reader.php";
class WorkFlow {
public function run() {
$newspaper = new Newspaper('New York Times');
$allen = new Reader("allen");
$jimmy = new Reader("jimmy");
$tom = new Reader("tom");
$newspaper->attach($allen);
$newspaper->attach($jimmy);
$newspaper->attach($tom);
$newspaper->detach($tom);
$newspaper->breakOutNews('USA BREAK DOWN');
}
}
$work = new WorkFlow();
$work->run();
newspaper是被观察的对象，reader是观察者。当报纸发布消息， 每一个用户都会得到通知。这就是观察者模式的使用场景。
