<?php//观察者模式//抽象主题类interface Subject{ public function attach(Observer $Observer); public function detach(Observer $observer); //通知所有注册过的观察者对象 public function notifyObservers();}//具体主题角色class ConcreteSubject implements Subject{ private $_observers; public function __construct() { $this->_observers = array(); } //增加一个观察者对象 public function attach(Observer $observer) { return array_push($this->_observers,$observer); } //删除一个已经注册过的观察者对象 public function detach(Observer $observer) { $index = array_search($observer,$this->_observers); if($index === false || !array_key_exists($index, $this->_observers)) return false; unset($this->_observers[$index]); return true; } //通知所有注册过的观察者 public function notifyObservers() { if(!is_array($this->_observers)) return false; foreach($this->_observers as $observer) { $observer->update(); } return true; }}//抽象观察者角色interface Observer{ //更新方法 public function update();}//观察者实现class ConcreteObserver implements Observer{ private $_name; public function __construct($name) { $this->_name = $name; } //更新方法 public function update() { echo 'Observer'.$this->_name.' has notify'; }}$Subject = new ConcreteSubject();//添加第一个观察者$observer1 = new ConcreteObserver('baixiaoshi');$Subject->attach($observer1);echo 'the first notify:';$Subject->notifyObservers();//添加第二个观察者$observer2 = new ConcreteObserver('hurong');echo '<br/>second notify:';$Subject->attach($observer2);/*echo $Subject->notifyObservers();echo '<br/>';$Subject->notifyObservers();*/?>
运行结果：
the first notify:Observerbaixiaoshi has notify second notify:
