本文实例讲述了PHP观察者模式。分享给大家供大家参考，具体如下：
<?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:
希望本文所述对大家PHP程序设计有所帮助。
