PHP实现观察者模式

<?php
       //php设计模式观察者模式
 
        /**
          被观察者
        */
 
      class user implements  SplSubject{
            public $lognum;
            public $hobby;
 
            protected $observers=null;
            public function __construct($hobby){
                $this->lognum=rand(1,10);
                $this->hobby=$hobby;
                $this->observers=new SplObjectStorage();
            }
            public function login(){
                 $this->notify();
            }
            public function attach(SplObserver $observer){
               $this->observers->attach($observer);
            }
            public function detach(SplObserver $observer){
 
               $this->observers->detach($observer);
            }
 
            public function notify(){
               $this->observers->rewind();
               while($this->observers->valid()){
                  $observer=$this->observers->current();
                  $observer->update($this);
                  $this->observers->next();
               }
            }
      }
          /**
          *  观察者
          */
      class secrity implements SplObserver{
           public function update(SplSubject $subject){
                  if($subject->lognum<3){
                      echo '这是第'.$subject->lognum.'次安全登录';
                  }else{
                      echo '这是第'.$subject->lognum.'次登录,异常';
                  }
           }
      }
      class ad implements SplObserver{
           public function update(SplSubject $subject){
             if($subject->hobby=='sports'){
                 echo '台球英锦赛门票预订';
             }else{
                 echo '好好学习天天向上';
             }
           }
      }
     //实施观察
        $user=new user('study');
        $user->attach(new secrity());
        $user->attach(new ad());
        $user->login();
 
 ?>

观察者模式属于行为模式，是定义对象间的一种一对多的依赖关系，以便当一个对象的状态发生改变时，所有依 赖于它的对象都得到通知并自动刷新。它完美的将观察者对象和被观察者对象分离。可以在独立的对象（主体）中维护一个对主体感兴趣的依赖项（观察器）列表。 让所有观察器各自实现公共的 Observer 接口，以取消主体和依赖性对象之间的直接依赖关系。

实例Ⅱ

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;
    }
}
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();
    }
}
$observer1 = new MyObserver1();
$observer2 = new MyObserver2();
 
$subject = new MySubject("test");
 
$subject->attach($observer1);
$subject->attach($observer2);
$subject->notify();