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();


 ?>