php 燕十八 观察者模式代码例子

<?php
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();//操作session
    }
    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();
        }
    }
}


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,危险";
        }
    }
}

class ad implements SPLObserver
{

    public function update(SplSubject $subject)
    {
        if($subject->hobby=="sports")
        {
            echo "台球赛门票预定";
        }else
        {
            echo "还是好好学习吧";
        }
    }
}

$user=new user("study");
$user->attach(new secrity());
$user->attach(new ad());
$user->login();
?>