观察者模式用于监听关联类的行为,如果有所异常并作出回应;

<?php
    //观察者模式:一个类的行为(方法)被另外一个类的行为(方法)所观察甚至限制

    //男人类:大丈夫有两个行为,加入女朋友监察和自行购物行为
    class Man{
        private $observer=array();

        //加入观察者对象
        public function addObserver($observer)
        {
            $this->observer[] = $observer;
        }

        public function buy()
        {
            foreach($this->observer as $observer){
                //在男人购买方法中加入女朋友对象来观察监听男人的消费
                $observer->dongjie();
            }
        }

        //移除观察者
        public function delObserver($observer)
        {
            $key = array_search($observer,$this->observer);

            array_splice($this->observer,$key,1);
        }
    }

    //女朋友类有个自发行为:冻结男朋友的消费卡的行为
    class GirlFriend{
        private $name;
        function __construct($name)
        {
            $this->name = $name;
        }

        public function dongjie()
        {
            echo $this->name."说道想偷偷花钱买东西,没门!<br />";
        }
    }


    $xiaoli = new GirlFriend('小丽');
    //var_dump($xiaoli);die();
    $xiaohua = new GirlFriend('小花');
    $xiaoming = new Man();
    $xiaoming->addObserver($xiaoli);
    $xiaoming->addObserver($xiaohua);
    $xiaoming->delObserver($xiaohua);
    $xiaoming->buy();

code.php