<?php
//觀察者設(shè)計(jì)模式能夠更便利創(chuàng)建和查看目標(biāo)對(duì)象狀態(tài)的對(duì)象，并且提供和核心對(duì)象非耦合的置頂功能性。
//觀察者設(shè)計(jì)模式非常常用，在一般復(fù)雜的WEB系統(tǒng)中，觀察者模式可以幫你減輕代碼設(shè)計(jì)的壓力，降低代碼耦合。
//以一個(gè)購物流程為例子
class order {
    protected $observers = array(); // 存放觀察容器
    //觀察者新增
    public function addObServer($type, $observer) {
        $this->observers[$type][] = $observer;
    }
    //運(yùn)行觀察者
    public function obServer($type) {
        if (isset($this->observers[$type])) {
            foreach ($this->observers[$type] as $obser) {
                $a = new $obser;
                $a->update($this); //公用方法
            }
        }
    }
    //下單購買流程
    public function create() {
        echo '購買成功';
        $this->obServer('buy'); // buy動(dòng)作
    }
}
class orderEmail {
    public static function update($order) {
        echo '發(fā)送購買成功一個(gè)郵件';
    }
}
class orderStatus {
    public static function update($order) {
        echo '改變訂單狀態(tài)';
    }
}
$ob = new order;
$ob->addObServer('buy', 'orderEmail');
$ob->addObServer('buy', 'orderStatus');
$ob->create();

<?php
// 主題接口
interface Subject{
  public function register(Observer $observer);
  public function notify();
}
// 觀察者接口
interface Observer{
  public function watch();
}
// 主題
class Action implements Subject{
   public $_observers=array();
   public function register(Observer $observer){
     $this->_observers[]=$observer;
   }
   public function notify(){
     foreach ($this->_observers as $observer) {
       $observer->watch();
     }
   }
 }
// 觀察者
class Cat implements Observer{
   public function watch(){
     echo "Cat watches TV<hr/>";
   }
 } 
 class Dog implements Observer{
   public function watch(){
     echo "Dog watches TV<hr/>";
   }
 } 
 class People implements Observer{
   public function watch(){
     echo "People watches TV<hr/>";
   }
 }
// 應(yīng)用實(shí)例
$action=new Action();
$action->register(new Cat());
$action->register(new People());
$action->register(new Dog());
$action->notify();