职责链模式(Chain of Responsibility Pattern)

<?php//职责链模式//顾客类class Customer {//菜名private $orderName;//get set 方法public function __set($key, $value) {$this->$key = $value;}public function __get($key) {if(isset($this->$key)) {return $this->$key;} else {return NULL;}}}//雇员类abstract class Employee {//雇员姓名protected $name;//职责链下一环protected $successor;public function __construct($name) {$this->name = $name;}//设定职责链下一环public function setSuccessor(Employee $successor) {$this->successor = $successor;}//处理任务转交任务给下一职责人public function handleRequest(Customer $customer) {if(!empty($this->successor)) {$this->successor->handleRequest($customer);}}}//服务生class Server extends Employee {}//主厨class Chef extends Employee {public function handleRequest(Customer $customer) {//判断是否自己职责所在if($customer->orderName == '农家小炒肉') {echo $this->name.'做了'.$customer->orderName.'<br/>';} else {//调用父类方法（父类的判断等代码不用重复写）parent::handleRequest($customer);}}}//二等厨师class AssistantChef extends Employee {public function handleRequest(Customer $customer) {if($customer->orderName == '酸辣土豆丝') {echo $this->name.'做了'.$customer->orderName.'<br/>';} else {parent::handleRequest($customer);}}}//实例化雇员$server = new Server('张三');$chef = new Chef('李四');$assistantChef = new AssistantChef('王五');//定义职责链$server->setSuccessor($chef);$chef->setSuccessor($assistantChef);//实例化顾客类$customer = new Customer();//点菜$customer->orderName = '酸辣土豆丝';//给服务员（职责链开始）$server->handleRequest($customer);$customer->orderName = '农家小炒肉';$server->handleRequest($customer);?>