<?php/*这个代码的功能类似于查数据，先到memcahce查，没有的话再去mysql查。*/class Request {    //发起请求的类，只是测试用，跟责任链模式无关    public $forDebugOnly;    public $action;    public $key;    public $response;}abstract class Handler {                    //处理数据抽象类    private $successor = null; //后继者    final public function append(Handler $handler) {        if (is_null($this->successor)) {            $this->successor = $handler; //添加下一个链        } else {            $this->successor->append($handler);  //有下一个链再为下一个链添加链        }    }    final public function handle(Request $req) {   //处理请求的方法        $req->forDebugOnly = get_called_class();  //判断具体是哪一个类调用，跟责任链模式无关。        $processed = $this->processing($req);        if (!$processed) {            // the request has not been processed by this handler => see the next            if (!is_null($this->successor)) {                $processed = $this->successor->handle($req);            }        }        return $processed;    }    abstract protected function processing(Request $req);}class FastStorage extends Handler {         //快速处理数据类    protected $data = http://www.mamicode.com/array();"\n"; //happyecho $request->forDebugOnly."\n"; //FastStorage$request->key = ‘20141019‘;    //在发起一个快存贮没有的数据请求，快存贮会找下一个链来处理$result = $storageChain->handle($request);echo $request->response."\n"; //luckyecho $request->forDebugOnly."\n"; //SlowStorage