####观察者模式* 设计观察者是为了让一个对象跟踪某个状态,知道状态如何改变,一旦状态改变,所有订阅的对象都能得到通知#####使用SPL实现观察者模式* Splsubject 接口有三个抽象方法 attach(),detach(),notify()这些方法不返回任何结果* SplObserver 接口有一个方法update()它会得到subject状态的最新状态并交给观察者实例* SplObjectStorage 类描述为从对象到数据或对象集的一个映射```<?php/** * Created by PhpStorm. * User: gewenrui * Date: 16/3/14 * Time: 下午7:46 *///继承Splsubject接口class ConcreteSubject implements SplSubject{ private $observers; private $data; //实例化仓库 public function setObservers(){ $this->observers = new SplObjectStorage(); } //添加观察者 public function attach(\SplObserver $observer){ $this->observers->attach($observer); } //删除观察者 public function detach(\SplObserver $observer){ $this->observers->detach($observer); } //通知转发 public function notify(){ foreach($this->observers as $observer){ $observer->update($this); } } //设置数据 public function setData($dataNow){ $this->data = $dataNow; } public function getData(){ return $this->data; }}//SPL具体观察者class ConcreteObserver implements SplObserver{ public function update(SplSubject $subject) { echo $subject->getData(); }}class Client{ public function __construct() { echo "<p> create three new concrete observers "; //创建观察者 $ob1 = new ConcreteObserver(); $ob2 = new ConcreteObserver(); $ob3 = new ConcreteObserver(); $subject = new ConcreteSubject(); $subject->setObservers(); $subject->setData("here is u data"."</br>"); $subject->attach($ob1); $subject->attach($ob2); $subject->attach($ob3); $subject->notify(); echo "<p> Reset data and reattach ob3</p>"; $subject->setData("more data that only"."</br>"); $subject->attach($ob3); $subject->attach($ob2); $subject->notify(); }}$data = new Client();```#####自由的PHP和观察者模式```<?php/** * Created by PhpStorm. * User: gewenrui * Date: 16/3/14 * Time: 下午8:24 */namespace abbbbb;//一个接口,一个抽象类,一个继承抽象类的具体类//观察者实体实现借口类interface Observer{ function update(Subject $subject);}abstract class Subject{ protected $stateNow; protected $observers = array(); public function attachObser(Observer $obser){ //array_push() 函数向第一个参数的数组尾部添加一个或多个元素（入栈），然后返回新数组的长度。 array_push($this->observers,$obser); } public function detachObser(Observer $obser){ //从数组中移除 数据 $position = 0; foreach($this->observers as $viwer){ ++$position; if($viwer == $obser){ array_splice($this->observers,($position),1); } } } public function notify(){ foreach($this->observers as $viewer){ //调用update方法 $viewer->update($this); } }}class ConcreteSubject extends Subject{ public function setState($stateSet){ $this->stateNow = $stateSet; } public function getState(){ return $this->stateNow; }}class ConcreteObserverDT implements Observer{ private $currentState; public function update(Subject $subject) { $this->currentState = $subject->getState(); echo "DT"; }}class ConcreObserverTablet implements Observer{ private $currentState; public function update(Subject $subject) { $this->currentState = $subject->getState(); echo "tablet"; }}class ConcreObserverPhone implements Observer{ private $currentState; public function update(Subject $subject) { $this->currentState = $subject->getState(); echo "phone"; }}class Client{ public function __construct() { $sub = new ConcreteSubject(); $ob1 = new ConcreObserverPhone(); $ob2 = new ConcreObserverTablet(); $ob3 = new ConcreteObserverDT(); $sub->attachObser($ob1); $sub->attachObser($ob2); $sub->attachObser($ob3); $sub->setState("fuck"); $sub->detachObser($ob1); $sub->notify(); }}$data = new Client();```登录后复制
