PHP 观察者设计模式测试代码笔记

<?php/** * 所有观察者必须实现的接口 * Interface Observer */interface Observer {    public function update();}/** * 观察者1 * Class sendEmail */class SendEmail implements Observer {    public function update()    {        echo 'the email has been send <br>';    }}/** * 观察者2 * Class SaveName */class SaveName implements Observer {    public function update()    {        echo 'the name has been save <br>';    }}/** * 被观察者接口 * Interface Observered */interface  Observered {    public function attach($object);    public function delete($object);    public function notify();}/** * 被观察者 * Class User */class User implements Observered {    public $observers = array();    /**     * 注册观察者     * @param $object     */    public function attach($object)    {        if (!is_object($object)) {            exit('it is not an object');        }        if ($object instanceof Observer) {            if (!in_array($object,$this->observers)) {                $this->observers[] = $object;            }        } else {            echo get_class($object) . ' is disable <br>';        }    }    /**     * 删除观察者     * @param $object     */    public function delete($object)    {        if (in_array($object,$this->observers)) {            $index = array_search($object,$this->observers);            unset($this->observers[$index]);        }    }    /**     * 通知所有观察者     */    public function notify()    {        foreach ($this->observers as $val) {            $val->update();        }    }    /**     * 被观察者自己的业务     */    public function printName()    {        echo 'I have been observing <br>';    }}    $object = new User();    $object->attach(new SendEmail()); //注册观察者1    $object->attach(new SaveName());  //注册观察者2    $object->printName();             //被观察者自己的业务    $object->notify();                //通知所有的观察者