菜鸟带你看传说中的观察者模式！

<?php

class Wechat
{
    private $subscribers = array();

    public function register(Subscriber $subscriber)
    {
        $this->subscribers[] = $subscriber;
    }

    public function pushMessage($message)
    {
        foreach($this->subscribers as $subscriber)
        {
            $subscriber->getMessage($message);
        }
    }
}

interface Subscriber
{
    public function getMessage($message);
}

class Evelin implements Subscriber
{
    public function getMessage($message)
    {
        echo 'Evelin: '. $message;
    }
}

class Anke implements Subscriber
{
    public function getMessage($message)
    {
        echo 'Anke: '. $message;
    }
}

$wechat = new Wechat();
$evelin = new Evelin();
$anke = new Anke();

$wechat->register($evelin);
$wechat->register($anke);
$wechat->pushMessage('发新消息啦！');