• 观察者模式

<?php
class dingdaguo
{
     protected $observers = [];
     public function addobserver($myobserver)
     {
        $this->observers[] = $myobserver;
     }
     public function drink_cola()
     {
        foreach($this->observers as $observer)
        {
            $observer->persuade();
        }
     }
     public function delobsrver($observer)
     {
         $index = array_search($observer,$this->observers,);
         $this->observers=array_slice($this->observers,0,$index);
     }
}

class coach
{
    public function __construct($name)
    {
        $this->name = $name;
    }

    public function persuade()
    {
        echo $this->name."说:别喝可乐了，都是甜的东西".PHP_EOL;
    }
}
$cpc = new coach("陈培昌");
$cj = new coach("程劲");
$dy = new dingdaguo();
$dy->addobserver($cpc);
$dy->addobserver($cj);
$dy->drink_cola();
echo "删除其中一个对象".PHP_EOL;
$dy->delobsrver($cj); 
$dy->drink_cola();

输出结果:

陈培昌说:别喝可乐了，都是甜的东西
程劲说:别喝可乐了，都是甜的东西
删除其中一个对象
陈培昌说:别喝可乐了，都是甜的东西