User.php

<?php
/**
 * Created by PhpStorm.
 * User: 小粽子
 * Date: 2018/12/19
 * Time: 11:15
 */

namespace DesignPattern\Behavioral\Observer;

use SplObserver;

class User implements \SplSubject
{

    public $observers;
    protected $data = [];

    public function __construct()
    {
        $this->observers = new \SplObjectStorage();
    }

    public function attach(SplObserver $observer)
    {
        $this->observers->attach($observer);
    }

    public function detach(SplObserver $observer)
    {
        $this->observers->detach($observer);
    }

    public function notify()
    {
        foreach ($this->observers as $observer) {
            $observer->update($this);
        }
    }

    public function __set($name, $value)
    {
        $this->data[$name] = $value;

        // 通知观察者用户被改变
        $this->notify();
    }
}