facade.php

<?php
/**
 * 外观模式
 *
 * 体现了封装的思想，将多个子系统的封装起来，提供一个简洁的接口供外部调用。在我们编程的过程中你不知不觉已经在使用这种设计模式
 */
class Goods {

    private $num=1;
    private $price=12;

    public function consumerStock($num)
    {
        $this->num = $num;
        echo "消耗库存：".$num.PHP_EOL;
    }

    public function getPrice()
    {
        return $this->price;
    }

    public function getScores()
    {
        return $this->price * $this->num;
    }

}

class User
{
    public function addScores(Goods $goods)
    {
        echo "用户获得：".$goods->getScores()."积分";
    }
}

class Order {

    private $goods;
    private $user;
    public function __construct(Goods $goods, User $user)
    {
        $this->goods = $goods;
        $this->user = $user;
    }

    public function create($num)
    {
        $this->goods->consumerStock($num);
        $this->user->addScores($this->goods);
    }
}

$order = new Order(new Goods(), new User());
$order->create(2);