设计模式实例:中介模式实现打赏功能

实现功能:

1.用户A向用户B打赏金币

2.减少用户A的金币,并写入金币明细表

3.增加用户B的金币,并写入金币明细表

4.给用户B发送一个打赏通知

ps:本文中的同事,并非是指该类为同事,而是沿用中介者模式中的称呼.与中介者打交道的各个类.

一.虚拟同事类:

/**
 * Class Colleague
 */
abstract class Colleague
{
    protected $mediator;

    public function setMediator(Mediator $mediator)
    {
        $this->mediator = $mediator;
    }
}

　　

二.虚拟用户类,继承虚拟同事类

/**
 * Class User
 */
abstract class User extends Colleague
{
    protected $uid;
    protected $money;

    public function __construct($uid, $money)
    {
        $this->uid      = $uid;
        $this->money    = $money;
    }
}

　　

三.创建两个同事类:付款方和收款方

1.付款方

class UserPayer extends User
{
    public function changeMoney($money)
    {
        $this->money -= $money;

        // 写入明细
        $this->mediator->writeMoneyDetail([
            'uid'   => $this->uid,
            'money' => $money,
            'rule'  => '-'
        ]);

        // 付款给对方
        $this->mediator->payee($money);
    }

    public function getUid()
    {
        return $this->uid;
    }
}

　　

2.收款方

class UserPayee extends User
{
    public function changeMoney($money)
    {
        $this->money += $money;

        // 写入明细
        $this->mediator->writeMoneyDetail([
            'uid'   => $this->uid,
            'money' => $money,
            'rule'  => '+'
        ]);

        $attributes = [
            'to_uid'    => $this->uid,
            'from_uid'  => $this->mediator->getPayerUid(),
            'money'     => $money
        ];
        // 增加通知
        $this->mediator->notify($attributes);
    }
}

　　

四.继续创建同事类:通知类

/**
 * 通知类
 * Class Notify
 */
class Notify extends Colleague
{
    public function writeNotify(array $attribute)
    {
        echo "用户{$attribute['from_uid']}向用户{$attribute['to_uid']}打赏{$attribute['money']}个金币<br>";
    }
}

　　

五.继续创建同事类:金币明细

/**
 * 金币明细
 * Class MoneyDetial
 */
class MoneyDetial extends Colleague
{
    public function writeToDb(array $attribute)
    {
        echo "UID为{$attribute['uid']}的用户金币{$attribute['rule']} {$attribute['money']}<br>";
    }
}

　　

六.中介者类:

/**
 * 中介者类
 * Class Mediator
 */
class Mediator
{
    private $userPayer;
    private $userPayee;
    private $notify;
    private $moneyDetial;

    public function __construct(UserPayer $userPayer,
                                UserPayee $userPayee,
                                Notify $notify,
                                MoneyDetial $moneyDetial)
    {
        $this->userPayer    = $userPayer;
        $this->userPayee    = $userPayee;
        $this->notify       = $notify;
        $this->moneyDetial  = $moneyDetial;
    }

    /**
     * 写入明细
     * @param array $arributes
     */
    public function writeMoneyDetail(array $arributes)
    {
        $this->moneyDetial->writeToDb($arributes);
    }

    /**
     * 收款
     * @param $money
     */
    public function payee($money)
    {
        $this->userPayee->changeMoney($money);
    }

    /**
     * 写入通知
     * @param array $attribute
     */
    public function notify(array $attribute)
    {
        $this->notify->writeNotify($attribute);
    }

    /**
     * 获得付款方UID
     * @return mixed
     */
    public function getPayerUid()
    {
        return $this->userPayer->getUid();
    }
}

　　

七.具体调用

// 创建各个同事类
$userPayer      = new UserPayer(1, 100);
$userPayee      = new UserPayee(2, 200);
$notify         = new Notify();
$moneyDetial    = new MoneyDetial();

// 创建中介者
$mediator = new Mediator($userPayer, $userPayee, $notify, $moneyDetial);

// 为每个同时类设置中介者
$userPayer->setMediator($mediator);
$userPayee->setMediator($mediator);
$notify->setMediator($mediator);
$moneyDetial->setMediator($mediator);

// 打赏
$userPayer->changeMoney(10);

　　

八.输出结果:

UID为1的用户金币- 10
UID为2的用户金币+ 10
用户1向用户2打赏10个金币