设计模式 中介者模式

介绍

中介者模式是一种行为型设计模式，它通过一个中介者对象来封装一系列对象之间的交互，从而使它们之间的耦合度降低，变得更加灵活。

角色

角色	说明
Mediator	抽象中介者
ConcreteMediator	具体中介者
Colleague	抽象同事类
ConcreteColleague	具体同事类

角色示例

类名	担任角色	说明
Express	抽象中介者	快递
SFExpress	具体中介者	顺丰快递
User	抽象同事类	用户
Sender	具体同事类	寄件人
Receiver	具体同事类	收件人

UML类图

代码

<?php 
abstract class User
{
    protected $name;
    protected $express;

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

    abstract public function sendExpress($receiver,$package);
    abstract public function receiveExpress($sender,$package);

    public function checkExpress(){
        if(!$this->express) exit("未设置快递公司");
    }

    public function setExpress($express){
        $this->express = $express;
    }
}

class Sender extends User
{
    public function sendExpress($receiver,$package)
    {
        $this->checkExpress();
        $this->express->ship($receiver,$package);
        return "我是".$this->name."，寄".$package."给".$receiver->name.PHP_EOL;
    }

    public function receiveExpress($sender,$package)
    {
        return "我是".$this->name."，收到".$sender->name."的".$package.PHP_EOL;
    }
}

class Receiver extends User
{
    public function sendExpress($receiver,$package)
    {
        $this->checkExpress();
        $this->express->ship($receiver,$package);
        return "我是".$this->name."，寄".$package."给".$receiver->name.PHP_EOL;
    }

    public function receiveExpress($sender,$package)
    {
        return "我是".$this->name."，收到".$sender->name."的".$package.PHP_EOL;
    }
}

abstract class Express
{
    abstract public function ship($user,$package);
    abstract public function fillForm($user);
}

class SFExpress extends Express
{
    protected static $nameList;
    function __construct()
    {
        if (!isset(self::$nameList)) {
            self::$nameList = [];
        }
    }

    public function ship($user,$package)
    {
        if(count(self::$nameList) < 2) {
            exit("请核对快递单中的寄件或收件人是否填写");
        }
        return $user->receiveExpress($user, $package);
    }

    public function fillForm($user)
    {
        if (!in_array($user, self::$nameList)) {
            self::$nameList[get_class($user)] = $user;
        }
        $user->setExpress($this);
    }
}

$sender = new Sender("小哀");
$receiver = new Receiver("柯南");

$sfEpress = new SFExpress();
$sfEpress->fillForm($sender);
$sfEpress->fillForm($receiver);

echo $sender->sendExpress($receiver, "APTX-4869的解药");
echo $receiver->sendExpress($sender, "感谢信");

创建 Test.php，内容如上。

执行

$ php Test.php
我是小哀，寄APTX-4869的解药给柯南
我是柯南，寄感谢信给小哀