PHP设计模式 - 中介者模式

中介者模式用于开发一个对象，这个对象能够在类似对象相互之间不直接相互的情况下传送或者调解对这些对象的集合的修改。 一般处理具有类似属性，需要保持同步的非耦合对象时，最佳的做法就是中介者模式。PHP中不是特别常用的设计模式。

<?php
abstract class Mediator { // 中介者角色
    abstract public function send($message,$colleague);
} 

abstract class Colleague { // 抽象对象
    private $_mediator = null;
    public function __construct($mediator) {
        $this->_mediator = $mediator;
    }
    public function send($message) {
        $this->_mediator->send($message,$this);
    }
    abstract public function notify($message);
} 

class ConcreteMediator extends Mediator { // 具体中介者角色
    private $_colleague1 = null;
    private $_colleague2 = null;
    public function send($message,$colleague) {
        //echo $colleague->notify($message);
        if($colleague == $this->_colleague1) {
            $this->_colleague1->notify($message);
        } else {
            $this->_colleague2->notify($message);
        }
    }
    public function set($colleague1,$colleague2) {
        $this->_colleague1 = $colleague1;
        $this->_colleague2 = $colleague2;
    }
} 

class Colleague1 extends Colleague { // 具体对象角色
    public function notify($message) {
        echo 'colleague1：'.$message."<br>";
    }
} 

class Colleague2 extends Colleague { // 具体对象角色
    public function notify($message) {
        echo 'colleague2：'.$message."<br>";
    }
} 

// client
$objMediator = new ConcreteMediator();
$objC1 = new Colleague1($objMediator);
$objC2 = new Colleague2($objMediator);
$objMediator->set($objC1,$objC2);
$objC1->send("to c2 from c1"); //输出：colleague1：to c2 from c1
$objC2->send("to c1 from c2"); //输出：colleague2：to c1 from c2