<?php
// 命令模式

interface Command
{
	public function execute();
}

/**
 * concrete command, 具体的命令
 */
class ConcreteCommand implements Command
{
	private $receiver;

	public function construct(Receiver $r) {
		$this->receiver = $r;
	}

	public function execute() {
		$this->receiver->doAction();
	}
}

/**
 * 接收者, 命令的执行者
 */
class Receiver
{
	public function doAction() {
		echo 'Action has been taken!<br/>';
	}
}

/**
 * 请求者, 命令的请求者
 */
class Invoker
{
	private $cmd;

	public function construct(Command $cmd) {
		$this->cmd = $cmd;
	}

	/**
	 * call command execute
	 */
	public function action() {
		$this->cmd->execute();
	}
}

// test code
$r = new Receiver();
$cmd = new ConcreteCommand($r);

$invoker = new Invoker($cmd);
$invoker->action();