class Invoker
{
 public $command;
 
 public function __construct($command)
 {
  $this->command = $command;
 }

 public function exec()
 {
  $this->command->execute();
 }
}

abstract class Command
{
 protected $receiver;

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

 abstract public function execute();
}

class ConcreteCommand extends Command
{
 public function execute()
 {
  $this->receiver->action();
 }
}

class Receiver
{
 public $name;

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

 public function action()
 {
  echo $this->name . '命令执行了！', PHP_EOL;
 }
}

// 准备执行者
$receiverA = new Receiver('A');

// 准备命令
$command = new ConcreteCommand($receiverA);

// 请求者
$invoker = new Invoker($command);
$invoker->exec();

<"external nofollow" target="_blank" href="https://github.com/zhangyue0503/designpatterns-php/blob/master/09.command/source/command-up.php">https://github.com/zhangyue0503/designpatterns-php/blob/master/09.command/source/command-up.php

实例


短信功能又回来了，我们发现除了工厂模式外，命令模式貌似也是一种不错的实现方式哦。在这里，我们依然是使用那几个短信和推送的接口，话不多说，我们用命令模式再来实现一个吧。当然，有兴趣的朋友可以接着实现我们的短信撤回功能哈，想想上面的命令取消是怎么实现的。
短信发送类图

完整源码： https://github.com/zhangyue0503/designpatterns-php/blob/master/09.command/source/command-message.php


<?php

class SendMsg
{
 private $command = [];

 public function setCommand(Command $command)
 {
  $this->command[] = $command;
 }
 
 public function send($msg)
 {
  foreach ($this->command as $command) {
   $command->execute($msg);
  }
 }
}

abstract class Command
{
 protected $receiver = [];

 public function setReceiver($receiver)
 {
  $this->receiver[] = $receiver;
 }

 abstract public function execute($msg);
}

class SendAliYun extends Command
{
 public function execute($msg)
 {
  foreach ($this->receiver as $receiver) {
   $receiver->action($msg);
  }
 }
}

class SendJiGuang extends Command
{
 public function execute($msg)
 {
  foreach ($this->receiver as $receiver) {
   $receiver->action($msg);
  }
 }
}

class SendAliYunMsg
{
 public function action($msg)
 {
  echo '【阿X云短信】发送：' . $msg, PHP_EOL;
 }
}

class SendAliYunPush
{
 public function action($msg)
 {
  echo '【阿X云推送】发送：' . $msg, PHP_EOL;
 }
}

class SendJiGuangMsg
{
 public function action($msg)
 {
  echo '【极X短信】发送：' . $msg, PHP_EOL;
 }
}

class SendJiGuangPush
{
 public function action($msg)
 {
  echo '【极X推送】发送：' . $msg, PHP_EOL;
 }
}

$aliMsg = new SendAliYunMsg();
$aliPush = new SendAliYunPush();
$jgMsg = new SendJiGuangMsg();
$jgPush = new SendJiGuangPush();

$sendAliYun = new SendAliYun();
$sendAliYun->setReceiver($aliMsg);
$sendAliYun->setReceiver($aliPush);

$sendJiGuang = new SendJiGuang();
$sendAliYun->setReceiver($jgMsg);
$sendAliYun->setReceiver($jgPush);

$sendMsg = new SendMsg();
$sendMsg->setCommand($sendAliYun);
$sendMsg->setCommand($sendJiGuang);

$sendMsg->send('这次要搞个大活动，快来注册吧！！');




说明

  
在这个例子中，依然是多命令多执行者的模式
  
可以将这个例子与抽象工厂进行对比，同样的功能使用不同的设计模式来实现，但是要注意的是，抽象工厂更多的是为了生产对象返回对象，而命令模式则是一种行为的选择
  
我们可以看出命令模式非常适合形成命令队列，多命令让命令可以一条一条执行下去
  
它允许接收的一方决定是否要否决请求，Receiver做为实现者拥有更多的话语权