设计模式6.1-命令模式

<?php

/*
*
*   命令模式：将请求封装，并把发出请求的对象和处理请求的对象解耦，并支持撤销请求的操作。
*
*   关键元素：客户，调用者，请求，接收者。
*
*   在我们的示例中，客户对应Test类，调用者对应Console(控制台)，命令对应Command接口的具体实现类，接收者对应Light(灯)和Fan(电风扇)。
*
*   我们在使用时，即在客户类Test中使用时，如果多添加一个接收者，我们只需要添加一个Command和接收者，在setCommand时绑定。不用修改调用者的代码。
*   同时，命令模式还支持宏命令和撤销操作，在示例中我们仅提供了宏命令的实现MacroCommand。
*/

interface Command
{
    public function execute();
}

class LightOnCommand implements Command
{
    private $light;

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

    public function execute()
    {
        $this->light->LightOn();
    }
}
class LightOffCommand implements Command
{
    private $light;

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

    public function execute()
    {
        $this->light->LightOff();
    }
}

class FanOnConmmand implements Command
{
    private $fan;

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

    public function execute()
    {
        $this->fan->FanOn();
    }
}

class FanOffCommand implements Command
{
    private $fan;

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

    public function execute()
    {
        $this->fan->FanOff();
    }
}

class MacroCommand implements Command
{
    private $commands;

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

    public function execute()
    {
        foreach ($this->commands as $command) {
            $command->execute();
        }
    }
}


class Light
{
    public function LightOn()
    {
        echo "Light is on<br>\n";
    }

    public function LightOff()
    {
        echo "Light is off<br>\n";
    }
}

class Fan
{
    public function FanOn()
    {
        echo "Fan is on<br>\n";
    }

    public function FanOff()
    {
        echo "Fan is off<br>\n";
    }
}

class Console
{
    private $commands = null;

    public function setCommand($pos, $command)
    {
        $this->commands[$pos] = $command;
    }

    public function run($pos)
    {
        if (isset($this->commands[$pos])) {
            $this->commands[$pos]->execute();
        }
    }
}

class Test
{
    public function run()
    {

        $light = new Light();
        $fan = new Fan();

        $lightOnCommand = new LightOnCommand($light);
        $lightOffCommand = new LightOffCommand($light);

        $fanOnConmmand = new FanOnConmmand($fan);
        $fanOffCommand = new FanOffCommand($fan);

        $macroCommand = new MacroCommand([$lightOnCommand, $lightOffCommand, $fanOnConmmand, $fanOffCommand]);

        $console = new Console();

        $console->setCommand(0, $lightOnCommand);
        $console->setCommand(1, $lightOffCommand);
        $console->setCommand(2, $fanOnConmmand);
        $console->setCommand(3, $fanOffCommand);
        $console->setCommand(4, $macroCommand);

        $console->run(0);
        $console->run(1);
        $console->run(2);
        $console->run(3);
        $console->run(4);
    }
}

$test = new Test();
$test->run();