常用设计模式——命令模式

/**
 * SimpleRemoteControlTest是命令模式的客户client
 * @author huangy on 2019-05-25
 */
public class SimpleRemoteControlTest {

    public static void main(String[] args) {

        // 遥控器就是调用者
        SimpleRemoteControl simpleRemoteControl = new SimpleRemoteControl();

        Light ligh = new Light();
        LightOnCommand lightOnCommand = new LightOnCommand(ligh);

        // 把命令传递给调用者
        simpleRemoteControl.setSlot(lightOnCommand);

        // 模拟按下按钮
        simpleRemoteControl.buttonWasPressed();
    }


}

/**
 * 简单遥控器
 * @author huangy on 2019-05-25
 */
public class SimpleRemoteControl {

    // 插槽
    Command slot;

    // 把命令对象设置到插槽上面
    public void setSlot(Command slot) {
        this.slot = slot;
    }

    public void buttonWasPressed() {
        slot.execute();
    }
}

/**
 * 所有命令对象的通用接口
 * @author huangy on 2019-05-25
 */
public interface Command {

    /**
     * 执行命令
     */
    void execute();

}

/**
 * @author huangy on 2019-05-25
 */
public class LightOnCommand implements Command {

    public LightOnCommand(Light light) {
        this.light = light;
    }

    /**
     * 电灯
     * 动作的接收者
     */
    private Light light;

    @Override
    public void execute() {
        light.on();
    }
}

/**
 * 电灯
 * @author huangy on 2019-05-25
 */
public class Light {

    public void on() {
        System.out.println("Light on");
    }

}

/**
 * 宏命令
 * @author huangy on 2019-05-25
 */
public class MacroCommand implements Command {

    Command[] commands;

    Deque<Command> deque;

    public MacroCommand(Command[] commands) {
        this.commands = commands;
        deque = new LinkedList<>();
    }

    @Override
    public void execute() {
        for (Command command : commands) {
            command.execute();
            deque.push(command);
        }
    }

    @Override
    public void undo() {
        while (!deque.isEmpty()) {
            // 利用栈实现撤回
            Command command = deque.pop();
            command.undo();
        }
    }
}