public class RemoteController {
  // 开 按钮的命令数组
  Command[] onCommands;
  Command[] offCommands;
  // 执行撤销的命令
  Command undoCommand;
  // 构造器，完成对按钮初始化
  public RemoteController() {
  onCommands = new Command[5];
  offCommands = new Command[5];
  for (int i = 0; i < 5; i++) {
    onCommands[i] = new NoCommand();
    offCommands[i] = new NoCommand();
  }
  }
  // 给我们的按钮设置你需要的命令
  public void setCommand(int no, Command onCommand, Command offCommand) {
  onCommands[no] = onCommand;
  offCommands[no] = offCommand;
  }
  // 按下开按钮
  public void onButtonWasPushed(int no) { // no 0
  // 找到你按下的开的按钮， 并调用对应方法
  onCommands[no].execute();
  // 记录这次的操作，用于撤销
  undoCommand = onCommands[no];
  }
  // 按下关按钮
  public void offButtonWasPushed(int no) { // no 0
  // 找到你按下的关的按钮， 并调用对应方法
  offCommands[no].execute();
  // 记录这次的操作，用于撤销
  undoCommand = offCommands[no];
  }
  // 按下撤销按钮
  public void undoButtonWasPushed() {
  undoCommand.undo();
  }
}

public class Client {
  public static void main(String[] args) {
  // TODO Auto-generated method stub
  //使用命令设计模式，完成通过遥控器，对电灯的操作
  //创建电灯的对象(接受者)
  LightReceiver lightReceiver = new LightReceiver();
  //创建电灯相关的开关命令
  LightOnCommand lightOnCommand = new LightOnCommand(lightReceiver);
  LightOffCommand lightOffCommand = new LightOffCommand(lightReceiver);
  //需要一个遥控器
  RemoteController remoteController = new RemoteController();
  //给我们的遥控器设置命令, 比如 no = 0 是电灯的开和关的操作
  remoteController.setCommand(0, lightOnCommand, lightOffCommand);
  System.out.println("--------按下灯的开按钮-----------");
  remoteController.onButtonWasPushed(0);
  System.out.println("--------按下灯的关按钮-----------");
  remoteController.offButtonWasPushed(0);
  System.out.println("--------按下撤销按钮-----------");
  remoteController.undoButtonWasPushed();
  System.out.println("=========使用遥控器操作电视机==========");
  TVReceiver tvReceiver = new TVReceiver();
  TVOffCommand tvOffCommand = new TVOffCommand(tvReceiver);
  TVOnCommand tvOnCommand = new TVOnCommand(tvReceiver);
  //给我们的遥控器设置命令, 比如 no = 1 是电视机的开和关的操作
  remoteController.setCommand(1, tvOnCommand, tvOffCommand);
  System.out.println("--------按下电视机的开按钮-----------");
  remoteController.onButtonWasPushed(1);
  System.out.println("--------按下电视机的关按钮-----------");
  remoteController.offButtonWasPushed(1);
  System.out.println("--------按下撤销按钮-----------");
  remoteController.undoButtonWasPushed();
  }
}