/**
 * @Auther: Arsenal
 * @Date: 2020-03-18 22:48
 * @Description: 命令模式
 */
public class CommandDemo {
    public static void main(String[] args) {
        Receiver receiver = new Receiver();
        Command command = new ConcreteCommand(receiver);
        Command[] commands = new Command[1];
        commands[0] = command;
        Command macroCommand = new MacroCommand(commands);
        Invoker invoker = new Invoker(macroCommand);
        invoker.doInvokerAction();
    }
}

/**
 * 命令角色
 */
interface Command {
    void execute();

    void undo();
}

/**
 * 具体命令角色
 */
class ConcreteCommand implements Command {

    // 持有接收者的引用
    private Receiver receiver;

    public ConcreteCommand(Receiver receiver) {
        this.receiver = receiver;
    }

    @Override
    public void execute() {
        receiver.doAction();
    }

    @Override
    public void undo() {
        receiver.unDoAction();
    }
}

/**
 * 具体命令角色
 */
class MacroCommand implements Command {

    Command[] commands;

    public MacroCommand(Command[] commands) {
        this.commands = commands;
    }

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

    @Override
    public void undo() {
        for (Command command : commands) {
            command.undo();
        }
    }
}

/**
 * 被调用者（士兵）
 */
class Receiver {
    //接收者真正执行命令
    public void doAction() {
        System.out.println("doAction");
    }

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

/**
 * 调用者（将军）
 */
class Invoker {
    //持有命令对象的引用，将动作委托给命令对象执行
    private Command command;

    public Invoker(Command command) {
        this.command = command;
    }

    public void doInvokerAction() {
        command.execute();
    }
}