package com.tomkk.dp;

import java.util.ArrayList;
import java.util.List;
import java.util.Stack;

abstract class {
    abstract void excecute();

    abstract void unDo();
}

class ShoppingCmd extends  {

    
    void excecute() {
        System.out.println("陪着逛商场。。。");
    }

    
    void unDo() {
        System.out.println("回家啦~~");
    }
}

class Boy{
    private List<Command> commondList = new ArrayList<>();
    private Stack<Command> commandHistory = new Stack<>();

    public void addCommand(Command command) {
        commondList.add(command);
    }

    public void doCommands() {
        for (Command c : commondList) {
            c.excecute();
          
            commandHistory.push(c);
        }
    }

    public void unDo() {
        if (!commandHistory.empty()) {
            commandHistory.peek().unDo();
            commandHistory.pop();
        }
    }
}

class MM{
    
    public void order(Boy boy) {
        Command cmd = new ShoppingCmd();
        boy.addCommand(cmd);
      
        boy.doCommands();
    }

    public void regret(Boy boy) {
        boy.unDo();
    }

}

public class Main {

    public static void main(String[] args) {
        MM mm = new MM();
        Boy boy = new Boy();

        mm.order(boy);
        mm.regret(boy);
    }
    
}