Java进阶学习（5）之设计原则(下)

框架加数据

• 把数据的硬编码尽可能解成框架加数据的结构
• 城堡游戏修改后的代码
  • 　　Room类

  • package com.castle;
    
    import java.util.HashMap;
    
    public class Room {
        private String description;
        private HashMap<String, Room> exits=new HashMap<String, Room>();
        
    
        public Room(String description) 
        {
            this.description = description;
        }
    
        public String getEixtDesc()
        {
            StringBuffer sb=new StringBuffer();
            for (String dir : exits.keySet())
            {
                sb.append(dir+" ");
            }
            return sb.toString();
        }
        
        public void setExit(String dir,Room room)
        {
            exits.put(dir, room);
        }
        
    
        public Room getExit(String direction)
        {
            return exits.get(direction);
        }
        
        @Override
        public String toString()
        {
            return description;
        }
    }

  • Game类

  • package com.castle;
    
    import java.util.HashMap;
    import java.util.Scanner;
    
    public class Game {
        private Room currentRoom;
            
        private HashMap<String, Handler> handlers=new HashMap<String, Handler>();
        public Game() 
        {
            handlers.put("go", new HandlerGo(this));
            handlers.put("Bye", new HandlerBye(this));
            handlers.put("Help", new HandlerHelp(this));
            createRooms();
        }
    
        private void createRooms()
        {
            Room outside, lobby, pub, study, bedroom;
          
            //    制造房间
            outside = new Room("城堡外");
            lobby = new Room("大堂");
            pub = new Room("小酒吧");
            study = new Room("书房");
            bedroom = new Room("卧室");
            
            //    初始化房间的出口
            outside.setExit("east", lobby) ;
            outside.setExit("south", study) ;
            outside.setExit("west", pub) ;
            
            lobby.setExit("west", outside) ;
            
            pub.setExit("east", outside) ;
            
            study.setExit("north", outside) ;
            study.setExit("east", bedroom) ;
            
            bedroom.setExit("west", study) ;
            
            lobby.setExit("up", pub);
            pub.setExit("down", lobby);
            
           
    
            currentRoom = outside;  //    从城堡门外开始
        }
    
        private void printWelcome() {
            System.out.println();
            System.out.println("欢迎来到城堡！");
            System.out.println("这是一个超级无聊的游戏。");
            System.out.println("如果需要帮助，请输入 'help' 。");
            System.out.println();
            showPrompt();
            
        }
    
        // 以下为用户命令
    
      
    
        public void showPrompt()
        {
            System.out.println("你在" + currentRoom);
            System.out.print("出口有: ");
            System.out.println(currentRoom.getEixtDesc());
            System.out.println();
        }
        
        public void goRoom(String direction) 
        {
            Room nextRoom = currentRoom.getExit(direction);
            
            if (nextRoom == null) {
                System.out.println("那里没有门！");
            }
            else {
                currentRoom = nextRoom;
                showPrompt();
            }
        }
        
        public void play()
        {
            Scanner in = new Scanner(System.in);
            while ( true ) {
                String line = in.nextLine();
                String[] words = line.split(" ");
                Handler handler=handlers.get(words[0]);
                String value="";
                if(words.length>1)
                    value=words[1];
                if(handler !=null) 
                {
                    handler.doCmd(value);
                    if(handler.isBye())
                        break;
                }
    //            if ( words[0].equals("help") ) {
    //                printHelp();
    //            } else if (words[0].equals("go") ) {
    //                goRoom(words[1]);
    //            } else if ( words[0].equals("bye") ) {
    //                break;
    //            }
            }
            in.close();
        }
        
        public static void main(String[] args) {
            Game game = new Game();
            game.printWelcome();
            game.play();
            System.out.println("感谢您的光临。再见！");
        }
    
    }

  • Handler类及其子类

  • package com.castle;
    
    public class Handler
    {
    
        protected Game game;
        
        
        
        public Handler(Game game)
        {
            
            this.game = game;
        }
        public void doCmd(String word) {}
        public boolean isBye() {return false;}
        public static void main(String[] args)
        {
            // TODO Auto-generated method stub
    
        }
    
    }
    
    
    
    package com.castle;
    
    public class HandlerBye extends Handler
    {
    
        public HandlerBye(Game game)
        {
            super(game);
            // TODO Auto-generated constructor stub
        }
    
        @Override
        public boolean isBye()
        {
            // TODO Auto-generated method stub
            return true;
        }
    
    }
    
    
    
    
    package com.castle;
    
    public class HandlerHelp extends Handler
    {
    
        public HandlerHelp(Game game)
        {
            super(game);
            // TODO Auto-generated constructor stub
        }
    
        @Override
        public void doCmd(String word)
        {
            System.out.print("迷路了吗？你可以做的命令有：go bye help");
            System.out.println("如：	go east");
        }
    
    }
    
    
    
    
    package com.castle;
    
    public class HandlerGo extends Handler
    {
    
        public HandlerGo(Game game)
        {
            super(game);
            // TODO Auto-generated constructor stub
        }
    
        @Override
        public void doCmd(String word)
        {
            // TODO Auto-generated method stub
            game.goRoom(word);
        }
    
    }