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：\tgo 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);
         }
    
     }