MOOC:面向对象程序设计——java语言 第五节拓展

为什么有这篇文章

面向对象设计思想是现代程序设计的重要基础，目前我在MOOC上学习翁凯老师的java进阶，主要就是进行面向对象的入门学习。

在课程中，第五节讲述了了面向对象简单实际应用，主要例子是城堡游戏，将其降提供的原始低耦合，使用类的继承提高程序的拓展性。

编程的学习中，实际的练习十分重要，以前总是看视频进行学习，觉得十分简单，但实际操作时依然困难重重。

所以我就这个 城堡游戏 的课后讨论中提出的 随机进入房间 进行了实现，并将结果做一个备份。

MOOC地址

面向对象程序设计——Java语言
实践来源是其课后讨论中的

如何实现任意门？

如果想要实现任意门，即在某个房间，想要从某个出口出去，结果每次会走到不同的房间去。
如果要实现这样的任意门，整个程序的架构应该是怎样的？
如果任意门只是在这个房间的所有的门之间轮转，应该怎样实现？
如果任意门能在整个城堡的所有的门之间轮转，应该怎样实现？
来自课件“如何实现任意门？”

代码部分

话不多说直接放代码，代码均添加了详细的以下文件均在一个名为castle的package中。

• 首先是Game.java

package castle;

/*
 * 20181014 by Dreamer
 */
import java.util.HashMap;
import java.util.Scanner;

public class Game {
    private Room currentRoom;// 当前房间

    // 操作String与对应handler的HashMap
    // Room名字String与对应Room的HashMap
    private HashMap<String, Handler> handlers = new HashMap<String, Handler>();
    private HashMap<String, Room> rooms = new HashMap<String, Room>();

    // 初始化
    public Game() {
        createRooms();
        currentRoom = rooms.get("outside"); // 从城堡门外开始
        handlers.put("go", new HandlerGo(this));
        handlers.put("bye", new HandlerBye(this));
        handlers.put("help", new HandlerHelp(this));
        handlers.put("random", new HandlerGoRandom(this));
        handlers.put("randomRoom", new HandlerRandomRoom(this));
    }

    // 制造及设置Room的HashMap
    private void createRooms() {

        // 制造Room
        rooms.put("outside", new Room("城堡外"));
        rooms.put("lobby", new Room("大堂"));
        rooms.put("pub", new Room("小酒吧"));
        rooms.put("study", new Room("书房"));
        rooms.put("bedroom", new Room("卧室"));
        rooms.put("heiwu", new Room("小黑屋"));

        // 初始化Room的出口
        addRoom("outside", "south", "lobby");
        addRoom("outside", "east", "study");
        addRoom("outside", "west", "pub");
        addRoom("lobby", "north", "outside");
        addRoom("pub", "east", "outside");
        addRoom("study", "west", "outside");
        addRoom("study", "south", "bedroom");
        addRoom("bedroom", "north", "study");
        addRoom("bedroom", "up", "heiwu");
        addRoom("heiwu", "down", "bedroom");
    }

//    设置Room出口的方法
    private void addRoom(String room, String direction, String nextRoom) {
        rooms.get(room).setExit(direction, rooms.get(nextRoom));
    }

//    欢迎
    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();
        System.out.println("现在你在" + currentRoom);
        System.out.print("出口有：");
        System.out.println(currentRoom.getExitDesc());

    }

//    返回Room的数量
    public int getSize() {
        int size = 0;
        size = rooms.size();
        return size;
    }

//    接受Room的名字String
//    返回对应的Room
    public Room getRoom(String roomKey) {
        return rooms.get(roomKey);
    }

//    返回当前所在的Room
    public Room getRoomNow() {
        return currentRoom;
    }

//    返回所有Room名字的String[]
    public String[] getMapKey() {
        String[] mapKeyList = rooms.keySet().toArray(new String[getSize()]);
        return mapKeyList;
    }

//    接受方向String
//    返回对应的Room
    public void goRoom(String direction) {
        Room nextRoom = null;
        nextRoom = currentRoom.goRoom(direction);

        if (nextRoom == null) {
            System.out.println("那里没有门！");
        } else {
            currentRoom = nextRoom;
            System.out.println("你在" + currentRoom);
            System.out.print("出口有：");
            System.out.println(currentRoom.getExitDesc());
        }
    }

//    接受一个Room
//    将此Room设为当前Room
    public void resetRoom(Room room) {
        currentRoom = room;
        System.out.println("你在" + currentRoom);
        System.out.print("出口有：");
        System.out.println(currentRoom.getExitDesc());
    }

//    运行游戏
    public void play() {
        Scanner in = new Scanner(System.in);

        while (true) {
            String line = in.nextLine();// 读取输入
            String[] words = line.split(" ");// 以“ ”为分隔转为String[]
            Handler handler = handlers.get(words[0]);// 第0个string是操作
            String value = words[0];// 默认value设为第0个string

            // 如果有不止一个输入，则将value设为第1个string作为参数
            if (words.length > 1) {
                value = words[1];
            }
            // 如果有这个操作的话就把参数传入做handler.doCmd(value)
            if (handler != null) {
                handler.doCmd(value);
                if (handler.isBye()) {
                    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！");

    }

}

• Room.java

package castle;

/*
 * 20181014 by Dreamer
 */
import java.util.HashMap;

public class Room {
    private String description;// 房间描述

    // 出口String及对应Room的HashMap
    private HashMap<String, Room> room = new HashMap<String, Room>();

    // 初始化，给房间描述
    public Room(String getdescription) {
        description = getdescription;
    }

    // 设置Room的出口String及对应的Room
    public void setExit(String direction, Room nextroom) {
        room.put(direction, nextroom);
    }

    // 返回将出口String加空格
    public String getExitDesc() {
        StringBuffer sb = new StringBuffer();
        for (String a : room.keySet()) {
            sb.append(a + " ");
        }
        return sb.toString();

    }

    // 返回出口string的HashMap大小
    public int getSize() {
        int size = 0;
        size = room.size();
        return size;
    }

    // 返回出口String的list
    public String[] getMapKey() {
        String[] mapKeyList = room.keySet().toArray(new String[getSize()]);
        return mapKeyList;
    }

    // 返回对应String的Room
    public Room goRoom(String direction) {
        return room.get(direction);
    }

    // 重构toString()
    @Override
    public String toString() {
        return description;
    }

}

• HandlerBye.java

package castle;
/*
 * 20181014 by Dreamer
 * 1退出
 */

public class HandlerBye extends Handler {
    public HandlerBye(Game game) {
        super(game);
    }

    // 返回isBye的true
    public boolean isBye() {
        return true;
    }
}

• HandlerGo.java

package castle;
/*
 * 20181014 by Dreamer
 * 1去一个指定的room
 */

public class HandlerGo extends Handler {
    public HandlerGo(Game game) {
        super(game);
    }

    // 接收string去所指的room
    public void doCmd(String word) {
        game.goRoom(word);
    }
}

• HandlerGoRandom.java

package castle;
/*
 * 20181014 by Dreamer
 * 1随机到一个紧邻当前room的room
 */

public class HandlerGoRandom extends Handler {

    public HandlerGoRandom(Game game) {
        super(game);
    }

    public void doCmd(String word) {
        Room room = game.getRoom(word);
        if (room == null) {
            room = game.getRoomNow();
        }

        int num = room.getSize();

        int rand = (int) (Math.random() * num);
        String[] keyMap = room.getMapKey();
        word = keyMap[rand];
        game.goRoom(word);
    }
}

• HandlerHelp.java

package castle;
/*
 * 20181014 by Dreamer
 * 1退出
 */

public class HandlerHelp extends Handler {

    public HandlerHelp(Game game) {
        super(game);
    }

    public void doCmd(String word) {
        System.out.println("迷路了吗？你可以做的命令有：go bye help");
        System.out.println("如：\tgo east");
    }

}

• HandlerRandomRoom.java

package castle;
/*
 * 20181014 by Dreamer
 * 1退出
 */

public class HandlerRandomRoom extends Handler {

    public HandlerRandomRoom(Game game) {
        super(game);
    }

    public void doCmd(String word) {
        String room = game.getRoomNow().toString();// 得到当前Room的描述赋给room

        do {
            int num = game.getSize();// 得到game的Room数量
            int rand = (int) (Math.random() * num);// 在数量内随机一个数
            String[] keyMap = game.getMapKey();// 得到game里所有房间的String[]
            word = keyMap[rand];// 用随机数rand取一个room
            game.resetRoom(game.getRoom(word));
            ;// 把取来的room设为当前room
        } while (room.equals(game.getRoom(word).toString()));// 如果随机完了的room和随机前一样，就重来
    }
}