面向對象程序設計-java語言第七週學習——內部類(匿名函數)

城堡的Handler類
在第5周的城堡程序那裏，我們做的Handler是需要在構造的時候注入Game的。那麼，在學習了內部類之後，能否用Game的內部類來實現這些Handler呢？應該怎麼做？

方法：Handler爲接口，在Game.java構造函數裏用匿名類完成go,bye,help功能

Game.java

package castle;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;

public class Game {
	private Room currentRoom;
	private HashMap<String, Handler> handlers = new HashMap<String, Handler>();
	protected ArrayList<String> cmds = new ArrayList<String>();

	public Game() {
		handlers.put("bye", new Handler() {
			@Override
			public void doCmd(String word) {

			}

			@Override
			public boolean isBye() {
				return true;
			}
		});
		handlers.put("help", new Handler() {
			@Override
			public void doCmd(String word) {
				System.out.println("迷路了嗎？你可以做的命令有：" + cmds);

				System.out.println("如：\tgo east");
			}

			@Override
			public boolean isBye() {
				return false;
			}
		});
		handlers.put("go", new Handler() {
			@Override
			public void doCmd(String word) {
				goRoom(word);
			}

			@Override
			public boolean isBye() {
				return false;
			}
		});
		for (String cmd : handlers.keySet()) {
			cmds.add(cmd);
		}

		createRooms();

	}

	private void createRooms() {
		Room outside, lobby, pub, study, bedroom, inside, bedroomup;

		// 製造房間

		outside = new Room("城堡外");
		inside = new Room("城堡內");
		lobby = new Room("大堂");
		pub = new Room("小酒吧");
		study = new Room("書房");
		bedroom = new Room("臥室");
		bedroomup = new Room("臥室二樓");
//        hoteldown = new Room("賓館一樓");
//        hotelup = new Room("賓館二樓");
		// 設置房間故事
		outside.setNarration("城堡外", "恭喜你逃出了城堡");
		inside.setNarration("城堡內", "你現在在城堡的一個恐怖黑暗的廣場上");
		lobby.setNarration("大堂", "你來到了城堡的大堂，大堂裏面有着恐怖的石像");
		pub.setNarration("小酒吧", "這是一間幽深的酒吧，傍邊到處是黑色的酒瓶，還有這恐怖的音樂在播放着");
		study.setNarration("書房", "這是城堡的書房，裏面記載着這個城堡的過去");
		bedroom.setNarration("臥室", "你來到了城堡主人的臥室，這裏是最黑暗的地方，你的心跳跳的越來越快，快點離開這裏吧！");
		bedroomup.setNarration("臥室二樓", "恭喜你來到了城堡主人的臥室二樓，並且發現了一個箱子，你打開箱子後找到了鑰匙，請拿着鑰匙快速逃出城堡吧！");

		// 初始化房間的出口
		outside.setExit("south", inside);
		inside.setExit("north", outside);
		inside.setExit("east", lobby);
		inside.setExit("south", study);
		inside.setExit("west", pub);
		lobby.setExit("west", inside);
		pub.setExit("east", inside);
		study.setExit("north", inside);
		study.setExit("east", bedroom);
		bedroom.setExit("west", study);
		bedroom.setExit("up", bedroomup);
		bedroomup.setExit("down", bedroom);

		currentRoom = inside; // 從城堡門外開始
	}

	private void printWelcome() {
		System.out.println();
		System.out.println("歡迎來到城堡！");
		System.out.println("這是一個超級無聊的遊戲。任務：你需要在城堡內找到寶箱鑰匙並帶到城堡外去。");
		System.out.println("如果需要幫助，請輸入 'help' 。");
		System.out.println();
		showPrompt();
	}

	// 以下爲用戶命令

	public void goRoom(String direction) {
		Room nextRoom = currentRoom.getExit(direction);

		if (nextRoom == null) {
			System.out.println("那裏沒有門！");
		} else {
			currentRoom = nextRoom;
			showPrompt();
		}
	}

	public void showPrompt() {
		String currentnarration = currentRoom.getNarration(currentRoom.toString());
		System.out.println("你在" + currentRoom + "\n場景描述：" + currentnarration);
		System.out.print("出口有: ");
		System.out.print(currentRoom.getExitDesc());
		System.out.println();
	}

	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;
				}
			}
		}
		in.close();
	}

	public static void main(String[] args) {
		Game game = new Game();
		game.printWelcome();
		game.play();
		System.out.println("感謝您的光臨。再見！");
	}

}

Handler.java

package castle;

public class Handler {
	public void doCmd(String word) {
	}

	public boolean isBye() {
		return false;
	}
}

Room.java

package castle;

import java.util.HashMap;

public class Room {
    private String description;
    private HashMap<String, Room> exits = new HashMap<String, Room>();
    private HashMap<String, String> narration = new HashMap<String, String>();
    
    public Room(String description) 
    {
        this.description = description;
    }
    public void setExit(String dir, Room room) {
    	exits.put(dir, room);
    }
    public void setNarration(String room, String narr) {
    	narration.put(room, narr);
    }
    @Override
    public String toString()
    {	
        return description;
    }
    public String getExitDesc() {
    	StringBuffer sb = new StringBuffer();
    	for (String dir : exits.keySet()) {
    		sb.append(dir);
    		sb.append(' ');
    	}
    		return sb.toString();
    }
    public Room getExit(String direction) {
    	return exits.get(direction);
    }
    public String getNarration(String direction) {
    	return narration.get(direction);
    }
}