じゃんけん

Janken.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.Normalizer;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import static Janken.Utility.*;

public class Janken {

	static enum Hand {
		Rock("グー"),
		Paper("パー"),
		Scissors("チョキ");

		private final String desc;
		Hand(String desc) {
			this.desc = desc;
		}

		@Override
		public String toString() {
			return this.desc;
		}
		public static Hand of(String code){
			switch (code){
				case "1":
					return Rock;
				case "2":
					return Scissors;
				case "3":
					return Paper;
				default:
					throw new IllegalArgumentException();
			}
		}
	}

	static enum Result {
		IWin("わたしの勝ち！"),
		YouWin("あなたの勝ち！"),
		Draw("あいこ！");

		private final String desc;
		Result(String desc) {
			this.desc = desc;
		}

		@Override
		public String toString() {
			return this.desc;
		}
	}

	static class HandPair {
		private final Hand myHand;
		private final Hand yoursHand;
		public HandPair(Hand myHand, Hand yoursHand) {
			this.myHand = myHand;
			this.yoursHand = yoursHand;
		}

		@Override
		public boolean equals(Object o) {
			if (this == o) return true;
			if (o == null || getClass() != o.getClass()) return false;
			HandPair handPair = (HandPair) o;
			return myHand == handPair.myHand && yoursHand == handPair.yoursHand;
		}

		@Override
		public int hashCode() {
			int result = myHand.hashCode();
			result = 31 * result + yoursHand.hashCode();
			return result;
		}
	}

	static class Judge {
		private final static Map<HandPair, Result> resultMap = new HashMap<HandPair, Result>(){{
			put(new HandPair(Hand.Rock    , Hand.Scissors), Result.IWin);
			put(new HandPair(Hand.Paper   , Hand.Rock)    , Result.IWin);
			put(new HandPair(Hand.Scissors, Hand.Paper)   , Result.IWin);
			put(new HandPair(Hand.Rock    , Hand.Paper)   , Result.YouWin);
			put(new HandPair(Hand.Paper   , Hand.Scissors), Result.YouWin);
			put(new HandPair(Hand.Scissors, Hand.Rock)    , Result.YouWin);
		}};

		public Result judge(Hand myHand, Hand yourHand){
			if(myHand == yourHand){
				return Result.Draw;
			}else{
				return resultMap.get(new HandPair(myHand, yourHand));
			}
		}
	}

	static class Service {

		private final Judge judge;
		private final Random random;
		private int yourWins;
		private int yourRoses;

		public Service() {
			this.judge = new Judge();
			this.random = new Random();
			this.yourWins = 0;
			this.yourRoses = 0;
		}

		public void battle() throws IOException {

			println("じゃんけんするよ！何出す？？");
			HandPair hands = getHands();

			Result result;
			while((result = judge.judge(hands.myHand, hands.yoursHand)) == Result.Draw){
				println(String.format("あなたは%s、わたしも%s。%sもう1回！", hands.yoursHand, hands.myHand, result));
				hands = getHands();
			}
			println(String.format("あなたは%sで、わたしは%s。%s", hands.yoursHand, hands.myHand, result));

			applyResult(result);
			println(String.format("いま、%d勝%d敗だよ！", yourWins, yourRoses));
		}

		private HandPair getHands() throws IOException {
			return new HandPair(decideMyHand(), readYourHand());
		}

		private void applyResult(Result result){
			if(result == Result.IWin){
				yourRoses++;
			}else{
				yourWins++;
			}
		}

		private Hand decideMyHand() {
			return Hand.values()[random.nextInt(3)];
		}

		private Hand readYourHand() throws IOException {
			println("1 グー");
			println("2 チョキ");
			println("3 パー");
			print("1〜3の数字を打ち込んでEnter押してね！⇛");
			String input = readLineFromConsole();
			try {
				return Hand.of(Normalizer.normalize(input, Normalizer.Form.NFKD));
			}catch(IllegalArgumentException e){
				throw new IOException(String.format("入力エラー！[%s]", input));
			}
		}

		public static boolean isContinue() throws IOException {
			println("もう1回？");
			println("続けるなら何か入力してEnterを押してね！やめるならEnterのみ押してね！");
			String input = readLineFromConsole();
			return !input.isEmpty();
		}
	}

	static class Utility {
		private Utility(){}

		public static void print(String str){
			System.out.print(str);
		}
		public static void println(String str){
			System.out.println(str);
		}
		public static void printNl(){
			System.out.println();
		}
		public static void printlnErr(String str){
			System.err.println(str);
		}
		public static String readLineFromConsole() throws IOException {
			return new BufferedReader(new InputStreamReader(System.in)).readLine().trim();
		}
	}


	public static void main(String... args) {

		Service service = new Service();
		while(true){
			try{
				service.battle();

				printNl();
				if(Service.isContinue()){
					println("よし、もう1回〜");
				}else{
					println("おしまい。またね。");
					break;
				}
			}catch (IOException e){
				printNl();
				printlnErr(e.getLocalizedMessage());
			}catch (Exception e){
				e.printStackTrace();
				System.exit(1);
			}
		}
		System.exit(0);
	}
}