# 課題置き場(デザインパターン)
## 9-1 Stateパターン
### (1)状態遷移図

### (2)コード

TheDogTest1.java(Clientクラス)

public class TheDogTest1 {
    public static void main(String[] args) {
        Dog pochi = new Dog();
        pochi.print();
        pochi.kenka();
        pochi.print();
        pochi.taberu();
        pochi.print();
        pochi.kenka();
        pochi.print();
        pochi.asobu();
        pochi.print();
        pochi.asobu();
        pochi.print();
    }
}

Dog.java(Contextクラス)

public class Dog {
    private DogState myState;

    public Dog() {
        myState = TanoshiiState.getInstance();
    }

    public void kenka() {
        myState.iraira(this);
    }

    public void asobu() {
        myState.tanoshii(this);
    }

    public void taberu() {
        myState.tabeta(this);
    }

    public void changeState(DogState d) {
        myState = d;
    }

    public void print() {
        System.out.print("現在、わたし(犬)は「");
        System.out.print(myState.toString());
        System.out.println("」です。");
    }
}

DogState.java(Stateクラス)

abstract class DogState {
    public abstract void iraira(Dog yobidashimoto);

    public abstract void tanoshii(Dog yobidashimoto);

    public abstract void tabeta(Dog yobidashimoto);
}

TanoshiiState.java(ConcreteStateクラス)

class TanoshiiState extends DogState {
    private static TanoshiiState s = new TanoshiiState();

    private TanoshiiState() {
    };

    public static DogState getInstance() {
        return s;
    }

    public void iraira(Dog moto) {
        moto.changeState(FutsuuState.getInstance());
    }

    public void tabeta(Dog moto) {
        // なにもしない
    }

    public void tanoshii(Dog moto) {
        // なにもしない
    }

    public String toString() {
        return "楽しい状態";
    }
}

FutsuuState.java(ConcreteStateクラス)

class FutsuuState extends DogState {
    private static FutsuuState s = new FutsuuState();

    private FutsuuState() {
    };

    public static DogState getInstance() {
        return s;
    }

    public void iraira(Dog moto) {
        moto.changeState(IrairaState.getInstance());
    }

    public void tabeta(Dog moto) {
        moto.changeState(NemuiState.getInstance());
    }

    public void tanoshii(Dog moto) {
        moto.changeState(TanoshiiState.getInstance());
    }

    public String toString() {
        return "普通状態";
    }
}

IrairaState.java(ConcreteStateクラス)

class IrairaState extends DogState {
    private static IrairaState s = new IrairaState();

    private IrairaState() {
    };

    public static DogState getInstance() {
        return s;
    }

    public void iraira(Dog moto) {
        // なにもしない
    }

    public void tabeta(Dog moto) {
        moto.changeState(NemuiState.getInstance());
    }

    public void tanoshii(Dog moto) {
        moto.changeState(FutsuuState.getInstance());
    }

    public String toString() {
        return "いらいら状態";
    }
}

NemuiState.java(ConcreteStateクラス)

class NemuiState extends DogState {
    private static NemuiState s = new NemuiState();

    private NemuiState() {
    };

    public static DogState getInstance() {
        return s;
    }

    public void iraira(Dog moto) {
        moto.changeState(IrairaState.getInstance());
    }

    public void tabeta(Dog moto) {
        // なにもしない
    }

    public void tanoshii(Dog moto) {
        moto.changeState(FutsuuState.getInstance());
    }

    public String toString() {
        return "眠い状態";
    }
}

### 実行結果