add new State Pattern example

Author: dslsyeoh

src/com/dsl/design/pattern/state/example3/AddPointState.java

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+/*
+ * Author Steven Yeoh
+ * Copyright (c) 2019. All rights reserved.
+ */
+
+package com.dsl.design.pattern.state.example3;
+
+public class AddPointState extends GameState
+{
+    public AddPointState(MyGame myGame)
+    {
+        super(myGame);
+    }
+
+    @Override
+    public void getPoints()
+    {
+        myGame.setPoints(myGame.points() + 1);
+        System.out.println("Added 1 point");
+    }
+
+    @Override
+    public String getState()
+    {
+        return "Add Point State";
+    }
+}

src/com/dsl/design/pattern/state/example3/GameState.java

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+/*
+ * Author Steven Yeoh
+ * Copyright (c) 2019. All rights reserved.
+ */
+
+package com.dsl.design.pattern.state.example3;
+
+public abstract class GameState
+{
+    MyGame myGame;
+
+    public GameState(MyGame myGame)
+    {
+        this.myGame = myGame;
+    }
+
+    public abstract void getPoints();
+
+    public abstract String getState();
+}

src/com/dsl/design/pattern/state/example3/LosePointState.java

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+/*
+ * Author Steven Yeoh
+ * Copyright (c) 2019. All rights reserved.
+ */
+
+package com.dsl.design.pattern.state.example3;
+
+public class LosePointState extends GameState
+{
+    public LosePointState(MyGame myGame)
+    {
+        super(myGame);
+    }
+
+    @Override
+    public void getPoints()
+    {
+        myGame.setPoints(myGame.points() - 1);
+        System.out.println("Lose 1 point");
+    }
+
+    @Override
+    public String getState()
+    {
+        return "Lose Point State";
+    }
+}

src/com/dsl/design/pattern/state/example3/MyGame.java

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+/*
+ * Author Steven Yeoh
+ * Copyright (c) 2019. All rights reserved.
+ */
+
+package com.dsl.design.pattern.state.example3;
+
+import java.util.stream.IntStream;
+
+public class MyGame
+{
+    private int points;
+
+    private GameState gameState;
+
+    private AddPointState ADD_POINT = new AddPointState(this);
+    private LosePointState LOSE_POINT = new LosePointState(this);
+
+    public MyGame(int points)
+    {
+        this.points = points;
+    }
+
+    public int points()
+    {
+        return points;
+    }
+
+    public void setPoints(int points)
+    {
+        this.points = points;
+    }
+
+    public void test()
+    {
+        gameState = ADD_POINT;
+        IntStream.range(0, 3).forEach(i -> gameState.getPoints());
+        System.out.println(String.format("Current state: %s, point: %d", gameState.getState(), points));
+        gameState = LOSE_POINT;
+        IntStream.range(0, 2).forEach(i -> gameState.getPoints());
+        System.out.println(String.format("Current state: %s, point: %d", gameState.getState(), points));
+    }
+
+}

src/com/dsl/design/pattern/state/example3/StatePatternDemo.java

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+/*
+ * Author Steven Yeoh
+ * Copyright (c) 2019. All rights reserved.
+ */
+
+package com.dsl.design.pattern.state.example3;
+
+public class StatePatternDemo
+{
+    public static void main(String[] args)
+    {
+        MyGame myGame = new MyGame(0);
+        myGame.test();
+    }
+}