状态设计模式

Question

我正在尝试实现状态模式，但问题是，我没有更改状态，当我使用测试类时，它使用的是与接口有关系的具体类。

例如，状态类中的 fire 和 move 方法不起作用并返回 Railgun 的结果。

这是代码：

public interface RailgunState 
{

    public String fire(Point p, int rounds);
    public String move(Point p);
}

public class Railgun 
{
    /**
     * @param ammo repersent the current ammonitions.
     */
     int ammo = 0;
     /**
     * @param MAX_AMMO repersent the maximum ammonitions.
     */
      public static int MAX_AMMO = 10;
    int test = 10;
    /**
     *@param position represent the possition of the state 
     */
    Point position;
    Point point;
    //ask mark
    int x = 0;
    int y = 0;
    int result = 6;
    /**
     * @param damagedState represent an object of DamagedState
     */
    RailgunState damagedState ;
    RailgunState needAmmoState ;
    RailgunState normalState ;
     /**
     * @param state represent the state of the RailGun
     */
    RailgunState state; 

    Railgun()
    {
        damagedState = new DamagedState();
        needAmmoState = new NeedAmmoState();
        normalState = new NormalState();
        state = normalState;
    }
    /** fire().
     * @param p is the coordinates of the target
     * @param rounds number of rounds HQ has requested
     * @return success/ partial success/ failure
     */
    public String fire(Point p, int rounds)
    {
         return "Fire order: Success 6/6";
    }

    /**  move(). success or failure only the string
     * @param p is the destination
     * @return success or failure when a railgun can move to the destination
     */
    public String move(Point p)
    {
        position = p;
        return  "Move order: Success" ; 
    }

    /**getPosition().
     * @return the possstion of the point 
     */
    public Point getPosition()
    {             
        return position ;
    }

    void setPosition(Point position)
    {
        this.position = position;
    }

     public RailgunState getState()
    {
        return state;
    }

    void setAmmo(int ammo) 
    {
        this.ammo = ammo;
    }

    public Point getPoint() {
        return point;
    }

    public RailgunState getDamagedState() {
        return damagedState;
    }

    public RailgunState getNeedAmmoState() {
        return needAmmoState;
    }

    public RailgunState getNormalState() {
        return normalState;
    }

    int getAmmo()
    {
        return MAX_AMMO;
    }

    void setState(RailgunState state)
    {
         this.state = state;
    }
    void setState(NeedAmmoState needAmmoState)
    {
        this.state = needAmmoState;
    }

    void setState(NormalState normal)
    {
        this.state = normalState;
    }
        void setState(DamagedState damagedState)
    {
        this.state = damagedState;
    }
}


public class NormalState implements RailgunState {

    Railgun railgun;    
    static int MAX_AMMO = 10;
    int result = 6;

    NormalState()
    {
    }
    @Override
    public String fire(Point p, int rounds) 
    {
        MAX_AMMO -= rounds;
        if((MAX_AMMO >= 0) && (rounds == result))
        {
            NeedAmmoState needAmmo = new NeedAmmoState();
            System.out.println("Seccuees: " + MAX_AMMO);
            NormalState state = new NormalState();
            railgun.setState(state);
            return "Fire order: Success 6/6";
        }
        else if((MAX_AMMO < 0) && (MAX_AMMO != -result))
        {
              System.out.println("Partial: " + MAX_AMMO);
              Railgun.MAX_AMMO = 0;
              System.out.println("Partial: " + MAX_AMMO);
              NeedAmmoState needAmmo = new NeedAmmoState();
              railgun.setState(needAmmo);
              return "Fire order: Partial success 4/6";
        }

        else 
        {
             System.out.println("Fail: " + MAX_AMMO);
             DamagedState damaged = new DamagedState();
             railgun.setState(damaged);
             return "Fire order: Failure 0/6";
        }
    }

    @Override
    public String move(Point p)
    {
        return p + "";
    }

    /**getPosition().
     * @return the possstion of the point 
     */
    public Point getPosition()
    {             
        return railgun.getPosition();
    }
}


public class NeedAmmoState implements RailgunState
{
    Point position;
    Railgun railgun;
    NeedAmmoState()
    {
    }

    @Override
    public String fire(Point p, int rounds)
    {
          return "Fire order: Failed 0/4";
    }

    @Override
    public String move(Point p)
    {
        railgun = new Railgun();
         railgun.move(p);
        position = p;
        return  "Move order: Success" ; 
    }

    void setPosition(Point position)
    {
        this.position = position;
    }
    int getAmmo()
    {
        return Railgun.MAX_AMMO;
    }

    /**getPosition().
     * @return the possstion of the point 
     */
    public Point getPosition()
    {             
        int x = 320;
        int y = 43;
        Point p = new Point(x,y);
        return p;
    }
}


public class NormalStateTest {

    /**
     * Test of fire method, of class NormalState.
     */
    @Test
    public void testFire() {
        final Railgun railgun = new Railgun();
        railgun.setState(new NormalState());
        final int numRounds = 6;
        final int x = 100;
        final int y = 340;

        // This fire mission should be completely successful
        String actualResult = railgun.fire(new Point(x, y), numRounds);
        String expectedResult = "Fire order: Success 6/6";
        //System.out.println(actualResult);
        assertEquals(expectedResult, actualResult);

        // This fire mission should be partially successful
        actualResult = railgun.fire(new Point(x, y), numRounds);
        //System.out.println(actualResult);
        expectedResult = "Fire order: Partial success 4/6";
        assertEquals(expectedResult, actualResult);

        // This fire mission should fail
        actualResult = railgun.fire(new Point(x, y), numRounds);
        //System.out.println(actualResult);
        expectedResult = "Fire order: Failure 0/6";
        assertEquals(expectedResult, actualResult);

        // Check state change to NeedAmmo state
        assertEquals(railgun.getState().getClass(), NeedAmmoState.class); 
    }

    /**
     * Test of move method, of class NormalState. Should always succeed.
     */
    @Test
    public void testMove() {
        final Railgun railgun = new Railgun();
        final int x = 129;
        final int y = 444;
        final String actualResult = railgun.move(new Point(x, y));
        final String expectedResult = "Move order: Success";
        System.out.println(actualResult);
        assertEquals(new Point(x, y), railgun.getPosition());
        assertEquals(expectedResult, actualResult);
    }
}

所以问题是，例如在 NormalStateTest.java 中进行测试时，NormalState 和 NeedAmmoSate 等类的结果在方法 fire 和 move 中返回来自 Railgun 的值。

Answer 1

如果您希望RailGun.fire()方法委托给当前状态的fire()方法，请执行此操作。 在您的代码中，它返回一个硬编码的字符串并且根本不使用状态。

改变

public String fire(Point p, int rounds) {
     return "Fire order: Success 6/6";
}

到

public String fire(Point p, int rounds) {
     return state.fire(p, rounds);
}