java - 查询行为改变对设计的影响——OOP范式

Question

我有一个下面的抽象类 Critter，

/* Critter.java */

/**
 * The abstract class Critter defines a base class for anything(which can be empty)
 * that can exist at a specific location in the ocean.
 * @author mohet01
 *
 */
public  abstract class Critter  {

    /**
     * Below data member defines a location of a Critter in an Ocean
     */

    Point location;


    public Critter(int x, int y){
        location = new Point(x,y);
    }

    public Point getLocation(){
        return location;
    }

    /**
     * This method computes the new value of location(which can be EMPTY) property of Critter.
     * No operation is performed as this is a base class.
     */
    public abstract Critter update(Ocean currentTimeStepSea);


}

---

目前继承了3个子类，分别是Shark类、Fish类和Empty类

---

/* Empty.java */

/**
 * The Empty class defines itself as an entity as it has some meaning/significance
 * being empty in an Ocean. Check update() method for more meaning.
 * @author mohet01
 *
 */
public class Empty extends Critter{ ...}

---

/* Shark.java */

/**
 * The Shark class defines behavior of a Shark in an Ocean.
 * @author mohet01
 *
 */
public class Shark extends Critter{ }

---

/* Fish.java */

/**
 * The Fish class defines the behavior of a Fish in an Ocean
 * @author mohet01
 *
 */
public class Fish extends Critter{ }

---

我的问题是:

如果有机会在基于 future 海洋生物子类的 Critter 类中添加新的行为(方法)，您是否认为上述设计是一个缺陷？

如果是，您建议我如何继续？

附加信息:此应用程序的其余类(与当前查询无关)是 Ocean 类、Point 类、SimText 类、Utility 类。

可以在 link 的查询部分看到完整的代码(如果需要)

Answer 1

接口(interface)定义通用的行为，抽象类提供通用的实现。因此，只需创建一个您的小动物实现的 Locatable 接口(interface):

public interface Locatable {
    Point getLocation();
}

当你有新的行为时，只需创建新的接口(interface)来表示你的小动物实现的它们:

public class Fish implements Locatable, Prey {}

public class Shark implements Locatable, Predator {}

public interface Predator {
    void eat(Prey prey); 
}

public interface Prey {
    void hideFrom(Predator predator);
}