如何继承静态字段并更改其值? [英] How to inherit static field and change it's value?

问题描述

我正在开发带有参数的静态实用程序类的程序/游戏.

I'm working on program/game where I have static utility class with params.

class ParamsGeneral {
   public static final int H_FACTOR = 100;
   public static int MAX_SCORE = 1000;
   ...
}

然后我需要在某些特定情况下覆盖此值，例如在分数有限的地图上玩.所以我做了以下:

then I need to override this values in some specific cases, for example playing on map with limited score. So I did following:

class ParamsLimited extends ParamsGeneral {
   public static int MAX_SCORE = 500;
   // other params stay same
}

预期用途如下:

class Player {
   ParamsGeneral par;
   public Player() {
      if(onLimitedMap()){
          par = new ParamLimited();
      }
   }

   public boolean isWinner() {
      if(this.score == par.MAX_SCORE) {
          return true;
      }
      return false;
   }
}

我还没有真正测试过这段代码，因为 IDE 抱怨通过实例调用静态字段以及字段隐藏.我清楚地看到这段代码很臭，那么有没有办法实现这一点，或者我必须单独编写每个param类?

I haven't actually tested this code, because IDE is complaining about calling static field through instance and also about field hiding. I clearly see that this code is stinks, so is there a way to achieve this or do I have to write each param class separately?

PS:我知道我应该使默认类抽象并使用 getter，我只是想知道是否有办法使这些值静态访问.

PS: I know I shoud make the default class abstract and use getters, I'm just curious if there is a way to make the values accesible statically.

推荐答案

您不能覆盖静态成员 - 在 Java 中，方法和字段都不能被覆盖.但是，在这种情况下，您似乎不需要执行任何操作:由于您在 par 变量中有一个 ParamsGeneral 实例，因此非静态方法将使用常规覆盖执行您需要的操作.

You cannot override static members - in Java, neither methods nor fields could be overriden. However, in this case it does not look like you need to do any of that: since you have an instance of ParamsGeneral in the par variable, a non-static method would do what you need with the regular override.

class ParamsGeneral {
    public int getMaxScore() {
        return 1000;
    }
}
class ParamsLimited extends ParamsGeneral {
    @Override public int getMaxScore() {
        return 500;
    }
}

...

public boolean isWinner() {
    // You do not need an "if" statement, because
    // the == operator already gives you a boolean:
    return this.score == par.getMaxScore();
}

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