Can I have different copies of a static variable for each different type of inheriting class

Question

I want to have the same static variable with a different value depending on the type of class.

So I would have

public class Entity
{
     public stat         


        

Answer 1

Use an abstract method:

public class Entity
{
     public abstract Bitmap getSprite();

     public void draw(Canvas canvas, int x, int y)
     {
          canvas.drawBitmap(getSprite(), x, y, null);
     }
}

public class Marine extends Entity
{
    public Bitmap getSprite() {
        return /*the sprite*/;
    }
}

The sprite returned by getSprite can be a static if you like. Nice things about this approach:

• You can't (easily) forget to include a sprite in your subclass, since the compiler will complain if you don't implement the abstract method.

• It's flexible. Suppose a Marine should look different once he "levels up". Just change Marine's getSprite method to take the level into account.

• It's the standard OO-idiom for this sort of thing, so people looking at their code won't be left scratching their heads.