2

I'm a programing student.

I've been having problem to organize Java classes that use inheritance and static final variables.

Let say I have an abstract class named Form that has two children named Rectangle and Triangle. Those two children have a final static variable named NumberOfSides.

Both children classes need identical getters for that variable....

Would it be possible to write that getter in the "mother" class?

Thanks for your help.

3

This should not be a constant (aka static final).

Given an instance of 'form' (you don't know what class it is), you can call a method 'getNumberOfSides' that will give you what you want. That's a standard method.

You could also consider a factory: FormFactory.createNewFormWithNumberOfSides(n).

Now, you could have something like:

class Triangle implements Form {
  public final static int TRIANGLE_SIDES = 3;

  @Override
  public int getNumberOfSides(){
    return TRIANGLE_SIDES;
  }
}

But avoiding constants (statics) within a hierarchy that shadow each other is a good idea.

  • Thanks for your response! I will check the FormFactory thing :) But it seems to have to do with swing.. Anyway, I would prefer not using constant then, so I won't have to override a simple getter in all the children of a mother Class. – leseulsteve Feb 7 '14 at 13:42
  • The factory pattern (en.wikipedia.org/wiki/Factory_method_pattern) isn't swing specific. – ptyx Feb 7 '14 at 17:14

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