REALbasic: Sharing common code between disparate subclasses

Question

I have two separate classes (A = a subclass of BevelButtom, B = a subclass of PushButton). Both A and B implement a number of identical methods in exactly the same way. Since both subclasses' superclasses are different and since RB doesn't support multiple inheritance, all I can do to tie these methods together is define a class interface, have both subclasses implement the interface, then copy/paste the method bodies in each subclass.

That offends my sensibilities. Is there a way in RB to extract this common logic elsewhere?

Thanks!

Answer 1

Using an interface seems like the right approach, but rather than copying the method bodies to each subclass, I think it makes more sense to create a new class (say CommonButtonStuff) with the common code. Then you can call it in the implemented methods:

CommonButtonInterface
  Sub Method1

Class CommonButtonHandler
  Sub DoMethod1
    MsgBox("Do it!")
  End Sub

Class A Inherits From PushButton, Implements CommonButtonInterface
  Private Property mCommonStuff As CommonButtonHandler

  Sub Constructor
    mCommonStuff = New CommonButtonHandler
  End Sub

  Sub Method1
    mCommonStuff.DoMethod1
  End Sub

Class B Inherits From BevelButton, Implements CommonButtonInterface
  Private Property mCommonStuff As CommonButtonHandler

  Sub Constructor
    mCommonStuff = New CommonButtonHandler
  End Sub

  Sub Method1
    mCommonStuff.DoMethod1
  End Sub