Question

I have an objectA from ClassA which has a List of objects from ClassB.

Can I access objectA from objectB? I mean, I’m asking if there are something like objectB.getListOwner() which returns objectA.

I know I can have a ClassA atribute on ClassB and set it with objectA when I create objectB but I’m wondering if there are something more direct.

Answer 1

Not directly or automatically.

What you can do is have a method in ClassA such as addToList(ClassB objectB)
and what this does is the following:

public void addToList(ClassB objectB)
{
  objectB.setClassAOwner(this);
  list.add(objectB);
}

And you use that method to add ClassB objects to the list of ClassA.

Obviously ClassB needs to have a method setClassAOwner(ClassA owner) and the respective member variable ClassA owner, and most probably a matching getter method getClassAOwner()

Small comment with regards to this approach. This introduces a direct cyclic dependency, which is, more often than not, undesirable from a Design principle point of view for various reasons outside scope of this question. But it achieves what you want.