Creating objects question

[David Pantale]

I have an object orientation question, which I'm not sure there really is a good general answer to (and which nobody may care about!). But here goes, when creating an object that will be contained by another object, what is the best way to create the inner object? Should you create the inner object outside the containing object and use a setObject method to place it in the containing object, or create it from within the container object(after passing in any data necessary for the creation)? Obviously this could often be situation dependent, but does anyone have an opinion as to a general preferred method?

Thanks
Dave

[Stephan van Hulst]

Like you said, it depends. If the relation between the objects is a simple association or an aggregation, then I generally prefer to create the second object externally. However, in a composition it's better to create it inside the first object.

Classes should be easy to use. If a class can do all the work by creating its own internals, it should definitely do so.