True OO (Holub Style) using Aggregations.

[Zak Nixon]

I am trying to follow Holub's pure OO philosophy about OOA/D.

So in the light of that, who is responsible for adding an object to
a library (or list of elements).

- The element itself will know what list to add itself to.
- The library will create a generic object, place it in the list,
and return it to the calling application.
- Or, a controlling application that creates the library and elements, and physically adds them to the list.

Any thoughts?

[Ilja Preuss]

Originally posted by Zak Nixon:
I am trying to follow Holub's pure OO philosophy about OOA/D.

I'm curious - what is your motivation for doing so?

So in the light of that, who is responsible for adding an object to
a library (or list of elements).

I don't know what Holub would say, but to me it depends on what change patterns you observe/expect, that is, in which dimension(s) you need the design to be most flexible.

Can you tell us more about the objects and the library?

[Zak Nixon]

Well, my motivation.......

In my past projects in doing the same technique, it has
made modifications to the code very simplistic, including
more reusable across entire application.

My objects: Pretty simplistic object structure...

I have an interface called ClickAndDropObj which will be an aggregate
object in a list called ClickAndDropObjLibrary.

There are other responsibilites of the CNDObjLibrary. Once and CNDObj
is added, the library will update its view (being a self contained GUI).
So at all times the CNDObject will know how to display itself.

But, my real confusion is the following:
I want the best way to add these elements to the library, but who really
needs the responsibility of doing so? The element, library, or moderator ?

If it is the element, then the element would be coupled with the library.
Likewise with the library.
The moderator would be the glue between the lib and aggregates. Mainly responsible for adding,removing, updating the list.

So, is there any best way to do so ?

Thanks for reading my post....

[Ilja Preuss]

Originally posted by Zak Nixon:
So, is there any best way to do so ?

Well, using a mediator between the element and the list sounds like the most flexible solution. On the other hand, it might already be more complex than you need it *now*, and I would probably feel comfortable refactoring to a more flexible solution should I need it later.

So I guess it mainly depends on how your current needs are, and how comfortable you are about guessing future needs, in contrast to refactoring the design later.