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From: Dmitry A. Kazakov on 24 Feb 2007 03:33
On 23 Feb 2007 12:19:23 -0800, Nathan wrote:

> So would you advocate keeping the high level engine class as a
> 'controller' that can handle the deletion of the object regardless of
> when the actual data was deleted?

Yes.

Further "actual data was deleted" is poorly defined. Does it mean an
incoming deletion request, disappearance of the last reference to the
target object, finalization of the later? IMO one of the design goals is to
define the precise meaning of "Delete."

--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
From: H. S. Lahman on 24 Feb 2007 13:02
Responding to Nathan...

> Interesting what you say about the factory handling deletion, I'd
> never heard of that.

Yeah, I've never understood why it doesn't get more press. It seems
pretty obvious, given OO encapsulation, though. The rules and policies
of instantiation (Who) are usually different than those of collaboration
(What & When), so it makes sense to encapsulate them away from
individual collaborations via "factory" objects and patterns.

But the rules and policies of de-instantiation are pretty much a mirror
image of those for instantiation. In addition, one is dealing with
exactly the same concerns: referential integrity (relationships) and
data integrity (initialization and availability). One uses objects to
encapsulate logically related concerns. So where else would one put that
logic?


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