Re: Object-Oriented style question

[Maciej Sobczak <see.my.homepage@gmail.com>]

On Jan 10, 1:27 pm, Georg Bauhaus <rm.dash-bauh...@futureapps.de>
wrote:

> I wonder, though, whether the convention (using pointers to hint
> at lifetime and identity) could be turned into a different setup.
[...]

> The resulting types may entail more work, but perhaps also more
> flexibility. Suppose objects' lifetimes can be interrupted.
> For example, objects that can be "serialized" to external storage.
> They then seize to exist. Later, the program may load the objects
> from external storage, bringing them to life again. Perhaps on
> a different machine/node/partition. This might effectively mean
> that addresses of objects have changed.

This is essentially what object lifetime management in CORBA is
supposed to do. In principle, this is also a way to achieve
scalability by allowing objects (or rather their physical
representations) to materialize only when they are needed and be
"etherealized" otherwise. Transparent object migration is just one of
the possibilities here.

> Is this possible with pointers?

My experience with such approaches is that distribution cannot be made
fully transparent and attempts to do so result in severe problems[*]
(you cannot manage what you don't see). I can, however, imagine some
thick smart-pointer that provides this kind of functionality at least
at the design level.

[*] For more thoughts on why O-O and distribution don't work together
in the way that is typically expected, see:

http://www.inspirel.com/articles/RPC_vs_Messaging.html
http://www.inspirel.com/articles/What_Is_Wrong_With_IDL.html
http://www.inspirel.com/articles/Types_Of_Middleware.html

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com