Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!sirius.ucs.adelaide.edu.au!fang!dch
From: dch@aeg.dsto.oz.au (Dave Hanslip)
Newsgroups: comp.object
Subject: Re: OOA vs OOD (was: Booch GOOD - Coad/Yourdon BAD)
Keywords: ooa, ood
Message-ID: <1289@fang.dsto.oz>
Date: 8 Nov 90 16:27:17 GMT
References: <0B010001.gv7aox@bse.com>
Sender: news@fang.dsto.oz
Lines: 46


eberard@bse.com (Edward V. Berard) writes:


>... However, I make the following observations:

>	1. If you are not predisposed to rigorous software engineering, and
>	   you have a traditional object-oriented programming background,
>	   you will probably feel most comfortable with things like CRC (Class,
>	   Responsibilities, Collaboration) cards and responsibility-driven
>	   design. [These approaches do introduce a good deal of object coupling
>	   and do not seem to work well with medium to large projects.]

>	2. If you come from a more traditional software engineering background
>	   (e.g., structured and data modeling approaches), you will find
>	   Coad/Yourdon and Shlaer/Mellor to be more comfortable. You will
>	   also find, however, that these approaches are only partially
>	   object-oriented. (Although, they are evolving.) This means that
>	   some of the promised advantages of an object-oriented approach
>	   may not be fully realized.

>	3. Even if you feel most comfortable with Booch's new book, there
>	   will be pieces missing. Booch does not address the beginning of
>	   the life-cycle in depth, for example.

>				-- Ed


>----------------------------------------------------------------------------
>Edward V. Berard                                | Phone: (301) 353-9652
>Berard Software Engineering, Inc.               | FAX:   (301) 353-9272
>18620 Mateney Road                              | E-Mail: eberard@bse.com
>Germantown, Maryland 20874                      | 
>----------------------------------------------------------------------------

As one currently grappling with applying OOD to a very large project, I must agree with the final sentence of para 1.

I recall a statement I saw on the net some months back that large system design should proceed sequentially through steps of SA/SD and OOD. In my experience, with a laand very complex system, if one commences with OOD, one is overwhelmed by complexity. Commencing with SA/SD allows smaller less complex subsystems to be identified to which OOD (a la CRC cards) can then be applied. SA/SD (or functional decomposition if you like) is then again applied within classes to member functions.

With regard to Booch's new book, I found guidance on subsystem selection and subsequent integration of subsystems to be missing. Also, how to achieve this integration (both organisationally and practically) using a language such as C++. Course, I'm not complaining, it's exciting working in a new area, breaking new ground, going boldly where no man has gone before (sorry, boldly going where nobody has gone before!).



David C. Hanslip                              E-mail: dch@aeg.dsto.oz.au
Aeronautical Research Laboratory              Phone: +61 8 259 5792
DSTO Salisbury, South Australia               Fax: +61 8 259 5507