Re: OOA?

From: Robert C. Martin (unclebob_at_objectmentor.com)
Date: 01/16/04 

Date: Thu, 15 Jan 2004 19:58:59 -0600

Shane,

I have heard nothing but good things about Eric's book. I have it on
my pile of books to read, near the top.

Others who know my work and his work can comment as to whether there
is any disconnect. I suspect there is not, given what I have heard.
But I'll wait until I read the book to comment more.

Understanding the domain, and building models of the domain to aid
that understanding, is a useful and necessary activity for software
developers and business analysts -- it always has been. I have no
idea what that has to do with OO.

On Fri, 16 Jan 2004 09:29:52 +1300, "Shane Mingins"
<shanemingins@yahoo.com.clothes> wrote:

>"Robert C. Martin" <unclebob@objectmentor.com> wrote in message
>news:s8dd00loa3jlser3n6pfgr1oejguetmvvb@4ax.com...
>> Bottom line: You can't expect people who don't know how to code to
>> write OO domain models that can be used to generate code.
>
>Agreed. And I hope I did not give the impression that I was suggesting
>otherwise.
>
>I do not want to get into the detail of Real vs Integer etc as I will
>quickly fall out of my depth mathematically so I will respond to this
>thread.
>
>You have now talked about a model of the problem domain vs a model of the
>solution which then explains the statement "What this tells me is that "OO
>Models" of the problem domain do not naturally translate well into an OO
>program".
>
>When I read that statement about OO Models I was thinking of a domain model
>and domain driven design as described in Domain-Driven Design - Eric Evans.
>If I understand correctly what you are referring to vs what Eric is, the
>domain model in DDD is modeling the solution.
>
>There is a site for the book with some sample chapters
>
>http://www.domaindrivendesign.org/book/index.html
>
>Have a read of the Part I intro:
>http://www.domaindrivendesign.org/book/evans_pt01.pdf
>
>He later states:
>
>"Ultimately, we hope to develop a model that captures a deep understanding
>of the domain. This should make the software more in tune with the way the
>domain experts think and more responsive to the user's needs." Pg 188.
>
>What I am trying to understand is where Eric's ideas sit in context of yours
>(and Ron's) as I endeavour to form my own.
>
>Given that Eric's book is supported by Martin Fowler, Kent Beck, Ralph
>Johnson, & Ward Cunningham I am accepting that the ideas within are not
>something that the XP/Agile community reject.
>
>What I am trying (unsuccessfully at the moment) is to try and reconcile
>other views on domain modelling (predominantly yours) versus this book.
>Somewhere I feel there is a piece missing.
>
>Also I am also trying to understand how domain-driven design fits in with XP
>and TDD. I have been referred to a newsgroup post that I will paste below.
>
>Regards
>Shane
>
>
> From: Joshua Kerievsky <joshua@i...>
> Date: Thu Oct 23, 2003 5:50 am
> Subject: Re: [industrialxp] Timing for Domain-Driven Design in
>Industrial XP
>
>
>
>
> Chris Gardner wrote:
>
> >When do you typically apply Eric Evan's domain driven design
> >techniques in Industrial XP? Do you try to capture a model just
> >before coding? In the iteration planning meeting? etc.?
> >
> >
> I think of Evolutionary Design as being the big umbrella for the
> following design practices:
>
> * Story Test-Driven Development (STDD)
> * Test-Driven Development
> * Refactoring
> * Domain-Driven Design (DDD)
>
> Our practice of DDD flows out of our continuous practice of STDD and
> TDD, since many of our storytests and unitests are focused on proving
> that pure business logic executes as expected.
>
> DDD also influences our language, for we endeavor to speak with our
> project community using a Ubiquitous Language.
>
> DDD also influences our choice to keep domain logic code totally free
>of
> non-domain-specific code, such as database, networking or ui code.
>
> Does that help?
>
> best regards
> jk
>
>
>
>
>
>
>

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