On 2/28/06, Todd Biske <[EMAIL PROTECTED]> wrote:
> I don't disagree.  Perhaps my comments would have been better stated
> as the extent to which general vs. specific is a measurement of a
> well-defined interface is dependent on whether or not the business
> need is for a general purpose or for a specific purpose.

Sure.  But from all I've seen, businesses *need* loose coupling.  They
need implementation changes to remain hidden behind the interface so
as to not cause a cascade of follow-on changes, just to name one
benefit.

>  If an organization isn't prepared to change the services
> that it uses (either create new services and migrate consumers to
> them, or change the services that are in use, possibly changing
> consumers if needed), they are imposing rigidity into their IT
> systems, which is counter to the objectives of SOA.

Organizations should certainly be prepared to change their services;
I'm totally with you there.  But IMO, they should do it by changing
implementations, as changing interfaces is hugely expensive,
especially to their customers/partners who've written code that uses
those interfaces.  I think interface changes should be avoided
wherever possible.  And I think generic interfaces best support this
objective, as previously discussed (and which you appeared to agree
with - kudos).

Perhaps we just disagree about how often interface changes are
required in practice?  In my experience (yes, I do have considerable
experience with this approach 8-), it's *very* rarely necessary when a
fully generic interface is used.

Cheers,

Mark.
--
Mark Baker.  Ottawa, Ontario, CANADA.       http://www.markbaker.ca




 
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