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On Mon, Nov 29, 2004 at 08:52:49PM -0800, Dare Obasanjo wrote:
> So SOA is RPC with a calling convention for methods? Sounds silly to me.
> I like Don's four fundamentals of service orientation from
> * Boundaries are explicit
> * Services are autonomous
> * Services share schema and contract, not class
> * Service compatibility is determined based on policy
> It's basically a philosophy on how one should treat building distributed
> application instead of a way to repackage yesterday's technology with
> today's buzzwords so one can charge an arm and a leg for building
> applications with tomorrow's toolkits.
> I especially like the fact that it's quite easy to see how RESTful
> applications are service oriented using those guiding principles.
I like them too because they're constraints of a sort. But they are
also pretty vague, and therefore don't provide a whole lot of guidance
for developers. Perhaps if they were expanded upon, so that each
described, in architectural terms, *exactly* what was constrained,
they'd be of greater value (yes, I've seen the expanded version, but
it still falls short IMO). It would certainly allow others to
constructively critique them. As is, they seem a bit "motherhood and
apple pie" to me, akin to "Components shall not be tightly coupled", or
"The interface shall not expose implementation details".
It's also interesting to note that Don is still promoting RPC based SOAP
services (via his use of wsa:Action), so it seems these tenets of his
don't exclude it. I think that's a significant deficiency.
Mark Baker. Ottawa, Ontario, CANADA. http://www.markbaker.ca