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RE: Definition of Choreography

From: David Orchard <dorchard@bea.com>
Date: Sat, 19 Oct 2002 12:27:25 -0700
To: "'bhaugen'" <linkage@interaccess.com>, <www-ws-arch@w3.org>
Message-ID: <00d901c277a5$8f12fa50$5f1e11ac@beasys.com>

Bob,

This is a classic religious argument.  In the same way there are religious
battles over big-endian vs little-endian, strongly-typed vs weakly-typed,
interpreted vs compiled, etc., there will be battles of "condition based" vs
"explicit ordering".  While it is certainly true that condition based can
meet all the ordering requirements, there is an issue around usability.  For
example, I think coding up JSPs (explicit ordering) is about twice as easy
as XSLT (mostly condition based).  And I also have a metric that every time
you double the complexity, you lose 90% of the developers.  This is the
major reason why I'm not a big fan of condition based pipelines for xml or
web service processing models.  It's only pretty advanced developers that
use ANT and Makefiles, as yet another example.  I tend to think this is a
major reason why lisp and prolog didn't conquer the world compared to C,
C++, Java, VB.  Just debugging prolog is about 10 times as hard!  Don't get
me wrong, I think that the condition based is a great tool, but it has to be
acknowledged that there are certain types of users that we want to target
and understand their capabilities.

I have a requirement that it be as easy as reasonably possible to create
choreographies.  Which means I almost automatically prefer explicit ordering
instead of conditions.

Cheers,
Dave

> -----Original Message-----
> From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
> Behalf Of bhaugen
> Sent: Saturday, October 19, 2002 8:54 AM
> To: www-ws-arch@w3.org
> Subject: RE: Definition of Choreography
>
>
>
> What ordering requirements cannot be met by preconditions?
>
> Alternatively, what tangled knots will you weave as
> hard-coded sequences
> get into exception paths?
>
> I remember the evolution of Critical Path and PERT networks from I-J
> explicit links to predecessor links.  Predecessors were much
> simpler and
> more flexible.  And they could express any network that could be
> expressed with direct I-J links.  And they didn't require the dummy
> nodes that I-J networks needed.
>
> While it's not exactly the same problem, I think it's the same
> conclusion with preconditions vs hard-coded sequences.
>
> Or to put it another way, Web business processes are
> conversations, not
> work flows.
>
> -Bob Haugen
>
>
Received on Saturday, 19 October 2002 15:32:06 GMT

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