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Re: Preconditions /effects vs Preconditions/Postconditions

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Tue, 16 Sep 2003 08:24:08 -0400 (EDT)
Message-Id: <200309161224.h8GCO8o05478@pantheon-po03.its.yale.edu>
To: www-ws@w3.org

   [Charlie Abela]
   I wonder whether it is expected for a Web Service developer creating such a 
   service to go into such a hussle as to identify all these possible combinations 
   of pre and postconditions, effects, you name it. 

   I think the more this is complicated the less it is looked at in a favourable 
   way. I also think that there should be some way by which to say that given a 
   number of preconditions and postconditions or effects then a service can be 
   identified, and other extended information regarding such service would be made 
   available in some other location, maybe also in some repository that defines 
   general business logic.

You've got a good point.  The major beneficiaries of a detailed model
of a web service are agents that want to reason about what it can do,
and in particular agents that want to combine it in creative ways with
other web services --- the "composition" problem.  Web services
themselves want to _prescribe_ how they are to be used; they have
little motivation to enable other uses.

I've always imagined that _third parties_ might produce more detailed
models of web services and get paid for keeping them up to date as the
services evolve.  E.g. amazon.com.com might maintain a declarative
model of amazon.com.

                                             -- Drew McDermott
                                                Yale Computer Science Department
Received on Tuesday, 16 September 2003 08:24:10 UTC

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