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Re: Preconditions /effects vs Preconditions/Postconditions

From: Monika Solanki <monika@dmu.ac.uk>
Date: Tue, 16 Sep 2003 14:04:31 +0100
Message-ID: <3F670A5F.9030202@dmu.ac.uk>
To: www-ws@w3.org

Drew McDermott wrote:

>   [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 am  not sure, when you say "Web service developer", it means :

(a) The guy who is actually providing such a service and therefore also 
providing all the models with it
(b) The guy who has actually all the models before him and trying to put 
them together for a specific goal.

If it is (a) (which I strongly believe it is) then, I believe it is 
necessary for him to actually identify the required parameters to ensure 
that his service is indeed usable by other agents for whatever task - 
discovery, composition etc.

>   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 understand that prescribing the fact about how to use, includes 
identifying all the details like IOPEs as well, or am I missing 
something. I am not sure what is meant by other uses. Now whatever means 
are used in identifying/prescribing those (provider or third party)do 
not really matter or do they?

>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.
>
>  
>
I believe, it does not really matter if the service developer (provider) 
maintians it himself or delegates it( This could be a hidden fact as 
well). As long as the properties are available, everything should be fine.
-- 
**>><<**>><<**>><<**>><<**>><<**>><<**>><<**
Monika Solanki
Software Technology Research Laboratory(STRL)
De Montfort University
Hawthorn building, H00.18
The Gateway
Leicester LE1 9BH, UK

phone: +44 (0)116 250 6170 intern: 6170
email: monika@dmu.ac.uk
web: http://www.cse.dmu.ac.uk/~monika
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Received on Tuesday, 16 September 2003 08:58:58 GMT

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