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Re: DAML-S ProcessModel

From: Sudhir Agarwal <agarwal@aifb.uni-karlsruhe.de>
Date: Sat, 17 May 2003 15:55:53 +0200
To: www-ws@w3.org
Message-Id: <200305171555.53942.agarwal@aifb.uni-karlsruhe.de>

Massimo,

thanks for the quick and detailed reply. I helped me to understand some things 
that were unclear to me. Could you please explain me, what you exactly mean 
by the term "interaction protocol"? or give me some pointers to the documents 
where it is explained? I looked into the DAML-S description, but did not find 
anything like that.

Thanks.
Sudhir.

On Friday 16 May 2003 18:53, Massimo Paolucci wrote:
> Sudhir,
>
> There are many reasons why a Web services may want to display its
> process model.  The first one is that its clients can derive the
> interaction protocol from the Process Model.  For example a book
> selling Web service like Amazon allows you to browse and to reserve
> the book (amazon's web service does not allow to buy right now).  so
> you could have a process model that looks like
> sequence(browse-atomic-process, reserve-atomic-process).  The client
> at this point knows that first it has to deal with the browsing
> task, then with the reserve task.  Acting differently from what the
> process model require will lead to errors.
>
> But there are other reasons.  I understand that supply chain
> management depends on the providers to provide information on the
> state of processing of the different orders.  Ultimately this requires
> the providers to display parts of their process model.  Also, during
> composition of web services clients need to know details on how the
> web service performs its tasks so they can integrate different
> serices.  For example, before spending some money a client may want to
> make sure that there is money in an account.  This requires careful
> composition of the process model of the selling Web service (which
> withdraw the money from the account) with the process model of the Web
> service of the Bank that holds the account (which tells if there is
> enough money).
>
> Ultimately, the DAML-S Process Model allows implementors of Web
> services to display as much of the Web service they want to display.
> If they do not want to display anything, they use only one atomic
> process.  Minimally, they have to display enough information to allow
> their clients to derive the interaction protocol, and in a way this is
> what e-shops do already (amazon or orbitz ask you quite a few
> questions before letting you to buy something) everything else it is
> up to their business model and what they want to achieve.
>
> I hope that this helped,
>
> --- Massimo
>
> Sudhir Agarwal writes:
>  > Dear all,
>  >
>  > i currently can not understand the purpose of the ProcessModel
>  > completely. I understand why an AtomicProcess is needed. But, why does
>  > ComplexProcess exist? Isn't it enough to have only AtomicProcess? Why
>  > should a web service provider show how his services works? On the other
>  > hand, im not sure that a web service requester is interested in knowing
>  > all that (if-then-else, while, split, fork etc.) stuff as long as the
>  > service does what he wants. Even if someone really wants to know that,
>  > what can he do with that knowledge? Does it help him in any way?
>  >
>  > could someone help me?
>  >
>  > Thanks and regards
>  >
>  > Sudhir
Received on Saturday, 17 May 2003 09:58:03 GMT

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