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Re: Process instantiation puzzle

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Sat, 20 Sep 2003 15:09:36 -0400
To: www-ws@w3.org
Message-Id: <F9F63B2F-EB9D-11D7-8C02-0003939E0B44@isr.umd.edu>

On Saturday, September 20, 2003, at 02:09  PM, Drew McDermott wrote:

>    [me]
>> So my followup question is: Where in DAML-S (if anywhere) do we
>> specify the correlation tokens in messages?
>
>    [Bijan "the Mighty Doorprize Winner" Parsia]
>    We totally punt on that. I regard this as a problem.
>
> I think introducing some structure here would deconfuse us in several
> areas where the semantics of DAML-S is still fuzzy.

I, in some sense, agree, though I'm not sure that the semantics are  
fuzzy so much as unspecified. And, I think, probably contrary to you,  
that there are advantages to having this information only appear at  
somewhat lower abstraction layers.

That might be too strong.

I am looking at part 10 of the BPEL spec:
	http://www-106.ibm.com/developerworks/webservices/library/ws-bpel/ 
#correlation

"""The information provided so far suggests that the target for  
messages that are delivered to a business process service is the WSDL  
port of the recipient service. This is an illusion because, by their  
very nature, stateful business processes are instantiated to act in  
accordance with the history of an extended interaction. Therefore,  
messages sent to such processes need to be delivered not only to the  
correct destination port, but also to the correct instance of the  
business process that provides the port. The infrastructure hosting the  
process must do this in a generic manner, to avoid burdening every  
process implementation with the need to implement a custom mechanism  
for instance routing. Messages, which create a new business process  
instance, are a special case, as described in 6.4. The Lifecycle of a  
Business Process. """

I guess this ok, (though I'm not convinced that the idea that a  
stateful process *is instantiated* and hangs around is quite correct;  
think of my interaction with a hotel, I may interact with any number of  
reservation clerks over the course of getting things set up and I have  
some sort of tracking number that facilitates those clerks interacting  
with me sensibly; state about our transactions is shared between those  
clerks (some of which may be at the hotel, others at a national center,  
etc); there's *some* sense in which this can be modeled as a single,  
instantiated process (and some sense in doing so); the question to my  
mind is which level of detail, and which representation, is necessary  
or useful for accomplishing what reasoning or execution, etc task?)

[snip]
> P.S. *Everybody's* invited to my "Now I'm rich" party.  Just send me a
> self-addressed stamped envelope along with your name, social security
> number, mother's maiden name, and a bank-account number.  (I need
> this so I can deposit the door prizes that just about everyone is
> going to win.)  I will send you an Official Invitation printed on
> guaranteed 8.5x11 paper.

What are the snacks going to be like? Is this going to be co-located,  
like everything else in the known world, with ISWC?

Cheers,
Bijan Parsia.
Received on Saturday, 20 September 2003 15:08:48 GMT

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