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RE: Use Cases & Requirements

From: Jean-Jacques Dubray <jjd@eigner.com>
Date: Sat, 17 May 2003 14:37:32 -0400
To: "'Yaron Y. Goland'" <ygoland@bea.com>, "'WS Chor Public'" <public-ws-chor@w3.org>
Message-ID: <009901c31ca3$73cd0990$0502a8c0@JJD>

Yaron:

Thanks for taking the time to write this paper, I think it makes a very
important and clear distinction between CPL and CDL, which fit well with
Martin's definition of orchestration.

I agree pretty much with everything you say, except for one point: you
are talking about "prose" and "non-executable logic". I strongly
disagree with that point.

If it is true that as a global view, a CDL does not have an engine to
ensure its execution, one of the value of a machine processable CDL is
that each party can validate the choreography of messages based on rules
defined in a CDL. So for me it is a requirement that the "prose" you are
talking about be machine processable.

Again, if you are a big organization, you are going to receive in the
order of 100,000 to 1,000,000 messages per day. Having a CDL that help
you validate whether or not you are supposed to receive any of these
messages before you start processing them is going to save a lot of code
within each application (not too mention that a given choreography could
involve multiple of your applications, which would compound the
problem).

However there is catch when expressing this business logic. In order for
each participant to "know" the state of the choreography, this business
logic can only be expressed on the information being exchanged by any
two parties. For instance we could not have a transition "if I approved
your order" because the buyer has no way to know this information from
the supplier unless you specifically exchange a message containing this
information. This type of information becomes "prose". Interestingly
enough, the business logic of CPL is the prose of CDL.

Cheers,

Jean-Jacques Dubray____________________
Chief Architect
Eigner  Precision Lifecycle Management
200 Fifth Avenue
Waltham, MA 02451
781-472-6317
jjd@eigner.com
www.eigner.com 
 
 

>>-----Original Message-----
>>From: public-ws-chor-request@w3.org
[mailto:public-ws-chor-request@w3.org]
>>On Behalf Of Yaron Y. Goland
>>Sent: Freitag, 16. Mai 2003 21:20
>>To: WS Chor Public
>>Subject: Use Cases & Requirements
>>
>>
>>I would like to submit the following use cases and requirements for
>>consideration by the working group -
>>http://lists.w3.org/Archives/Public/www-archive/2003May/att-0029/chor.
htm.
>>
>>Besides providing what I personally believe to be critical
requirements
>>for
>>the success of the working group I also think they help to outline
what I
>>believe to be the fundamental differences between what I think the W3C
>>Choreography WG should be doing and what the BPEL OASIS TC is doing.
Of
>>course all opinions on such differences are mine and mine alone, your
>>mileage may vary, objects in mirror are closer than they appear.
>>
>>		Yaron
Received on Saturday, 17 May 2003 14:41:19 GMT

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