[ebxml-cppa-negot] Re: BPSS Start element

[Martin W Sachs <mwsachs@us.ibm.com>]

John,

Thanks,  I believe you do understand what I am driving at.  I believe that
the reply I just posted to JJ is also appropriate to your posting but let
me restate in your terms:

I believe that if I want the nested collaboration to be treated as a state
machine encapsulated within the outer collaboration, I should state my
intention by omitting a Start element from the nested collaboration.  The
transition element in the outer collaboration will take me to the
encapsulated nested collaboration at the appropriate place in the
choreography without needing a start element in the nested collaboration. I
don't find words in the BPSS spec that tell me to do that,

Regards,
Marty

*************************************************************************************

Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287;  IBM tie line 863-7287
Notes address:  Martin W Sachs/Watson/IBM
Internet address:  mwsachs @ us.ibm.com
*************************************************************************************


                                                                                                                                        
                      "John Yunker"                                                                                                     
                      <john.                   To:       Martin W Sachs/Watson/IBM@IBMUS, "Jean-Jacques Dubray" <jjd@eigner.com>        
                      yunker@bleuciel.         cc:       <ebtwg-bps@lists.ebtwg.org>, <ebxml-cppa-negot@lists.oasis-open.org>           
                      org>                     Subject:  Re: BPSS Start element                                                         
                                                                                                                                        
                      08/09/2002 02:35                                                                                                  
                      PM                                                                                                                
                                                                                                                                        
                                                                                                                                        



<MWS> I have a BPSS instance two binary collaborations, one nested inside
the other, and both have Start elements. How does a BSI know which Start
element actually starts the choreography? </MWS>

Actually, this question is easily answered.  Since the collaborations
inherit from UML activity model, which itself is a state model, it is clear
that the outer collaboration "Start Element" starts the collaboration.
Now,
if the nested collaboration is part of the initiating business action, then
no messages are exchanged until the nested transaction starts.

This is actually a very important feature, since business state may dictate
that a collaboration is required.  That state can be expressed on the outer
start state, and still have conditions critical to the function of the
inner
transaction normalized to the inner transaction.  The fact the
collaboration
instance has been "started" is of value regardless of whether any message
exchanges have taken place.

So, to recap, the nested collaboration must be considered a state machine
encapsulated in an individual state within the encapsulating transaction,
(nested state machines) thus for the encapsulated collaboration to start,
the encapsulating collaboration must have started.

I can see incredible value in being able to normalize conditional elements
between the two start elements.

Thanks,
John

(p.s. I cannot post to the CPPA list, Marty, could you do it for me?
Thanks!!!)