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Subject: [ebxml-cppa-negot] Re: BPSS Start element
<hima>inline Martin W Sachs wrote: > > > > > JJ, > > The spec shouldn't "handle bugs". What it should do is to enable enough > precision in a BPSS instance to allow a BSI to detect errors. > > You said "What we could add to the spec is an attribute which could > indicate that a given collaboration definition can only be used in nested > mode, otherwise an error is returned by the BSI." I agree that this can be > done. The point in my previous posting is that the spec "almost" does this > already because the Start element has minOccurs="0". So, your suggestion > could accomplished merely by adding a statement that if the Start element > is omitted from a binary collaboration, that binary collaboration can only > be used in nested mode. <hima> If the start element is omitted for internal collaboration, how would BSI figure out which BTA to initiate when collaborationAcitivity is initiated. </hima> > > > 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 > ************************************************************************************* > > > Jean-Jacques > Dubray To: Martin W Sachs/Watson/IBM@IBMUS, "'Jean-Jacques Dubray'" <jjd@eigner. > <jjd@eigner.com> com> > cc: ebtwg-bps@lists.ebtwg.org, ebxml-cppa-negot@lists.oasis-open.org > 08/09/2002 03:15 Subject: RE: BPSS Start element > PM > > > > Marty: > > I don't see why the spec should handle "bugs". If a bug is detected, a > few collaboration will be screwed up but someone can fix the bug and > then everything works just fine. Why would you think otherwise? > > What we could add to the spec is an attribute which could indicate that > a given collaboration definition can only be used in nested mode, > otherwise an error is returned by the BSI. > > Best regards, > > 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: Martin W Sachs [mailto:mwsachs@us.ibm.com] > >>Sent: Friday, August 09, 2002 2:56 PM > >>To: Jean-Jacques Dubray > >>Cc: ebtwg-bps@lists.ebtwg.org; ebxml-cppa-negot@lists.oasis-open.org > >>Subject: RE: BPSS Start element > >> > >> > >> > >> > >> > >> > >>JJ, > >> > >>OK, now how does this work? (The following use case is for the CPA > >>negotiation BPSS instance.) > >> > >>Using your notation, I have a collaboration A with start element > "start- > >>A". > >>Nested inside it, I have a collaboration B with start element > "start-B". > >>It is my intention that Collaboration B start only as a result of a > >>transition from Collaboration A. So, the choreography normally begins > >>with > >>the other party sending me document Da. Suppose that some business > >>partner > >>has a software error and attempts to start collaboration A but sends > >>document Db. That is an error and the BSI should signal an error. > How > >>will it know that starting with document Db is an error? > >> > >>I believe that there has to be something about the BPSS instance > document > >>that tells the BSI that each new instantiation is required to begin > with > >>document Da but I can't find anything. I hypothesize that I should > omit > >>start element start-B if I want each new instatiation to always start > with > >>document Da but I can't find any words that allow me to do omit > start-B in > >>order to force the BSI to flag an error if an instantiation starts > with > >>document Db. > >> > >>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 > >>********************************************************************** > **** > >>*********** > >> > >> > >> > >> "Jean-Jacques > >> Dubray" To: Martin W > >>Sachs/Watson/IBM@IBMUS > >> <jjd@eigner.com> cc: > >> Subject: RE: BPSS > Start > >>element > >> 08/09/2002 02:31 > >> PM > >> > >> > >> > >> > >> > >>Sorry, I did not understand the question like this. I don't see any > >>ambiguity unless both collaboration would start from the exact same > >>(logical) document. The BSI has a global view of all collaboration > >>definitions so it is not really important if they are nested or part > of > >>the same definition. If collaboration B is nested in collaboration A > and > >>Da (Db) is the document that starts the collaboration A (B) then when > Da > >>arrives as part of the first request, only Collaboration A can be > >>instantiated. Nothing prevents us to send Db in this case > collaboration > >>B would be instantiated. When a collaboration has started we then have > a > >>correlation for all subsequent message so we know how to distinguish > >>between a Db that starts a collaboration (no correlation) and a Db > that > >>starts the nested collaboration within collaboration A. > >> > >>Hope that helps, > >> > >>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: Martin W Sachs [mailto:mwsachs@us.ibm.com] > >>>>Sent: Friday, August 09, 2002 10:12 AM > >>>>To: Jean-Jacques Dubray > >>>>Cc: ebtwg-bps@lists.ebtwg.org; ebxml-cppa-negot@lists.oasis-open.org > >>>>Subject: RE: BPSS Start element > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>>JJ, > >>>> > >>>>Thanks for the reply. However, I would like to restate my question. > >>>> > >>>>One of the essential services a BSI can provide is to ensure that > >>everyone > >>>>is obeying the choreography described in the BPSS instance. That is > >>>>especially important in a world in which two trading partners may > have > >>>>obtained their application software from different vendors. In order > >>to > >>>>perform this service, the BSI must know what is the start of the > >>>>choreography. > >>>> > >>>>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? > >>>> > >>>>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 > >>>>******************************************************************** > ** > >>**** > >>>>*********** > >>>> > >>>> > >>>> > >>>> "Jean-Jacques > >>>> Dubray" To: Martin W > >>>>Sachs/Watson/IBM@IBMUS, <ebtwg-bps@lists.ebtwg.org>, <ebxml-cppa- > >>>> <jjd@eigner.com> negot@lists.oasis- > >>>>open.org> > >>>> cc: > >>>> 08/09/2002 09:31 Subject: RE: BPSS > >>Start > >>>>element > >>>> AM > >>>> > >>>> > >>>> > >>>> > >>>> > >>>>Marty: > >>>>>> > >>>>>>1. How does a BSI know the starting point of a choreography > defined > >>in > >>>>a > >>>>>>BPSS instance document? Is that the function of the Start > element? > >>>>If > >>>>>>not, what is the indicator? (It can't be preCondition since in BPS > >>>>1.05, > >>>>>>that attribute is for documentation only.) > >>>>>> > >>>>[JJ] The start element is used to "point to" the first business > >>>>transaction activity of the binary collaboration (actually nothing > >>>>prevents you to point to a fork element therefore enabling several > BTA > >>>>at the same time). The request of the BTA pointed to by the start > >>>>element is the message that will initiate the binary collaboration > >>>> > >>>> > >>>>>>2. If a BPSS instance contains more than one binary collaboration > >>(not > >>>>>>nested), are they treated as separate choreographies? Should each > >>>>have a > >>>>>>Start element? > >>>>[JJ] Yes they are completely independent and all should have a start > >>>>element. > >>>>>> > >>>>>>3. If a BPSS instance contains one "top-level" binary > collaboration > >>>>and > >>>>>>another binary collaboration nested inside it, should both binary > >>>>>>collaborations have start elements? If so, how does a deployment > >>tool > >>>>or > >>>>>>BSI know where the starting point is? It seems to me that it > would > >>>>have > >>>>>>to > >>>>>>analyze the flow in detail to figure out where the choreography > >>>>begins. > >>>>>> > >>>>[JJ] I don't see a probleme there, the start element is a > >>pseudo-state, > >>>>so in the case they are nested (as a Collaboration Activity in the > >>>>parent binary collaboration definition), the BSI will simply expect > >>the > >>>>next BTA will be the one pointed to by the start element of the > child > >>>>collaboration. In other words the BSI does not "stop" at this start > >>>>element, it automatically transitions to the BTA pointed to by this > >>>>element. You always need a start element to point to where you > start. > >>>>Otherwise, you would have to analyze all the transitions and detect > >>the > >>>>BTA that does not have a transition to it. > >>>> > >>>> > >>>>>>I have a suspicion that the answers are: > >>>>>> > >>>>>>1. The Start element is supposed to tell the BSI where the > >>>>choreography > >>>>>>starts. > >>>>>> > >>>>>>2. Non-nested binary collaborations are separate choreographies > and > >>>>each > >>>>>>needs a Start element. > >>>>>> > >>>>>>3. The nested binary collaboration should not have a Start element > >>>>since > >>>>>>the choregraphy starts with the top-level binary collaboration and > a > >>>>>>Transition element defines the starting point of the nested binary > >>>>>>collaboration. > >>>>>> > >>>>>>Am I right? > >>>>>> > >>>>>>Incidentally, BPSS 1.05 states that for the Start element, > >>>>>>maxOccurs="unbounded" although the text in 8.1.24 strongly implies > >>>>that > >>>>>>maxOccurs should be "1". > >>>>>> > >>>>[JJ] That could be a bug, I'll look into it. Conceivably, it is not > >>>>impossible to think of multiple start element, the question is > simply, > >>>>once such a collaboration has started to we disable the other start > >>>>element or do we leave them enabled? Note that this behavior can be > >>>>achieved with a single start followed by a fork (XOR or All) which > >>will > >>>>be followed by the corresponding BTAs. > >>>> > >>>>Cheers, > >>>> > >>>>JJ- > >>>> > >>>> > >>>>>>Regards, > >>>>>>Marry > >>>>>> > >>>>>>****************************************************************** > ** > >>** > >>>>**** > >>>>>>*********** > >>>>>> > >>>>>>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 > >>>>>>****************************************************************** > ** > >>** > >>>>**** > >>>>>>*********** > >>>>>> > >>>>>> > >>>>>>---------------------------------------------------------------- > >>>>>>To subscribe or unsubscribe from this elist use the subscription > >>>>>>manager: <http://lists.ebtwg.org/ob/adm.pl> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>>---------------------------------------------------------------- > >>>>To subscribe or unsubscribe from this elist use the subscription > >>>>manager: <http://lists.ebtwg.org/ob/adm.pl> > >> > >> > > ---------------------------------------------------------------- > To subscribe or unsubscribe from this elist use the subscription > manager: <http://lists.ebtwg.org/ob/adm.pl> > > ---------------------------------------------------------------- > To subscribe or unsubscribe from this elist use the subscription > manager: <http://lists.ebtwg.org/ob/adm.pl>
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