[ebbp] 10/10/2004: BPMN Use in ebBP

["Monica J. Martin" <Monica.Martin@Sun.COM>]

On 7 Oct 2004 Thursday, we had a good session with the BPMN team re: 
support for business collaboration.  Here are a few highlights of the 
discussion thus far:

    * Most BPMN Collaboration typically (most often) doesn't involve an
      intermediary managing the collaboration. It is peer-to-peer.
    * In the notation, evaluate need to recognize the BSI that is the
      interface for that part for the business collaboration. BSI
      verifies collaboration conformance to the description.
          o (paraphrase of St. Amand comment) Looking at the BSI, the
            endpoint is an abstract event, a boundary.  The start,
            intermediate and end are instantiations of that boundary in
            BPMN.  We actually need the abstract event.
          o [my comment] This to me represents a type of sorts.
    * BPMN can visualize:
          o The message flow and associate with a sequence (see comment
            below)
          o An event-based gateway (could support Decision for example)
          o Can represent:
                + Transactions (subprocess focused) [see comment below]
                + Events
                + Timers

Discussion items:

    * Pending from 7 October
          o May need extensions for BT patterns.
          o Expressing bi-directional (capable of either side
            initiating) behavior [1]
          o Represent possibility of multiple requests and responses.
          o More on the abstract interface - Is it explicitly modeled?
            re: BSI.
    * Others [2]
          o Exceptions - BPMN allows an exception event. However, it is
            understood in the context of compensation. (May be more
            future item).
          o BPMN recognizes tokens that exist 'with' the message flow
            and appear to represent guards on a state transition. Do we
            need to consider or include?
          o What benefit could we get from using the 'sequence" element
            enforceable in BPMN? Could it be like a constraint?
                + BPMN considers a process without a pre-defined
                  sequence to be ad hoc. Our patterns are anything but
                  ad hoc but I am uncertain if the constraint is on
                  execution in sequence or a design constraint that
                  recognizes a sequence is at least expected.
          o Is a subprocess rich enough for composition use?

We will meet again with BPMN in October. Team members are also welcomed 
to attend. Details will be forwarded when available.

[1] See Change PO in example from White. This will be revised given the 
discussion.
[2] My inputs

References:

   1. Our initial draft submission (example only):
      http://www.oasis-open.org/archives/ebxml-bp/200409/msg00008.html
   2. White example 2 (BPMN):
      http://www.oasis-open.org/archives/ebxml-bp/200409/msg00078.html
   3. Highlights of the BPMN spec relevant to ebBP (Thanks to Sally St.
      Amand):
      http://www.oasis-open.org/archives/ebxml-bp/200410/msg00030.html
   4. BPMN session notes, 7 Oct (also available in Kavi Documents
      section):
      http://www.oasis-open.org/archives/ebxml-bp/200410/msg00045.html
   5. Dubray updated diagram for BPMN (working draft):
      http://www.oasis-open.org/archives/ebxml-bp/200410/msg00042.html
      and http://www.oasis-open.org/archives/ebxml-bp/200410/msg00037.html