Issue 16548: BPMN 2.0 Choreography issues page 338  of dtc/2010-06-05 about Sub-choreographics (bpmn2-rtf)
Source:  (, )
Nature: Uncategorized Issue
Severity: 
Summary: On Page 338 of /dtc/2010-06-05/, about Sub-choreographies:


    “The Participant Band of the Participant that does not initiate the
    interaction MUST be shaded with a light fill.”


    This wording does not cover some corner cases. Consider the example
    depicted in the attached image Example Issue Initiating Participant
    in Sub-Choreographies.png. In the choreography above it is unknown
    until the enactment of Task 1which participant is the initiator of
    Sub-choreography 1. But this is only the symptom of a wider-reaching
    problem. When there is no choreography task that dominates of all
    the others (or worse, there is a race condition!), and the various
    choreography tasks that may be executed as first have different
    initiators, modelers have no way to pick which participant is marked
    as the initiator of the sub-choreographies.


    The same issue with initiators of sub-choreographies affects also
    the messages sent by them. In fact, Page 93 of /dtc/2010-06-05/reads:


    “Any Message sent by the non-initiating Participant or
    Sub-Choreography MUST be shaded with a light fill.”


    We propose two possible, mutually exclusive solutions:


     1. Additional constraints are specified for choreographies so that
        no such corner case can occur. However, this is very likely to
        result in not being able to model with BPMN 2.0 choreographies
        some inter-organizational processes that can instead be modeled
        with BPMN 2.0 Orchestrations.
     2. Drop the differentiation between initiator and non-initiator
        participants in sub-choreographies. We see no real shortcoming
        resulting from this approach. In particular, with respect to the
        enactability of choreographies, knowing which participant is the
        first to act in a sub-choreography gives no guarantees as to the
        fact that the same participant will also be involved in the
        “last” choreography activities to be executed in that
        sub-choreography. Therefore, we can extract no useful
        information from it with respect to the enactability of what
        follows that sub-choreography. This is particularly true in the
        case of collapsed sub-choreographies.


Resolution: 
Revised Text: 
Actions taken:
September 14, 2011: received issue
Discussion: 

End of Annotations:=====
s is issue # 16548	from <michele.mancioppi@iaas.uni-stuttgart.de

BPMN 2.0 Choreography issues page 338  of dtc/2010-06-05 about Sub-choreographics

On Page 338 of /dtc/2010-06-05/, about Sub-choreographies:


    âThe Participant Band of the Participant that does not initiate the
    interaction MUST be shaded with a light fill.â


    This wording does not cover some corner cases. Consider the example
    depicted in the attached image Example Issue Initiating Participant
    in Sub-Choreographies.png. In the choreography above it is unknown
    until the enactment of Task 1which participant is the initiator of
    Sub-choreography 1. But this is only the symptom of a wider-reaching
    problem. When there is no choreography task that dominates of all
    the others (or worse, there is a race condition!), and the various
    choreography tasks that may be executed as first have different
    initiators, modelers have no way to pick which participant is marked
    as the initiator of the sub-choreographies.


    The same issue with initiators of sub-choreographies affects also
    the messages sent by them. In fact, Page 93 of /dtc/2010-06-05/reads:


    âAny Message sent by the non-initiating Participant or
    Sub-Choreography MUST be shaded with a light fill.â


    We propose two possible, mutually exclusive solutions:


     1. Additional constraints are specified for choreographies so that
        no such corner case can occur. However, this is very likely to
        result in not being able to model with BPMN 2.0 choreographies
        some inter-organizational processes that can instead be modeled
        with BPMN 2.0 Orchestrations.
     2. Drop the differentiation between initiator and non-initiator
        participants in sub-choreographies. We see no real shortcoming
        resulting from this approach. In particular, with respect to the
        enactability of choreographies, knowing which participant is the
        first to act in a sub-choreography gives no guarantees as to the
        fact that the same participant will also be involved in the
        âlastâ choreography activities to be executed in that
        sub-choreography. Therefore, we can extract no useful
        information from it with respect to the enactability of what
        follows that sub-choreography. This is particularly true in the
        case of collapsed sub-choreographies.