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RE: BPMN Collaboration Processes?

From: Ugo Corda <UCorda@SeeBeyond.com>
Date: Wed, 3 Mar 2004 18:23:15 -0800
Message-ID: <EDDE2977F3D216428E903370E3EBDDC9032B8A70@MAIL01.stc.com>
To: "Prasad M. Jayaweera" <prasad@cc.ruh.ac.lk>, <public-ws-chor@w3.org>

(Sorry for responding on the list about a subject that is out of scope
of WS-Chor. I just thought that people on this list who are interested
in modeling notation for choreographies might still want to hear BPMN
WG's response to Prasad's original question. They are also welcome, of
course, to send me any feedback they might have, so that I can forward
it to the BPMN list).

Prasad,

BPMN provides the flexibility for modelers to create both internal
process models (orchestrations) and choreographies. The use of BPMN
swimlane features can be used to organize process activities for these
purposes. There are two ways of organizing activities: 

First, through Pools, which represent a group of activities that are
semi-independent from other groups of activities. Pools can only
interact with each other through the exchange of messages--not through
normal "control flow." 

Second, through Lanes within a Pool. Lanes create a swimlane capability
for organizing activities according to one or more modeling criteria.
Lanes would often represent organizational departments, user roles,
systems, etc. However, a modeler is not restricted in how a Lane can be
defined. Thus, they can serve for both orchestration and choreography
processes. 

BPMN activities do come in different types and they can also be extended
according to one or more modeling criteria. 

To get a more concrete idea, please consider the following examples:

- The example at
http://www.bpmn.org/Samples/Choreography/DoctorVisit/Visit1.htm shows
how Pools can be associated with internal processes a-la BPEL. Each one
of the BPMN sequence flows contained in a Pool could be mapped to a BPEL
process. Messages exchanged between pools would correspond to messages
(e.g. SOAP messages) exchanged between the Web services corresponding to
each BPEL process.

- Depending on the application, a somewhat different view might be
required. The example at
http://www.bpmn.org/Samples/Choreography/DoctorVisit/Visit1-a.htm is the
same as the previous one, except for the additional dotted boxes
grouping together particular binary interactions that the application
wants to focus on.

- The previous example can be rewritten once again as a single Pool with
three Lanes:
http://www.bpmn.org/Samples/Choreography/DoctorVisit/Visit5.htm . The
dotted boxes in the previous example have turned into the regular boxes
appearing on each Lane, and the individual messages are now represented
using the big arrows inside each box. This could be the view
corresponding to a global process view like WS-Choreography. Instead of
focusing on the behavior of individual internal processes, this view
focuses on the various binary interactions that characterize the global
process, and how they should be sequenced in order to satisfy the
corresponding choreography.

Ugo

> -----Original Message-----
> From: public-ws-chor-request@w3.org 
> [mailto:public-ws-chor-request@w3.org] On Behalf Of Prasad M. 
> Jayaweera
> Sent: Tuesday, February 24, 2004 6:11 AM
> To: public-ws-chor@w3.org
> Subject: BPMN Collaboration Processes?
> 
> 
> 
> Hi BPMN experts,
> 
> I would be thankful to you all if anybody can clarify me with the 
> followings. 
> 
> In the 
> http://www.bpmn.org/Documents/NWG-2003-08-01R2%20BPMN%201-0%20
Draft.pdf 
there is some text about Collaboration (Global) processes as, 

"Collaboration processes may be contained within a Pool and the
different 
participant
business interactions are shown as Lanes within the Pool. In this
situation, 
each Lane
would represent two participants and a direction of travel between
them." 

I guess, in this situation, a lane will be representing binary 
collaboration. 

But in the figure 2 of 
http://www.enix.co.uk/Documents/The%20Split%20Personality%20of%20BPM.pdf

(source BPMN Working group) a Collaboration Process Model has been
modeled 
as Abstract Processes that communicate through message exchange only. My

understanding is this is some what different approach to the text in
BPMN 
(1.0) 

Can anybody clarify me how one can model collaborations with BPMN and if

possible direct me some example BPMN collaboration process models. 

Thanks! 

/Prasad
Received on Wednesday, 3 March 2004 21:23:46 GMT

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