This week OMG is putting on a 4-day workshop in San Francisco on Building a Service Oriented Architecture with BPM and MDA. Judging from the two sessions I attended, it’s really a good program, kind of an IT perspective on BPM. Yesterday I got the chance to meet Stephen White, one of the principal authors of the BPMN spec, and hear about what it is, how it works, and where it’s going… directly from the source.
In terms of what it is and how it works, I was surprised at the number of new things I learned in his session… since I have been back and forth over that spec many times in preparing my BPMN training. For example:
- Tasks in BPMN have a Type attribute, with defined values Service (the default), Send, Receive, Script, User, Manual, Reference, Abstract, or None. Depending on the value of the Task Type, certain message flows to or from the task are prohibited, and certain other attributes are required. According to Stephen, any real BPMN tool should enforce these validation rules. I am sure many do not.
- A message intermediate event in normal flow can either send or listen for a message event. You can’t tell from the diagram (unless a message flow is drawn). This might be legal but it seems bad practice. I think less ambiguous to use a Send or Receive Task instead.
- A sequence flow is “not a control flow” because the target activity could also be gated by other conditions, such as data flow. I dunno about this one. All simulation engines assume a sequence flow is a control flow.
- The exception flow from an error intermediate event can loop back to the same activity, essentially retrying it after the error handler. BPEL doesn’t allow this; following the fault handler, BPEL re-enters the process flow after the activity (scope) where the fault was caught.
These might seem in-the-weeds details but it shows how complicated even a seemingly simple standard like BPMN can be to understand.
As far as where BPMN going, I was a bit underwhelmed. Rumors of an imminent BPMN 2.0 last summer were nowhere close to the truth. In spring of 2007 we should see BPMN 1.1, which makes minor tweaks to the current spec, cleaning up the semantics of details such as Link events and Exclusive Merge gateways. BPDM and a schema for BPMN? Don’t hold your breath. When asked about this at his session, Stephen weakly offered WfMC’s XPDL 2.0. That’s not OMG’s official position, obviously. But to me, OMG’s lack of urgency on this issue is unconscionable. What about some kind of compliance guidelines, such as a list of MUST-SUPPORT objects and attributes? Today any tool that has rounded rectangles and swimlanes claims to be BPMN. Stephen was vague on this, but it sounded like a possibility. However, OMG will not be enforcing or certifying compliance.
BPMN 2.0 — the version that brings in BPDM, choreography, etc. — is still about two years away! The RFP should go out in the spring.
Bruce, sorry I missed you last week – perhaps I could have given you a bit more insight into the status of BPDM. Stephen, of course, is working the BPMN side of the house and doesn’t have as much insight on the BPDM details as the authors.
Short story is that it is on track to to be voted on at the December meeting … it should get the vote to go ahead, the only issue being whether the UML Profile (which is currently a requirement, although may be dropped in this initial release) is ready.
Now from a public face, IBM has a lot invested in the UML transform from BPMN, hence the degree of evasiveness when you asked Steve about it.
There is quite a bit of value in BPDM, which will bring some amazing capabilities – especially when you factor in support for both choreography and orchestration.
I am writing a paper on the whole set of OMG based standards which should come out pretty soon. The BPM Steering Committee will discuss it next week … the BPM SC is the business face for BPM stds inside the OMG.
In the end, BPDM is a pretty comprehensive work, which I have also been dissecting to see whether it will support things like Role Activity Diagrams as well … which is all about the choreography of process (rather than the orchestration aspect which is where BPMN is).
Here is what I have currently penned about BPDM, which gives you an idea of what it is all about, and where it is up to.
BPDM provides a ?meta-model? that enables the capture of semantic content from process models independent of the modeling notation. Think of it as a ?universal syntax? of process. The central idea is that BPDM is capable of supporting a mapping to the semantics of most common types of process model and, as much as is possible, thereby enables the robust exchange of information between models of that type and other types of process models, while preserving the fidelity of the model content.
To achieve this goal, BPDM must support two fundamentally complementary views of process ? orchestration and choreography:
? Orchestration is a term used to describe the traditional notion of sequential execution, where activities are carried out, with branching and synchronization of different threads.
? Choreography is a more ?abstract? notion of process. It is used to describe the coordination of the roles involved.
Moreover, the semantic content of a process models is separated from its graphical markup (enabling greater clarity).
Because of this sophistication, BPDM can support a very wide range of usage scenarios. For example, it enables high level, abstract ?business capability models? used in the boardroom, to exchange information with lower level, procedural modeling notations used in BPM projects, and then on into process execution environments (BPM Suites).
It could also facilitate the definition of complex inter-company business protocols (i.e. choreography). This model could be defined directly, or created through the composition of existing protocol fragments (from a library). The resulting model could then provide the terms of reference for each participants own internal orchestration model. In turn, this orchestration model could then be used to generate a robust BPEL execution model that directly supported the agreed choreography between the companies.
It is important to realize that these fundamentally different views of a process are based on different, yet related sets of semantic information. The point is that if these subtle differences are captured and mapped appropriately, then it becomes possible to effectively manage change?even down to capturing different scenarios, what-if analysis information and enabling rollback to previous versions.
In its initial form, BPDM is primarily intended to support the serialization of BPMN models. Work has already begun to develop a UML mapping, and a BPEL translation will be detailed in the appendices of the proposed standard.
The target audience for this standard are the business process modelling vendors and process execution vendors. Although important to the user community, it has no particular relevance to their day to day needs?i.e. the tools will either handle the translation or not.
At this point BPDM is going through the later stages of the OMG RFP process (Request For Proposal). The members of the work group are developing a joint submission that is due for presentation to the BMI Domain Task Force for review and acceptance at the December 2006 meeting in Washington. Thereafter, it goes to the Architecture Board for assessment and ratification. The standard will then be made available on the OMG web site (should be available by the end of January 2007).
It is already pretty much agreed by all parties that in the future, BPDM and what we now know as BPMN need to merge – become one and the same thing. BPMN has its own challenges – to better support the choreogfraphy side, to expand upwards to support a higher level notation for business modeling (if you like modeling business services or capabilities). And when Steve talks about BPMN 2.0, it is that effort that he is relating to.
Hope this helps clear up some of the confusion.
Desperate Men (Do Desperate Things)…
And given the importance of business process, and the new process platform that will replace ERP as the center of the business world, I think a few months is not too high a price to pay to get it right…. There is real business value here because wi…
Good to see Derek’s additional comments regarding BPDM, and I’m completely with you (Bruce) that OMG?s lack of urgency on this issue is unconscionable. Hopefully we’ll see some real movement in this area in the near future.