Wednesday, 20 May 2009

Making A Callstack Persistable

Another one of David Chappell's great workflow writings: The Workflow Way. In this article, David explains the essence of workflow and BPM engines. Typically, the BPM vendors try too much to link their engines to the business value of managing processes properly, thereby obscuring what BPM engines actually do from a software standpoint.

BPM engines are different from plain programs like Java, C, Cobol etc in 2 key aspects:

1) The runtime state is persistable. At any point during execution of a process, the process execution can be interrupted and stored. Later the execution state can be retrieved from persistent storage and continued.

This is essentially different from plain computer programs where the callstack is not persistable. Blocking plain programs keeps thread resources and that doesn't survive reboots of the computer system.

The capability of interrupting an execution, storing it, retrieving it and resuming the execution can also be described as support for wait states.

2) Graphical representation. The second aspect where BPM processes differ from plain programs in languages is that BPM processes are aimed to be represented graphically with boxes and arrows.

David's article is an easy to read article for understanding these two aspects in more detail and learn what BPM and workflow engines really are made for.

Tuesday, 12 May 2009

jBPM Community Day Report

Last week Friday, we had the second jBPM Community Day. With over 40 people again a well attended event. For those who missed it, here's an impression.

The first part of the day, the core developer met up to discuss the interesting low level tech details.

At 3pm, I kicked it off with an overview.

Then quickly people needed a break.

Then Eric Schabell, who joined JBoss just last week, introduced the talk about the SNS bank use case, where he worked before.

Maurice de Chateau from SNS Bank gave a good impression of how jBPM was used in practice. It turned out there sometime there are some practical problems between dream and reality.

Then Joram Barrez gave an awsome demo connecting jBPM with his cellphone over bluetooth to pay for a parking space.

Those who don't quit easily joined us for food.

And the die hards joined us for drinks :-)

jBPM 4.0.0.Beta2 Released

Give this Beta2 release a try. Lot's of things were improved. Feedback appreciated.