about processes and engines

Archive for the ‘yawl’ Category

workflow patterns and open source wfms

Petia Wohed just announced the latest version of Patterns-based Evaluation of Open Source BPM Systems.

Quoting Petia :

This document is a revision and extension of the BPM center report. For those of you, familiar with the earlier report, the technical evaluations has not changed. In the latest version we
have extended the outlook and improved the presentation.

I particularly like the final part of the new document where considerations for users and developers of open source workflow tools are offered.

Congrats to Petia and all the authors, it’s a huge amount of work.

(reminder : Petia just created a Google group about the Workflow Patterns)

Written by John Mettraux

August 8, 2008 at 12:52 pm

a google group about Workflow Patterns

This will mostly interest the workflow engine implementers among you, but also those who evaluate such projects or products.

Petia Wohed just created a Google Group about the Workflow Patterns.

From the Workflow Patterns website :

In process-aware information systems various perspectives can be distinguished. The control-flow perspective captures aspects related to control-flow dependencies between various tasks (e.g. parallelism, choice, synchronization etc). Originally twenty patterns were proposed for this perspective, but in the latest iteration this has grown to over forty patterns. The data perspective deals with the passing of information , scoping of variables, etc, while the resource perspective deals with resource to task allocation, delegation, etc. Finally the patterns for the exception handling perspective deal with the various causes of exceptions and the various actions that need to be taken as a result of exceptions occurring.

I have to admit I focus a lot on the control-flow perspective while implementing OpenWFE / OpenWFEru (ruote). I tend to leave the data and resource perspectives to the integrators (Ruby makes my life easier with that).

The google group :

The Workflow Patterns website :

Written by John Mettraux

July 25, 2008 at 1:31 am

Posted in bpm, workflow, yawl

Petia Wohed on YAWL at BPMinna

On Monday 30th of June, we were lucky enough to have a presentation by Petia Wohed of the Information Systems Laboratory of the University of Stockholm (and Royal Institute of Technology).

Petia contacted me last year while she was reviewing OpenWFE[ja] (and other open source workflow systems) in the light of the workflow patterns. I already blogged about the result of this work (see links at the bottom of this post).

Petia is a member of the YAWL project (workflow language and open source project) developed by the research groups of Prof. Wil van der Aalst and Prof. Arthur ter Hofstede. She delivered an excellent talk about this research effort and especially about the advantages of systems based on [Colored] Petri Nets (think Verification).

Before Petia’s presentation and my talk about OpenWFEru ruote, we had a demonstration by Zaky-san of iKnow! a social networking site for learning languages. It’s extremely successful in Japan (where it started) and it’s now expanding to the rest of the world.

Here is Petia’s presentation, it was graciously translated by Wakizaka-san to japanese :

What interested me the most was the worklet and the declarative workflow concepts. I will read carefully the papers they published about those.

Next was my talk about OpenWFEru, the slides are skinny, I rushed through them and then I demoed ruote-web, ruote-rest and the new fluo (process editing / rendering) :

Here are a few links :

(I’m certainly missing some blog reports, sorry)

Many thanks to Wakizaka-san and id:GoTheDistance for organizing those excellent BPMinna meetings (and many thanks as well to Sawada-san for inviting me to those meetings).

Written by John Mettraux

July 6, 2008 at 11:33 am

Posted in bpm, openwferu, oss, ruote, workflow, yawl

xpdl for fun

I took some time to implement a converter from XPDL to OpenWFEru’s process definition language.

Seems like a certain number of graphical process design tools do serialize their BPMN diagrams to XPDL. Pat has been bothering me about such a serialization for while.

I called that “ruote-transition”, it’s available at the GitHub. It’s not much work but it yields good results. I gave a shot a YAWL as well in the same run.

The challenge is about turning a states+transitions set into the “block structured” format OpenWFEru (Ruote) uses.

I already took a look at that in a former post, the trouble ticket. The transformation (from BPMN to OpenWFEru) was manual. The resulting process definition used a “macro” : a subprocess named “step” that handled the XOR outgoing transitions on the activities of the original process.

The “step” is back as a Ruote expression (like ‘sequence’, ‘concurrence’, ‘if’ or ‘participant’), part of the upcoming OpenWFEru 0.9.18. Ruote-transition [ab]uses this new expression a lot.

Ruote-transition has an intermediary representation format that is easy to output to graphviz format (example). I use it for quick verifications.

I call ruote-transition a “compiler”, turning from one language to another, “translator” would perhaps be a better term.

It was lots of fun to implement that (it’s not over). But I still favour OpenWFEru’s process definition language over anything else, I like its conciseness.

Don’t ask me for “round-tripping”.

Written by John Mettraux

May 18, 2008 at 1:04 pm

Posted in bpm, openwferu, workflow, xpdl, yawl