I would like to continue the discussion just starting in the JIRA comments of Issue #JBPM-2006 here in the forums. And I would like to encourage a discussion about it. I like Bernd's idea of discussing "best practices" and different ways of integrating.
For me a real integration would allow the end-user to use the rules repository (Drools Guvnor) but at the same time it would be nice to enable them to use a serialized rule base as well.
As far as I overlook the situation a rule would be used from within a DecisionHandler class or instead of one - depends how you implement this.
One would be in need to specify which rule should be retrieved and be called from the repository. Furthermore you would need to specifiy which variables should be used as input for the rule. Since we are talking about general business rules the result would not necessarily be the name of the transition to take. So you would be in need to map a specific result of the rule evaluation to the name of the transition to take.
Is there anything wrong with my idea of using rules? Which approach would need more effort? The serialzed rule base or the repository approach?
Afaik, Tom already has a serialized rule base prototype working on his machine - which is basically the functionality which existed for jBPM3 (somewhere on the wiki).
None of the approaches is 'a lot' of work, they just need prioritization ;-)