[rules-users] Drools Flow / Declarative process definition

[Kris Verlaenen]

Jaroslav,

Yes, if you execute your processes in advanced mode, we are translating 
procedural constructs like sequence into a more declarative rule like the 
one you described as an example.  Note we are currently not doing that for 
all procedural constructs (like branch / joins) but we plan to extend these 
integration points over time.

This does allow you to execute a process without having explicit connections 
between all nodes.  We like to describe this as process fragments, where you 
have small, not-connected flow fragments and where the rules or the user can 
define when each fragment should be executed, etc.  This could then be 
event-based, data-based, user-triggered, etc.  Instead of the process 
controlling everything, we see this as an inversion where your rules will be 
controlling the process fragments.  This is however still work in progress 
(meaning a lot is already possible if you dive into it, but we definitely 
need to extend the tooling etc. to better harness this power before we 
unleash this to our users).  I'm hoping to do a blog entry about this soon, 
to show some direction.  If you're interested in this, it's also related to 
flexible or ad-hoc processes, adaptible case management, etc.

Drools currently targets the Java space primarly.  But this doesn't mean you 
can't use if for XML processing.  At this stage, this could become rather 
complex as we don't provide high-level constructs yet to manipulate this XML 
data, so you'd have to either build this yourself or do more low-level XML 
manipulation.  As part of our move to BPMN2, we are however planning to 
seriously enhance this, by adding XPath as a constraint language dialect, 
better web service integration (as part of our integration with the ESB and 
the entire SOA platform), etc.

Kris

----- Original Message ----- 
From: "Jaroslav Pullmann" <jaroslav.pullmann at fit.fraunhofer.de>
To: <rules-users at lists.jboss.org>
Sent: Friday, February 26, 2010 2:47 PM
Subject: [rules-users] Drools Flow / Declarative process definition


>
> Dear Drools team,
>
>  I like much the approach of Drools Flow and would appreciate to learn 
> more.
>
>  The documentation states the extended rule engine having knowledge of the 
> process model
>  and instance state derives the next process execution step. I am 
> wondering, whether the
>  overall flow is reactive, even the procedural constructs like sequence, 
> branching/joining
>  are implemented through firing rule actions ? For example, does Drools 
> Flow converts the
>  sequence of steps A -> B into sth. like "when A.passed then B.start()" ?
>
>  When the prevoius holds, does Drools Flow allows to create (desgin) and 
> execute declarative processes
>  omiting any explicit sequencing ? The steps/tasks were ordered partially 
> by data- or event-based
>  dependency conditions or even activated independently of each other.
>
>  Drools Flow/Expert provide a thight integration with Java (e.g. 
> representing facts as Java classes).
>  Are there future plans for supporting a higher-level processing with 
> XML/XPath/XQuery like in YAWL ?
>
>   Many thanks
>    Jaro
>
>
>
>
> -- 
> Jaroslav Pullmann
> Web Compliance Center - Fraunhofer FIT
> Schloss Birlinghoven, D-53757 Sankt Augustin, Germany
> Phone: +49-2241-142623    Fax: +49-2241-142065
> _______________________________________________
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