I've always stated that end business users struggle understanding the differences between rules and processes, and more recently rules and event processing. For them they have this problem in their mind and they just want to model it using some software. The traditional way of using two vendor offerings forces the business user to work with a process oriented or rules oriented approach which just gets in the way, often with great confusion over which tool they should be using to model which bit.

PegaSystems and Microsoft have done a great job of showing that the two can be combined and a behavioural modelling approach can be used. This allows the business user to work more naturally where the full range of approaches is available to them, without the tools getting in the way. From being process oriented to rule oriented or shades of grey in the middle - whatever suites the problem being modelled at that time.

Drools 5.0 takes this one step further by not only adding BPMN2 based workflow with Drools Flow but also adding event processing with Drools Fusion, creating a more holistic approach to software development. Where the term holistic is used for emphasizing the importance of the whole and the interdependence of its parts.

Drools 5.0 is now split into 5 modules, each with their own manual - Guvnor (BRMS/BPMS), Expert (Rules), Fusion (CEP), Flow (Process/Workflow) and Planner. Guvnor is our web based governance system, traditionally referred to in the rules world as a BRMS. We decided to move away from the BRMS term to a play on governance as it's not rules specific. Expert is the traditional rules engine. Fusion is the event processing side, it's a play on data/sensor fusion terminology. Flow is our workflow module, Kris Verlaenen leads this and has done some amazing work; he's currently moving flow to be incorporated into jBPM 5. The fith module called Planner, authored by Geoffrey De Smet, solves allocation and scheduling type problem and while still in the early stage of development is showing a lot of promise. We hope to add Semantics for 2011, based around description logc, and that is being work on as part of the next generaion Drools designs.

I've been working in the rules field now for around 7 years and I finally feel like I'm getting to grips with things and ideas are starting to gel and the real innovation is starting to happen. To me It feels like we actually know what we are doing now, compared to the past where there was a lot of wild guessing and exploration. I've been working hard on the next generation Drools Expert design document with Edson Tirelli and Davide Sottara. I invite you to read the document and get involved, http://community.jboss.org/wiki/DroolsLanguageEnhancements. The document takes things to the next level pushing Drools forward as a hybrid engine, not just a capable production rule system, but also melding in logic programming (prolog) with functional programming and description logic along with a host of other ideas for a more expressive and modern feeling language.

I hope you can feel the passion that my team and I have while working on Drools, and that some of it rubs off on you during your adventures.