[JP] Day 1 - Business Rules and Drools

Mark Protor who leads the Drools project gave first an overview over the history of Drools and BusinessRules and the thinking behind them.
Some of Marks statements to Drools/BusinessRules:

  • Rules are mainly like SQL with many mathing tables and joins.
  • OR is something dangerous and should be avoided where possible. Often missused by beginners.
  • Rules are the Knowledge Expert System, Facts are hold in the Working Memory and PatternMatching between the two causes actions to fire

    As an example of how Drools fires actions an how to control flow via semaphores Marc went through Fibonacci calculation to show us how recursion works the "Drools-Way"

    Great Pluses for Drools/BusinessRules:

  • + BusinessAnalysts understand the rules
  • + BusinessAnalysts can change them and therefore feel responsible for them and the rules are always up-to-date
  • + BusinessAnalysts can identify interference between rules
  • + it is easy to change the rules, so if you deal with often changing rules, give a BusinessRules a try
  • + with JMS you are able to change the rules, without a redeploy of an application, which sounds very nice
  • + only changed items cause a reevaluation. Everything else will not be recalculated

    Minus for Drools/BusinessRules:

  • - high learning curve since it is a different paradigma than coding in a programming language
  • - Performance problems if not applied correctly, can be solved with better knowledge
  • - the learning curve
  • - if you do not have at least a week of free time to experiment with it, forget it. There is a high learning curve involved!!!

    All in all the presentation was far to fast - considering non native speakers, non Drools-Experts being in the audience. One slide came fast after the other with quick explanations which just scratched the surface.

    Posted by Karsten at 12.12.05 20:02 | TrackBack
  • Comments


    Thanks for the feedback. It's always difficult to decide what to put into presentations and the pace to take them at. I think you were right at the end of it I did feel rushed, I wanted to try and show as much as possible, I think in the future I'll concentrate more on the basics and some higher level features. I think I'll definitely drop the fibonacci and manners examples. Instead I'll show execution control with a much simpler example and will only mention manners with regards to benchmarking without going into detail.

    Of course you can always guarantee that people will then complain I didn't show any meat :)

    This was our first big presentation and we will only improve, especailly as we start to build up the manuals and training material.



    Posted by: Mark Proctor at 27.12.05 00:39

    Hi Mark,
    it's nice to know that u are open for feedback.
    Wish u the best in upcoming presentations,

    Posted by: Karsten Voges at 27.12.05 09:27
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