The real task developers have is trying to write and maintain the complex business logic in their applications, not only for new applications, but increasingly, for long-lived, business-critical apps whose internal logic needs to change frequently, often at very short notice. Until now, there was a gap in what the frameworks were able to do, in that business logic had no framework. Tools like EJB and Spring are good, but have little to say about how to organize your logic statements!

Guvnor is the new name for the BRMS. The term BRMS kind of has an industry meaning that is slightly different from what we call the Drools BRMS (when we say it, we mean the repository and web tools mostly). Hence, the name Guvnor (kind of related to governance - but really, it just sounds cool). On top of that, we are extending guvnor to manage other asset types - which aren't directly related to rules (but that's another story, for another day).

Mike is a hybrid rule engine by retired Open University Professor Marc Eisenstraat and Hull University's Dr Mike Brayshaw. The last release was version 2.50 in 1990 - so it's 18 years old. Mike formed part of the Open Universities "knowldge engineering" study pack. What's interesting is that 18 years ago they combined both prolog and rete for a hybrid reasoning system around frames (classes) - they even released the source code.

Using a rules engine can lower an application's maintenance and extensibility costs by reducing the complexity of components that implement complex business logic. This updated article shows you how to use the open source Drools rules engine to make a Java™ application more adaptive to changes. The Drools project has introduced a new native rule expression language and an Eclipse plug-in, making Drools easier to use than ever before.

Here at Zementis we have developed a decision engine called ADAPA – Adaptive Decision and Predictive Analytics (http://zementis.com/products.htm) that offers at its core batch and real-time scoring of predictive models as well as fast execution of business rules. As you readers might have guessed, the rules engine is Drools.