Rule Modularity and Execution Control Enhancements for a Java-Based Rule Engine

Drools is a popular and well known Java-based production rule system. Production rule systems, like Drools, present challenges when applied to large and complex systems. This industrial paper evaluates the prior art with regards to rulebase modularity and execution control. It then looks at how that can be applied to Drools and what further enhancements can be made. Consideration is given to ensure the work is more palatable for developers in a Java-based rule environment. Venus and RuleWorks are identified as two differing \textit{state of the art} systems. Venus provides a decoupling of rules and data as well as a declarative guard based system, without life cycle callbacks. RuleWorks provides imperative subroutines with lifecycle callbacks.