Drools is an enhanced Rules Engine implementation, ReteOO, based on Charles Forgy's Rete algorithm tailored for the Java language. More importantly, Drools provides for Declarative Programming and is flexible enough to match the semantics of your problem domain with Domain Specific Languages.

Drools.NET is a Business Rules Engine (BRE) based on Charles Forgy's Rete algorithm. Developers can now exploit a powerful Rule Engine through a completely managed .NET code base! Drools.NET is based on Jboss Rules, and comes with all the features of that Rules Engine.