Open Source Rule Engines in Java

Prova (from Prolog+Java) is a rule-based system for Java and agent scripting and information integration extending the Mandarax engine with a proper language syntax and enhanced semantics. The language breaks new ground in combining expressive and declarative programming. It combines natural syntax and typing of Java with Prolog-style rules and database wrappers. Java calls may include both constructor and method calls as wellas access to public variables in classes. Distributed and agent programming transported via JMS or JADE protocols is based on reaction rules specified in a natural syntax. The language makes it easy for agents to engage in concurrent conversations without starting new threads by using reaction and novel inline reaction rules in a very natural and ecoonomic syntax, directly capturing conversations as state machines.