drools

http://www.codeodor.com/index.cfm/2007/9/10/Rules-based-Programming-with-JBoss-RulesDrools/1600
http://drools.46999.n3.nabble.com/org-Drools-RuntimeRulesException-td58131.html
http://techgrafitti.wordpress.com/2011/02/21/drools-–-getting-started-hello-world-example/