I have a following scenario in which a complex logic (distributed over multiple .DRL files) need to process incoming jobs as fast as possible. A job definition looks something like describing what to do (type), what to process (item) with some additional data supplied (args). enum JobType { VALIDATE, SEND } class Job { String type; Object item; Object[] args; } In order to implement the processing I need to put the business logic into rules which fire depending on the kind of processing requested and type of the item passed: rule "process [VALIDATION] on [Document]" when $job: Job(type==JobType.VALIDATE) $doc: Document(issued==true) from $job.item then insert(new DocumentAlreadyIssuedFact()); end rule "process [SENDING] on [Message]" when $job: Job(type==JobType.SEND) $msg: Message() from $job.item then //do the sending end Unfortunately this does not work and results in ClassCastException being thrown, because it looks that Drools tries to cast any passed item to the class expected by the particular rule. In my opinion behaviour one can expect from Drools here is to first match the item class to the one expected by the rule and on success to perform the type casting. Is it a Drools bug or a missing feature? So after stidying the documention and example code I found only one way to workaround this – by using eval and instanceof which should have its performance implications due to extensive use of the eval. rule "process [VALIDATION] on [Document]" when $job: Job(type==JobType.VALIDATE) eval(($job.item instanceof Document)) $doc: Document(issued==true) from $job.item then insert(new DocumentAlreadyIssuedFact()); end rule "process [SENDING] on [Message]" when $job: Job(type==JobType.SEND) eval(($job.item instanceof Message)) $msg: Message() from $job.item then //do the sending end Such an implementation works, but I see it as some form of workaround as my feeling is that it will not allow the optimizations of Drools to shine. Please recommend more effective and elegant way of implementing this. Thank you in advance -- View this message in context: http://drools.46999.n3.nabble.com/Typecasting-problem-tp3412518p3412518.html Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users