[rules-users] Design queries on use of Drools

Hi, I am working on a prototype of integrating our existing application with Drools, and would appreciate some advice/thoughts on my current design. We have an application through which messages flow, and at certain points in the process flow of these messages, business logic is encapsulated using Java-based exits. I want to replace these exits with business rules, and allow users to maintain the rules through Guvnor. I have created a fact model, and also a simple Java class to invoke the RuleAgent and execute my rules. At each processing step in my application, I would like to expose a different set of rules, so I have defined a package for each step, and assigned rules to the relevant package. At runtime, I am hoping I can then just expose my model class to the relevant set of rules for the processing step in question. Does this sound like the best way to use Drools to solve the problem? Any other considerations? Also, can anyone point me in the direction of some useful information about "functions" in the context of Guvnor? I would like to allow users to define rules using the Guided Rules editor to make decisions about dates, but the options available to me in the LHS of the editor don't seem to be rich enough, I am assuming I can create a function to wrap some extra processing logic which users can include in their rules? I can't find any good examples of how to define/write such functions though. Many thanks, Dave -- A. P. Herbert <http://www.brainyquote.com/quotes/authors/a/a_p_herbert.html> - "A high-brow is someone who looks at a sausage and thinks of Picasso."