[rules-users] Drools with Hibernate, with dynamic types

Hi, I'm gathering the requirements for an odd system project, and I have a design idea that is centered around Drools. I'd like to hear everyones opinion. The project is in a really early stage of conceptual analysis, and I'm also near the start on the winding road exploring Drools. The requirements call for a generic service application that performs database operations in response to service requests. Service logic should be editable by domain experts, not programmers. (Enter Drools Flow due to the procedural nature of the domain logic.) Trouble is, the exact database schema, thus the entity types are not known at compile time, only at the time of deployment. (In fact may differ across deployments.) So here's the idea: At deployment time I can convert the local database schema and domain logic description into both Drools rules/processes with type definitions, and matching hibernate/ibatis/JPA mappings for the java types defined via Drools. Drools would do the runtime bytecode generation for the entities and request objects its rules/process steps will operate on at deployment time. Then the ORM can instantiate the object network of entities from the database. (a few thousand entities, not a real big database.) All entities are inserted as facts in a forever-running session.* At each service request, the service connector would use reflection to create and populate a request object, and trigger a short-lived Drools Process. The user defined logic is executed, and if all went well, entity state is persisted back into the database for Durability. Servicing the requests sequentially is acceptable, so I'm not thinking about concurrency and Isolation yet. (I can always throw more worker threads at the problem with separate Working Memories, coupled by the L2 cache of the ORM I guess.) *: It's of course not critical for the KnowledgeSession to live forever: The working memory can be re-created from the database at any time. Does this sound doable? Is there any obvious flaw you guys can spot right away maybe? The alternative would be reading the database contents into Maps instead of typed entities with dynamically generated types, but that would drain all the elegance out of the Drools rules: when $p = PalpusztaiCheese(smell>11) then modify($p) { setQA("pass"); } end becomes when $m = Map() eval( "PalpusztaiChese".equals($m.get("type")) ) eval((Integer)$m.get("smell") > 11 ) then modify($m) { set("QA","pass"); } end (A DSL could completely hide this difference though, couldn't it?) Thanks for any ideas! Gabor Szokoli