ERROR: RUL-00025:fact class multiple inheritance not supported

Question

I am receiving this erro message when trying to invoke a rule (assert, execute ruleset,retrieve results) on a XML Fact structure that has demo element as parent with a ref to two child elements: invoice and po.
I simply used the wizards to deploy the decide activity so I have no clue what this might be.
The rule session EVALUATEAPPROVAL:230011 failed to execute step assert
RUL-00025:fact class multiple inheritance not supported
oracle.rules.rl.exceptions.RLRuntimeException: fact class multiple inheritance not supported
     at oracle.rules.rl.exceptions.ExceptionFactory.createRuntimeMultipleInheritanceException(ExceptionFactory.java:467)
     at jess.DefinstanceList.autoDefclass(DefinstanceList.java:996)
     at jess.DefinstanceList.assertObject(DefinstanceList.java:570)
     at jess.Rete.assertObject(Rete.java:1557)

Answer 1

RL only supports single inheritance, either from an interface or a class. JAXB 1.0 generates a set of classes that inherit and implement each other. If the RL code is generated in the wrong order and child classes are generated before parent classes, then you get the indicated exception. In most cases, not importing the element class will prevent this from happening, and in the rest not importing the ObjectFactory class will prevent it (or unchecking the "supportsXpath" option). You can't use the element class in the rules anyway since the properties it inherits from it's parent don't show up in lists.
So, it's not the complexity of the XSD that matters in processing, only that a single inheritance chain is specified. If you follow the original instructions with your complex XSD, I believe you will see it work correctly.
This has been fixed in the as-yet-unreleased 10.1.3.4 version, but the only workaround for released versions is above.