Criteria query with restriction across a joined subclass problem

Question

I have the following graph:

OrderLine
    OrderLineExtension
        OrderLineExtensionA
        OrderLineExtensionB
        OrderLineExtensionC

OrderLine contains a Set of OrderLineExtension.
OrderLineExtension is defined as : @Inheritance(strategy = InheritanceType.JOINED) and is marked as an entity and is abstract

A table is created in the db for each of these classes in the hierarchy.

I'm trying to perform a query where the item name on OrderLine is "item", but where the is orderReferenceNumber "orderRef" in OrderLineExtensionA.

I'm not sure how to traverse from OrderLine to OrderLineExtensionA as there is no java reference from OrderLineExtension to OrderLineExtensionA.

I've so far got this which of course does not work.

filter=DetachedCriteria.forClass(OrderLine.class);
    .add(Restrictions.eq("item", "item"));
    .createCriteria("orderLineExtension")
        .add(Restrictions.eq("orderReferenceNumber", "orderRef"));

This fails as hibernate complains that it cannot find orderReferenceNumber in class orderLineExtension which is true as it's in orderLineExtensionA. But, how do I traverse to the extension? I cannot nest another createCriteria as there is no reference in the superclass to the subclass.

Any help would be appreciated.

Answer 1

Oops, don't worry. This problem is thrown up because I did not realise that a collegue had created the same field in each joined subclass. Hibernate will just go the the first subclass to load the property. This why i was getting the wrong instance back.

Now we have renamed them, it all works fine. Had my head scratching for a while though.