OJB to Hibernate 3 Migration

I've spent far too long on this already so I'll make this brief but still try to help others out who want to go through the same process.

To convert your repository_user.xml file to a hibernate mapping file, try using this stylesheet. It's not completely automatic. I still had to add inverse="true" attributes in a few places were we're using bi-directional associations (see section 2.3.6 of the Hibernate Reference Documentation).

I also needed to tweak a few proxy attributes because we're using Castor XML which turned out to make things much more difficult. Hibernate uses CGlib for what it calls proxy generation. The problem is that it changes the class signature of the original class it's proxying for. When the modified classes get sent to Castor it complains about illegal/invalid characters because the class name is now suffixed with $$EnhancerByCGLIB$$. I had to patch the Castor source with a hack. Still looking for a long term solution.

Before all that mess I spent some time trying to figure out why Hibernate wasn't reading my JNDI datasource resource. It complained about an empty driver setting and a null URL. For those issues, refer to this helpful forum thread. Not the solution I was hoping for but it works.

Update:

I'm posting the change I made to Castor in response to a comment but it's pretty embarrassing :) These lines went below line 1293 of org.exolab.castor.xml.Marshaller in version 0.9.5.3 (notice the second if condition):

            if (!containerField) {
                //-- Make sure qName is not null
                if (qName == null) {
                    //-- hopefully this never happens, but if it does, it means
                    //-- we have a bug in our naming logic
                    String err = "Error in deriving name for type: " +
                        _class.getName() + ", please report bug to: " +
                        "http://castor.exolab.org.";
                    throw new IllegalStateException(err);
                }
                if( qName.indexOf("$$-enhancer-by-cGLIB$$") != -1 ) {
                    return;
                }
                handler.startElement(qName, atts);
            }

Lovely solution, right? Hope it helps you, Michael.