I have a class SocPatient.java with a corresponding table Soc_Patient and a hibernate mapping file SocPatient.hbm.xml.

I extended this class in order to add two non-persisted booleans (which I only need to keep around for JSPs) in the following fashion:


, and then remapped all formerly used SocPatients to use SocPatientChild wherever needed.

Now when I run the application, I keep getting MappingExceptions on SocPatientChild when a previous calls to save the SocPatients were being executed.

I tried a few different things:

1) created a SocPatientChild.hbm.xml mapped to table Soc_Patient with the same content as SocPatient.hbm.xml (failed with some other exception)

2) upcasted SocPatientChild to SocPatient before attempting the SAVE
e.g. (SocPatient) socPatientChild

3) got desperate and tried cloning (made no difference!)

In the end, I managed to solve the problem by using a combination of upcasting and copy constructor, BUT I WONDER IF THERE'S A BETTER WAY:

Thanks for any help,
-melina

At the point you save the object you can tell hibernate what you want it saved as like this:



As these additional fields are solely for you jsp it might be worth considering creating a separate class that _contains_ a SocPatient and the extra fields rather than extending SocPatient.

Solution #1: I like this solution, that's exactly what I was trying to do (but through upcasting which didn't work).

Solution #2: including SocPatient inside the SocPatientChild rather than extending it would've been a bit more intrusive since it would've required remapping all of the functionality to add the extra socPatientchild.getSocPatient() call in order to access SocPatient's members.

You're right about #2. One way around this is to create delegate methods which map to the contained object. Eclipse for example has an automated delegate generator which does the job for you.