Hi, I just want to save you some trouble by informing about the importance of returning correct values in you Interceptor.
I have a combined audit-log and set-default-values interceptor and I could not understand why I got two calls to onFlushDirty when I did saveOrUpdate, (resulting in two audit-log records for each update).
Then I read the javadoc part that said you must return true in onFlushDirty and onSave if you modify state. After I implemented that I only get one call to onFlushDirty. I took me a few hours to figure out, and it was clearly stated in the doc (as always :-)
I saw some other posts asking about multiple calls to onFlushDirty, maybe this info can be of help to you.

/Goran

Hibernate version: 2.1.6