Hibernate version: 2.1

Hibernate is working properly.. I'm looking for a pattern to apply in this case.

Situation: I have a service receiving a transient, updated copy of an object called Host. If certain fields are changed on the Host then there are dependent fields on other objects that will be updated to reflect the change**. Obviously determining whether or not fields have changed necessitates loading the 'actual' copy and comparing the fields before saving the new version. In order to prevent a NonUniqueObjectException from being thrown when the transient copy is being saved, the 'actual' copy is evicted from the session after examining its elements.

This works on a small scale, but is very fragile as the number of conditions and side effects increase. What did technically work, and seems to be safer, is flushing/cleaning the session before calling update on the transient Host object. However, that is less efficient and doesn't seem ideal either.

Is there a recognized pattern for handling incoming transient objects and making sure this conflict doesn't occur?

Thank you for any ideas..

**Copious amounts of business logic and caching should be assumed, which precludes triggers handling the side effects on the db side.

select-before-update in the mapping file may help you ;)