Hi,

I have objects for which i must keep traces for each change done on attributs or relations (0-*)
for exemple
the class A is persistant and has one attributs (is name for example)
the class B is persistant and has relationship with A of type one-to-many (so a foreign key is created in A table)

1) when i save A i want to save halso an object of kind HistoricItem when precises that a new object is created
2) when i reload A and change the name and save i want to save halso an object of kind HistoricItem when precises that the object is change
3) when i add a A object to a B object, i want to to save halso an object of kind HistoricItem when precises that the A object has change

to do this i use a Interceptor implementation. 1) and 2) is done correctly and automatically
but for 3) i have a problem : information received in Interceptor never says that the A object has changed. And never says that the B object has changed

the surprise is that in the onFlushDirty method the content currentState and previousState is the same for the set of A object contained into the B object

could any one help ?
notice that my hibernate release is 2.0.3

Regards
Florent

The interceptor *does* fire if it is a bidirectional association, or if the parent is versioned.

I have also encountered the problem that the previous and current states for a collection are identical (the updated state) in the onFlushDirty interceptor.

My guess is that hibernate only keeps track of references, so that when you modify the collection, you are not changing the 'previous' reference and thus it still points to the modified collection.

A workaround for this is to create a new instance of the collection class whenever you want to modify it. If you're worried about allocating a new object each time, then track when you have the hibernate implementation class and allocate a new collection only then. The previous state will then reference the old hibernate collection and the current state your newly allocated one.

Note however that reallocating hibernate collections is generally considered bad form and won't work for an all-delete-orphan cascade.

I think trigger is better way to implement it. You do not need "HistoricItem" in model and it will work with all RDMS clients.