Validating entities before modifications in NHibernate

Question

I need to be able to validate some business rules on entities before any modification to DB is performed (Create, Update, Delete), and throw exception and rollback if these rules fail. I am building a framework and I want to do that always, despite whether user use my class to modify entities or directly NHibernate Session. I also need to be able to customize these business rules, depending on configuration file.

I've tried to inherit DefaultSaveOrUpdateEventListener, overriding PerformSaveOrUpdate, PerformUpdate, PerformSaveOrReplicate, PerformSave, OnSaveOrUpdate and DefaultSaveEventListener with overriding PerformSaveOrUpdate, PerformSave, PerformSaveOrReplicate, PerformUpdate, OnSaveOrUpdate. I just put Debug.WriteLine, and called the base implementation. I didn't find any good and detailed description of those, so I tried everything that seems like what I need.

And I have initialized them like this:

configuration.EventListeners.SaveOrUpdateEventListeners[0] = new SaveOrUpdatePermissionListener(_mappingContext);
configuration.EventListeners.SaveEventListeners[0] = new SavePermissionListener(_mappingContext);

But looks like this does not always work. If I modify objects in the object tree, for some reason these methods catch all objects except of the root object.

What I did wrong? Maybe there are better ways of doing what I want to do?

Answer 1

Was able to do that, by inheriting IPreUpdateEventListener, IPreDeleteEventListener, IPreInsertEventListener interfaces instead of DefaultSaveOrUpdateEventListener and DefaultSaveEventListener.

Still, if anybody has a better idea of achieving the task, I'm eager to listen.