More Advanced Features - Beginning Hibernate: From Novice to Professional - page 252

By obtaining a JDBC connection from the session, it is of course possible to invoke stored
procedures directly; however, you must be aware that the Hibernate session cache cannot
track these updates.

Events
Hibernate 3 actually implements most of its functionality as event listeners. When you regis-
ter a listener with Hibernate, the listener entirely supplants the default functionality. For
example, the EJB 3-specific behavior required when using an EntityManager is achieved by
plugging in a set of EJB 3-specific event listeners!
If you look at the methods of the SessionImpl class, which is the internal Hibernate
implementation of the Session interface, you'll see why this is the case. Most of the meth-
ods have a form very similar to that shown in Listing A-21.

Listing A-21. The Implementation of a Typical Method in SessionImpl

SaveOrUpdateEvent event = new SaveOrUpdateEvent(entityName, obj, this);
listeners.getSaveOrUpdateEventListener().onSaveOrUpdate(event);

The listeners field is an instance of SessionEventListenerConfig , which provides the
requested event listener, or the default if none is specified. So, if your event listener is provided
and doesn't call the default one, nothing else can.
Event listeners are always registered globally for the event that they handle. You can regis-
ter them in the configuration file or programmatically. Either way, you will need to map your
implementation of one of the interfaces to the associated types, which you can look up in
Table A-1. (The names are almost—but not quite—standardized.)

Table A-1. The Listener Names and Their Corresponding Interfaces

Type Name Listener

auto-flush AutoFlushEventListener

delete DeleteEventListener

dirty-check DirtyCheckEventListener

evict EvictEventListener

flush FlushEventListener

flush-entity FlushEntityEventListener

load LoadEventListener

load-collection InitializeCollectionEventListener

lock LockEventListener

merge MergeEventListener

persist PersistEventListener

post-delete PostDeleteEventListener

post-insert PostInsertEventListener

post-load PostLoadEventListener

post-update PostUpdateEventListener