How to register hibernate spring entity listeners - spring

Question

I have built an entity listener but have not figured out how to register it so that it will get called. This all runs, and I verified in the debugger that the
registration code executes (apparently successfully) at startup. But the debugger never stops in the listener code.
This is my listener:
public class DirtyAwareListener implements PostLoadEventListener
{
#Override
public void onPostLoad(PostLoadEvent postLoadEvent)
{
if (postLoadEvent.getEntity() instanceof DirtyAware)
{
((DirtyAware)postLoadEvent.getEntity()).commitFields();
}
}
}
and this is the registration component:
#Component
public class HibernateListenerConfigurer
{
#PersistenceUnit
private EntityManagerFactory emf;
#Autowired
private SessionFactory sessionFactory;
#PostConstruct
protected void init()
{
DirtyAwareListener listener = new DirtyAwareListener();
// SessionFactoryImpl sessionFactory = emf.unwrap(SessionFactoryImpl.class);
EventListenerRegistry registry = ((SessionFactoryImpl)sessionFactory).getServiceRegistry().getService(EventListenerRegistry.class);
registry.getEventListenerGroup(EventType.POST_LOAD).appendListener(listener);
}
}
Here is how my general Hibernate configuration code generates a session factory:
LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
sessionFactory.setDataSource(getDataSource());
sessionFactory.setPackagesToScan("com.my.entities");
sessionFactory.setHibernateProperties(getHibernateProperties());
sessionFactory.setEntityInterceptor(new DirtyAwareInterceptor());
return sessionFactory;
Note that the interceptor does work as expected (but unfortunately does not have hooks where I need them.)

Answer 1

To add entity listeners implement org.hibernate.integrator.spi.Integrator. See example https://www.boraji.com/hibernate-5-event-listener-example

Answer 2

I got this working as desired using the Integrator approach as Anton suggested. The link provided in his answer did not provide sufficient information for me to get this to work - I had to reference multiple posts and also do a bit of trial and error. Since I could not find a single post which provided the info, here is how I did it:
The listener code is the same as the above. The Configurer code is not needed - I deleted it. Here is the new Integrator code:
#Component
public class EventListenerIntegrator implements Integrator
{
#Override
public void integrate(Metadata metadata, SessionFactoryImplementor sessionFactoryImplementor, SessionFactoryServiceRegistry sessionFactoryServiceRegistry)
{
EventListenerRegistry eventListenerRegistry =
sessionFactoryServiceRegistry.getService(EventListenerRegistry.class);
DirtyAwareListener t = new DirtyAwareListener();
eventListenerRegistry.getEventListenerGroup(EventType.POST_LOAD).appendListener(t);
}
#Override
public void disintegrate(SessionFactoryImplementor sessionFactoryImplementor, SessionFactoryServiceRegistry sessionFactoryServiceRegistry) {}
}
And here is the revised getSessionFactory method on my #Configuration class:
private static SessionFactory sessionFactory = null;
#Bean
public SessionFactory getSessionFactory()
{
if (sessionFactory == null)
{
BootstrapServiceRegistry bootstrapRegistry =
new BootstrapServiceRegistryBuilder()
.applyIntegrator(new EventListenerIntegrator())
.build();
StandardServiceRegistryBuilder registryBuilder =
new StandardServiceRegistryBuilder(bootstrapRegistry);
registryBuilder.applySetting(org.hibernate.cfg.Environment.DATASOURCE, getDataSource());
registryBuilder.applySettings(getHibernateProperties());
StandardServiceRegistry registry = registryBuilder.build();
MetadataSources sources = new MetadataSources(registry).addPackage("com.my.entities");
sources.addAnnotatedClass(User.class);
Metadata metadata = sources.getMetadataBuilder().build();
sessionFactory = metadata.getSessionFactoryBuilder().build();
}
return sessionFactory;
}
Note: I think the addPackage call is not needed and does not do anything. I had hoped it would do the package scan the old code was doing, but it does not do that. I simply changed that to explicity add each annotated class.