eventlisteners using hibernate 4.0 with spring 3.1.0.release?

Question

These jars are both new released and have the latest solutions for Java EE applications. But I have a problem on specifiying hibernate listeners in hibernate.cfg.xml.

Answer 1

The new approach is to use an Integrator to register the event listeners. Hibernate will now use service discovery for registering event listeners and here is how I got it to work using a maven archetype-webapp

create a file under META-INF/services (which should reside under your resources directory) called org.hibernate.integrator.spi.Integrator with all classes that implement the hibernate spi Interface, one line each. Short example below:

...

META-INF/services/org.hibernate.integrator.spi.Integrator

com.example.CustomIntegrator

com.example.CustomIntegrator

package com.example;

import ...;

public void CustomIntegrator implements Integrator {

    static final Logger logger = LoggerFactory.getLogger(CustomIntegrator.class);

    @Override
    public void integrate(Configuration configuration, SessionFactoryImplementor implementor, SessionFactoryServiceRegistry registry) {
        final EventListenerRegistry eventRegistry = registry.getService(EventListenerRegistry.class);

        logger.info("Registering event listeners");
        // you can add duplication strategory for duplicate registrations
        ...

        // prepend to register before or append to register after
        // this example will register a persist event listener
        eventRegistry.prependListeners(EventType.PERSIST, myListener);
        ...
    }

    ...

}

com.example.MyListener

package com.example;

import ...

public class MyListener implements PersistEventListener {

    static final Logger logger = LoggerFactory.getLogger(MyListener.class);

    public void onPersist(PersistEvent event) throws HibernateException {
        logger.debug("Entering MyListener");

        if(event.getObject() instanceof MyPersistableEntity) {
            MyPersistableEntity entity = (MyPersistableEntity) event.getObject();
            // do something with entity
            ...
        }
    }

    ...
}

Any entity that needs to have this event registered to it must implement MyPersistableEntity (not shown here)