Injecting JPA's Entity Manager in Hibernate's EmptyInterceptor

Question

I am using JPA-2.0 with Hibernate in my data access layer.

For audit logging purposes, I am using Hibernate\'s EmptyInterceptor by configuring below property in persiste

Answer 1

I am considering persistenceManager initiated successfully in your Abstract class. You may Have a class AuditLogDAO which extends your AbstractDao. Inject AuditLogDAO class into your interceptor and call auditLogDAO.save(entity); and other methods.

Or write a Util class which perform DB operations and inject the util class to your interceptor.

Answer 2

I have got a simple way to perform database operation using JPA Entity Manager in 'AuditLogInterceptor'

I have created below class that will give the application context reference:

@Component("applicationContextProvider")
    public class ApplicationContextProvider implements ApplicationContextAware {
        private static ApplicationContext context;

        public static ApplicationContext getApplicationContext() {
            return context;
        }

        @Override
        public void setApplicationContext(ApplicationContext ctx) {
            context = ctx;
        }
    }

Created Data access class:

@Repository("myAuditDAO")
public class myAuditDAO<T, ID extends Serializable> {

    private final transient Class<T> persistentClass;

    protected transient EntityManager entityManager;

    @SuppressWarnings("unchecked")
    public MyDAO() {

        this.persistentClass = (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
    }

    @PersistenceContext
    public final void setEntityManager(final EntityManager entityMgrToSet) {

        this.entityManager = entityMgrToSet;
    }

    public final Class<T> getPersistentClass() {

        return persistentClass;
    }

    public final T findById(final ID theId) {

        return entityManager.find(persistentClass, theId);
    }

    public final void persist(final T entity) {

        entityManager.persist(entity);
    }

    public final void merge(final T entity) {

        entityManager.merge(entity);
    }
}

And used 'ApplicationContextProvider' in 'AuditLogInterceptor' to get the reference of 'MyAuditDAO' that is having JPA entity manager as a property which is injected during DAO initialization. Now with the help of 'MyAuditDAO' I can perform database operations.

public class AuditLogInterceptor extends EmptyInterceptor {  

    @Override  
    public void postFlush(Iterator iterator) throws CallbackException {  

      // Here we can get the MyAuditDao reference and can perform persiste/merge options
       MyAuditDao myAuditDao = (MyAuditDao ) ApplicationContextProvider.getApplicationContext().getBean("myAuditDao");

      //  myAuditDao.persist(myEntity);

    }  
}