Best Practices for JPA Generated Keys

[Tim Holloway]

I've been working with Apache OpenJPA and a lot of what I do involves tables with generated integer keyfields. One of the problems with them is that since they're only generated when the backing store object has been created, the actual identity of the record is only available by retrieving the generated key.

For brute-force batch, I've been doing this:

  entityManager.getTransaction().begin();
  entityManager.persist(myRecord); // save data
  entityManager.getTransaction().commit();
  entityManager.refresh(myRecord); // retrieve generated key

However, I'm trying to use Spring, and the Spring equivalent goes something like this:

public void save(final MyRecord currentItem) {
        final JpaTemplate template = getJpaTemplate();
        template.execute(new JpaCallback() {
 
public Object doInJpa(EntityManager entityManager) throws PersistenceException {
entityManager.persist(currentItem);
return null;
}
        
        });
}

The problem here is that Spring is wrapping the entire method as a transaction, so the record hasn't been committed until after the return and thus no key is retrievable from within the method.

I want the save() method to be totally self-contained, but I'd rather not have to make it work by writing manual transaction code if I can avoid it.

Does anyone know a nice clean solution?