reusing sessions across multiple method calls

[Kaarthik Sivashanmugam]

I am using Hibernate and Spring in my project. My DAO has several methods like
getEntity()
getRelatedEntities()
etc.

Since the related entities are loaded lazily, I want to reuse the session across multiple method calls. I want to make sure that getHibernateTemplate() in all the methods in my DAO use the same session instead of creating one for each method call. I have tried using "HibernateTransactionManager" with "LocalSessionFactory"; but whenever I make a call to the DAO, it throws an exception that says "no session is bound or session closed". Do I have to explicitly get a session in the DAO and bind it to the current thread of DAO, so that the session is retained across all method calls in that DAO ?

Also, the use of SessionFactoryUtils.getSession() method is not very clear to me. When and where can it be used ?

Responses are much appreciated.

[Lasse Koskela]

Are you closing the Hibernate Session object somewhere manually?
Could you post a code snippet from your DAO implementation class?

[Kaarthik Sivashanmugam]

Thanks for the quick response.

I am not explicitly opening or closing sessions. I just use getHibernateTemplate(). I think Spring opens and closes session for every method call.

A typical method in my DAO would look like:

public void saveEntities(final List<Entity> entities) {
getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws net.sf.hibernate.HibernateException, java.sql.SQLException {
for (Entity entity : entities) {
session.saveOrUpdate(entity);
}
return null;
}
});
 
}

I am interested in reusing the same session object across multiple doInHibernate() calls.

I also tried using a HibernateTemplate object as a instance variable in my DAO and use the instance variable (and hence the same template) to carry out multiple methods; that didnt seem to help either. A new session is used in every method call.
[ February 22, 2005: Message edited by: Kaarthik Sivashanmugam ]