Hi,

I'm building a desktop application (SWT/JFACE) and I'm a little bit confused about the way I work with sessions. I started using the singleton class from Hibernate reference documentation. Then I realized that I will need something more complex. I tried different things and I realized that I'll probably need help...

The main problem for me is the Unit of Work and its scope.

For example in two different methods:

public void Method1() {
session = HibernateUtil.getSession();
... do some stuff ...
HibernateUtil.closeSession();
}

public void Method2() {
session = HibernateUtil.getSession();
... do some stuff ...
HibernateUtil.closeSession();
}

What if Method1 makes a call to Method2 before closing the session. Method2 will close the session (in singleton pattern of HibernateUtil) and then Method1 will have a problem.

Another solution is to open two sessions for the two Methods. But then I come to "org.hibernate.HibernateException: Illegal attempt to associate a collection with two open sessions".

I could make it maybe if I can find out if an entity is currently associated with an open session. (This is a question on its own.)

If I'm not clear enough (I'm not clear enough for myself) I would be glad to discuss this in more detail.

Please any suggestions would be highly appreciated.

This may help you out:

http://static.springframework.org/sprin ... ml#d0e7576

It is in context to the Spring Framework, but you don't have to know spring to understand it.

Hope this helps.

-Mike

That did helped me out.

I did a little reading and found out that I somehow missed Contextual Sessions in Hibernate. That is what can help me. I will try to implement it in my app. If I have a problem I will write back.

Also if anybody wants to read something about Contextual Sessions these are short and usefull readings:

http://www.hibernate.org/hib_docs/v3/reference/en/html/architecture.html#architecture-current-session
http://blog.hibernate.org/cgi-bin/blosxom.cgi/2005/04/
http://www.hibernate.org/42.html#A5