I want to use a HibernateSession to store and retrieve my data.

Question one: does opening and closing a Hibernate session 10 times introduce a drastic overhead compared to opening and closing it once? (In this scenario there can be a good few hundred concurrent users)

If it does, how can I use one session for all portlets?

Ex:

HibernateSession gets opened();
[Portlet1: processAction()]
Portlet2: doView()
Portlet1: doView()
Portlet3: doView()
....
HibernateSession gets closed();

To put it another way:

1. How can I run code BEFORE any portlet (processAction or doView) method gets called?

2. How can I run code AFTER all (processAction and doView) methods have been called?


Thanks,
John