I would like to be able to set the table name of a class object at runtime. I've gone through the hibernate source code and made some minor changes to see if this is doable. I made a few changes and as a result one can do something like this:

Configuration cfg = new Configuration();
cfg.addClass(Airline.class);
SessionFactory sessionFactory = cfg.buildSessionFactory();
Session session = sessionFactory.openSession();
SessionImpl sessionImpl = (SessionImpl) session;
EntityPersister entityPersister = (EntityPersister)((BatcherImpl)sessionImpl .getBatcher()).getFactory().getPersister("com.sample.Airline");
//in the Airline hbm file, Airline is persisted to a table called

Don't do this it is very non-threadsafe.

It is more acceptable to manipulate the object returned by Configuration.getClassMapping() and have multiple SessionFactories.

What is the downside of using multiple session factories? Will it hog memory if you are dealing with 2000+ users at any given time. What you suggest will require that we have a new session factory for each user depending on choices they make. I imagine it will have a negative impact on overall performance.

I just want to add that it is highly desirable to be able to dynamically specify a table to bind to at the session level and would love to see this feature in hibernate. I have heard that hibernate doesn't allow this for a very, very good reason but no one seems to elaborate on what that good reason is.

The good reason is performance. The ClassPersister is immutable, so that we don't need any synchronized blocks.

And yes, 2000+ session factories will hog memory and impact performance..

p.s. you could consider writing a custom classpersister to solve your problem