Sorry again for the not 100% Tapestry related question, but I got such helpful responses from my last question, and it's clear that there are a lot of people on this list that have already solved these issues that I'm running into (and I'm getting jack from the Hibernate forums ;) )...
I've implemented the "open session in view" pattern in my Tapestry application in the fairly conventional way. I inject a threaded Session via Hivemind using a service factory, and the service factory activates a transaction and creates a ThreadCleanupListener to commit() the transaction and close the session when the thread is done processing the user's request. So far so good. What I'm not sure how to do is handle situations where I may need to inform the user that their transaction failed. For example, let's say I have a typical CRUD application to create new users for my system, and I want to be able to correctly handle the scenario where an administrator attempts to create a new user with a name that is already in use (a primary or unique key violation). I can't simply let the ThreadCleanupListener handle the commit() in this case; if I do this, and an exception is thrown, it is too late to inform the user since the request has already been rendered. The "Open Session in View" page on the Hibernate web site [1] states that a good approach is to use two transactions in one Session. If I took this approach, I would attempt to commit the transaction in my listener method, and catch the exception thrown from the database, and convert this into a validation error which states that the username is already taken. The problem with this is that the Hibernate documentation is quite clear that if any exception occurs, the transaction should be rolled back, and the Session should be closed and discarded. Rolling back is not a problem, but if I close and discard the Session, I'm no longer using "open session in view". I'll have to go to the trouble to initialize any lazy collections or proxies that the view might need before I attempt the commit, otherwise I'll get a LazyInitializationException. But I've read one of the Spring guys saying [2] that it's ok to begin a new transaction on the same Session that has been rolled back, if you're only using it to initialize lazy collections. This would be nice if it were actually true; it would simplify things for me quite a bit. But I hestitate to rely on that, since the Hibernate documentation says otherwise. Can someone with a bit more experience with give me some advice on how to approach this? Thanks in advance... [1] http://www.hibernate.org/43.html [2] http://forum.springframework.org/showpost.php?p=29579&postcount=6 --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
