Ive looked over the Seam docs and examples, and dont quite see how you would implement the editing of a db backed entity. I understand editing a new (transient) one, but dont see how the incremental changes to the persistent one wont get persisted untill you are done.

Given :

Statefull bean gets created
Extened persistence context gets injected
Methods are called to locate the entity to be edited which gets stored in the bean and exposed.
User interacts with the system and modifies the entity.

>>What happens when a transactional method (say to go lookup some other data that might be needed while editing) is called on that statful bean, wont the entity get flushed and commited since its dirty?


This doesnt relate only to Seam, the same condition can occur anytime you modify an entity outside of a transactional method, then call a transaction method.

Is there someway to demark a method as being readonly in reguards to the transaction such that it will only read data and never cause a commit?

Or should those methods be defined as REQUIRES_NEW instead of REQUIRED? Does requires new use a different EntityManager (ie Hibernate session)? If so wont there be issues with the original entity that is to be saved at some point referencing db backed entities loaded from a different session?

huh??

oh i get it

You need to use @FlushMode(NEVER) or, mark the methods NOT_SUPPORTED.

That way the methods that i consider readonly never cause a flush.

On the NOT_SUPPORTED option wouldnt that mean that the EM wouldnt have a current transaction and therefore cant be used or am I missing something?


BTW Seam looks pretty dang cool, addresses exactly what i been fighting with in jsf. Only problem is Im stuck on H2.1 and J1.4 =(

You can run queries outside of tx context in EJB3.

But actually, I don't think this is the best solution really, since you wont be able to call persist() to save new objects.

FlushMode.NEVER is the best solution.

BTW, HB2.1 and JDK5 have been out for over 6 months now. Time to upgrade.

I know, but the powers that be dont like change. Especially if its going to affect the timeline =)


Thanks for the help.

Year, that might speed up your project, safe choice not to try ;-p