[jboss-user] [JBoss Seam] - Re: Nested conversations and transaction management

[christian.bauer@jboss.com]

OK, last post from me, this is what you need:

- A long-running conversation that is started when the form in 1) is rendered

- A Seam-managed persistence context with @In EntityManager (read the docs) that is bound to that conversation (automatically)

- The conversation should begin with FlushModeType.MANUAL, so that the persistence context does not write to the database until em.flush() is called

- All your screens and popups run inside the same long-running conversation (JSF POSTback propagates the conversation, for opening a new window etc. and propagation during GET use s:link or s:button)

- Use the @In EntityManager to load objects and queue objects for storing (unflushed)

- If you want to cancel the whole thing, end the conversation without flushing the persistence context

- If you want to commit the whole thing, call em.flush() in the request that also ends the conversation

Finally, this is _not_ trivial although there is probably no framework that makes this easier than Seam. For example, I did not even mention the word "transaction", because what the TransactionalSeamPhaseListener is doing is just fine.


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