Spring transaction integration

[Dain Sundstrom]

I've been looking at integrating with Spring's  
PlatformTransactionManager (PTM) when embedded in Spring.   
Specifically, I'd like to use the PTM instead of a JTA  
TransactionManager in the EJB containers.  After a lot of digging and  
hacking, I think we can abstract away direct JTA TransactionManager  
usage from the containers without out too much work.  Currently,  
OpenEJB uses the TransactionPolicy abstraction to handle container and  
bean managed transactions.  This abstraction is very similar to the  
Spring TransactionStatus abstraction, so I think I this will be the  
key place to slip-in Spring.  My general idea is to expand the current  
TransactionPolicy interface to include a few extra methods that the  
container need (e.g., registerSynchronization, get/putResource) so  
they no longer use a JTA TransactionManager directly.  Then I'll add a  
factory, so the TransactionPolicy can be replaced with a Spring based  
implementation.  Well that's the plan at least, we'll see how it works  
out :)

-dain