Standalone spring app XA transactions with IBM MQ and Oracle as resources - spring

Question

I am in the process of developing a stand alone Apache camel application (not running on a J2EE container).
This apps needs to be capable of routing messages from an IBM MQ queue manager to an Oracle database in a distributed transaction.
My google searches pretty much took me to a few places but none of those were able to give me some good clues about how to put everything together.
This link below was the closest to what I need but unfortunately it is not cler enough to put me on the right path.
IBM MQManager as XA Transaction Manager with Spring-jms and Spring-tx
Thank you in advance for your inputs.

Answer 1

You will need to use a JTA TransactionManager, but since not being in a j2ee container i would sugest to use Atomikos.
https://github.com/camelinaction/camelinaction/tree/master/chapter9/xa
My route which is working with IBM MQ -> Oracle Database, in an J2EE yes but still should be working with Atomikos setup. I would say this isn't the proper way to to it, but it's the only way I managed to get it working - working well enough for my use case.
from(inQueue)
.transacted()
.setHeader("storeData", constant(false))
.to("direct:a")
.choice().when(header("storeData").isEqualTo(false)) // if this is true the database calls are 'successful'
.log("Sending message to errorQueue")
.to(errorQueue)
;
StoreDataBean storeDataBean = new StoreDataBean();
from("direct:a")
.onException(Exception.class).handled(false).log("Rollbacking database changes").markRollbackOnlyLast().end()
.transacted("PROPAGATION_REQUIRES_NEW")
.bean(storeDataBean) //storeData sets the header storeData to true if no SQLException or other exceptions are thrown
.end()
;
The commit are handled by the transaction manager, so if I actually get an error with the database commit, it should rollback the message.
Next problem that I have had with rollbacking messages is that I can't set the deadLetterQueue, as you can with ActiveMQ. So it rolls back to the incoming queue. Therefore I actually handle the database transaction as I do, it is in a new transaction, which is rollbacked in case of a normal SQLException when calling the database.
I wished this worked:
from(inQueue)
.onException(Exception.class).to(errorQueue).markRollbackOnly().end()
.bean(storeDataBean)
.end()
I have posted about this in the community forums but no answers at all.