Transaction Resuming

[punnooser]

Hi,

I am using a JTATransactionManager to manage, create, suspend my transactions. I have a method, Method A, that calls another method, Method B, which itself calls another method, Method C. Method A creates a transaction, and Method B suspends the transaction while it is running. I want Method C to resume the same transaction that B suspended. Is this possible? Right now, Method C is forced to create a new transaction, because it does not see the suspended transaction. Or, is it that while Method B is active, the suspended transaction cannot be resumed. (We are using TransactionProxyFactoryBean to intercept our method calls and uses the transactions)

Roshan

[Costin Leau]

You should consult your JTA TM documentation - AFAIK, Weblogic has a very good implementation that handles this issue (for that you should use the WebLogicJtaTransactionManager).

[punnooser]

Hi,

I am using the WebLogicJtaTransactionManager, however I don't think it has anything to do with resuming transactions. I will look at the documentation though. However, I thought that if Method C is set at PROPAGATION_REQUIRED, then it should pick up the suspended transaction and resume it?

Roshan

[Costin Leau]

I think you can find more details on the dev mailing list.

[trisberg]

I don't think it's possible using Spring or EJB transactions. You are basically looking for a PROPAGATION_REQUIRES_PREVIOUS transaction setting.

What's your use case for this reuirement?

I think you will have to break your code into finer grained methods like this.

A REQUIRED
|
v
B SUPPORTS
|
|--> B1 NOT_SUPPORTED
|-> B2 SUPPORTS --------------> C SUPPORTS
'-> B3 NOT_SUPPORTED

[punnooser]

Well, what I am trying to do is work against two databases. For one database, we cannot use transacations, but we can use transacations against the second one. We are trying to stream data from one into the other. Now we have Database1 and Database2. And we are trying to stream data from Dbase1 to Dbase2. So we have a Dbase1DAO that takes an InputStream from DBase1 and streams it into Dbase2. We have that working, however all this happens in one function because we do not want to handle the ResultSet returned from DBase1 outside of its DAO. So from what you said before this is the sort of pseudo-code we need to do:

ExecutionController:

Call DBase1DAO.streamData(): //PROPAGATION_REQUIRED
--inputStream = DBase1DAO.getInputStream() //Suspend Transaction
--Call DBase1DAO.connectStream(inputStream) //Resume Trasaction
--Close connection to DBase1 and DBase2

Now the problem with this code is that the TransactionInterceptor does not change the transactions between function calls inside the same class. Is there some way that I can cause the Interceptor to intercept the call to getInputStream() and attach a PROPAGATION_NOT_SUPPORTED to it?

Thanks!

[trisberg]

In that case, you must have two datasources - set it up so that one participates in the transaction and one that does not. So, you should be able to run the whole thing within a transaction, one of the databases are just not participating in the transaction.