Access data sources supporting Tuxedo

Question

WLS 5.1 states that it does not support two-phase commit.
In fact, if I try to establish two connections to different Oracle
databases within the same entity bean or session bean within a
transactional context then an exception is thrown.
I need to perform updates to two different resources, the first is an
Oracle database and the second is a Clarify CRM database.
The problem is getting the updates to both resources done atomically.
The Oracle database has a layer of EJB's and will run inside WebLogic.
The Clarify system only comes with a Java Bean interface (not an EJB
interface).
Obviously, at some point a connection needs to be established to the
underlying Oracle Clarify database and I suspect that the Java Bean
interface that Clarify provides will perform any transactional stuff per
method call. Although we may be able to detect Clarify problems through
exceptions thrown from the Java Bean methods, presumably for each
successful Java Bean method call the underlying data source changes
associated with it will be committed. Any subsequent Java Bean method
call that fails can too be detected but we have no way to roll back the
changes made in the previous method calls. This is obviously a typically
transaction based problem.
So, Clarify supports BEA Tuxedo, presumably for this purpose. Perhaps
someone can confirm, but I think that BEA Jolt provides a Java API to
BEA Tuxedo. Is this the currently recommended way to communicate with
Tuxedo? And does Jolt simply provide the equivalent XA methods such as
transaction start, prepare, commit methods etc?
I mentioned at the start that an exception will be thrown if an attempt
is made to open more than one database connection. Presumably, the
container will not be able to detect this if the connection is retrieved
in an independent Java class that is not part of the EJB? this is
important as BEA Jolt or the underlying Java Bean classes must at some
point establish a connection.
If Jolt provides this type of interface then presumable I could have a
stateless session bean that updates the first Oracle data source through
the EJB's and then simply starts a transaction using Jolt, then applies
the clarify changes using the Java Beans and then can use the two-phase
commit capabilities of Tuxedo to 'prepare' the Clarify changes. If the
prepare fails then a system exception will be thrown to rollback the
changes to the first data source, otherwise Jolt will be used to tell
Tuxedo to commit the changes and then the first data source will be
committed when the session bean method completes.
One drawback that I can see is that the transactional calls to Jolt will
be hardcoded in the beans and not controlled by transactional
demaraction in the deployment descriptors so we would need to be careful
when the transactional boundaries changes in the deployment descriptor.
I can't see how Weblogic 6.0 can assist us here as we don't have an EJB
intterface to Clarify.
How does the J2EE Connector stuff fit into this?
Anyone interfaced with Clarify through Jolt/Tuxedo - is the perfromance
adequate?
Many thanks in advance

Answer 1

Hi,
You can also have a look at Metalink Note:150766.1 :- Subject:      How to Access a JDBC Data Source From OC4J Using a JNDI Lookup
Regards,
Sandeep