>1. Should our
EntityManagerImpl wrap a client-session instead of a server session to better
handle the isolated client session's cache lifecycle matching that of the
EntityManager? If we need a server session we can always get it through
getParent()
The
ClientSession is released after JTA transction is completed, therefore we
can't keep ClientSession for
the lifetime EntityManagerImpl.
[Doug Clarke] Why is
this? If I decide I want to use just the shared cache it continues to function
across multiple EntityManager and across multiple transactions within those
entity managers. Why is it then why I decide I want an isolated cache would
that cache not live for the lifespan of my EntityManager across zero or
more transactions. I can see how the UnitOfWork used in the EntityManager
would be released after the commit.
Note: We would need to discuss how
EntityManager.clear() would behave with respect to the client sessions's
isolated cache versus the transactional cache and an extended persistence
context.
>2. How can we
address proxy authentication through JPA? We need to change how we create the
client session within the EntityManagerImpl and thus the lifecycle of the
client session is important to this discussion. See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=219434
We
should pass proxy authentication properties to createEntityManager
method, then use thiese properties in to create first ClientSession, then
RepeatableWriteUOW in getActivePersistenceContext method.
>3. Does anyone
have an idea of how I could work-around our current implementation limitations
to make proxy authentication work through our current JPA implementation in
EclipseLink?
It *might*
be possible to do something probably using thread variables.
[Doug Clarke] OK,
thanks. I'll try a few things
out.
----- Original Message -----
Sent: Wednesday, February 20, 2008 8:37
AM
Subject: [eclipselink-dev]
EntityManager usage of ClientSession
Developers,
On the TopLink
forum
there is a customer trying to use proxy authentication. Our
documentation and a similar thread on the JDeveloper
forum show the usage of proxy authentication using a
SessionEventListener and a custom call to
Server.acquireClientSession(db-login). Using this within JPA is proving
challenging. The SessionEventListener can be easily introduced using a
persistence unit property but addressing the proxy credentials is more
challenging:
Login login = (Login)serverSession.getLogin().clone();
login.setProperty("proxytype", Integer.toString(OracleConnection.PROXYTYPE_USER_NAME));
login.setProperty(OracleConnection.PROXY_USER_NAME, "hr");
ConnectionPolicy connectionPolicy = new ConnectionPolicy(login);
// for vpd support connectionPolicy.setShouldUseExclusiveConnection(true);
clientSession = serverSession.acquireClientSession(connectionPolicy);
I took a quick
look through our implementation of EntityManager and we have one case where
we acquire a client session in the process of acquiring a UnitOfWork but in
most cases we simply acquire the UnitOfWork from the server session. I know
this internally results in a client session but it does feel weird. I would
have expected us to acquire a client session and hold it in the
EntityManager (possibly during construction) and then acquire
repeatable-read UnitOfWork or non-synchonized UnitOfWork as needed form the
client session. This would allow the isolated client session, when used, to
have a life-cycle equivalent to that of the
EntityManager.
I guess I have a
few questions:
1. Should our
EntityManagerImpl wrap a client-session instead of a server session to
better handle the isolated client session's cache lifecycle matching that of
the EntityManager? If we need a server session we can always get it through
getParent()
2. How can we
address proxy authentication through JPA? We need to change how we create
the client session within the EntityManagerImpl and thus the lifecycle of
the client session is important to this discussion. See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=219434
3. Does anyone
have an idea of how I could work-around our current implementation
limitations to make proxy authentication work through our current JPA
implementation in EclipseLink?
Cheers,
Doug
Doug Clarke
Director of
Product Management, Oracle TopLink
Oracle Server
Technologies
45 O'Connor, Suite 4000 | Ottawa, ON K1P
1A4 Canada
+1 613 288
4617
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