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From Karan Malhi <karan.ma...@gmail.com>
Subject Re: UserObject
Date Fri, 30 Sep 2005 00:14:34 GMT
Hi Craig,

This is assuming that both the beans are on the same jvm
I dont see this kind of a scenario working on the two SSB's on different
JVM's. Correct?

"The UserObject pattern is intended for applications that need to
access some local state that is associated with the persistence
context"

And by persistence context you mean "local persistence context", right?

On 9/29/05, Craig Russell <craig.russell@sun.com> wrote:
>
> Hi Karan,
>
> Yes, this use case is absolutely supported, assuming that transaction
> propagation is in effect.
>
> If there is no transaction propagation, you can still achieve the same
> effect if you pass a "live" object from one bean to another:
>
> class SSBA {
> pm = pmf.getPM();
> SomeState ss = new SomeState(some, state);
> pm.setUserObject(ss);
> Object bean = pm.getObjectById(theID);
> ssbB.B(bean);
> pm.close();
> ...
> }
>
> class SSBB {
> void B(Object bean);
> pm = JDOHelper.getPersistenceManager(bean);
> SomeState ss = (SomeState)pm.getUserObject();
> ss.someMethod();
> }
>
> Craig
>
> From: karan.malhi@gmail.com
> Subject: Re: PersistenceManager UserObject
> Date: September 29, 2005 1:16:52 PM PDT
> To: jdo-dev@db.apache.org
> Reply-To: jdo-dev@db.apache.org, karan.malhi@gmail.com
>
> Hi Michael,
> I am thinking of a scenario where it can be used. Correct me if i am
> wrong.
> lets say a stateless session bean (Container managed transaction), has a
> method
> method A(){
> // get the pm
> pm.setUserObject(new Object());
> B();
> pm.close();
> }
> another session bean has
> method B(){
> //get pm
> pm.getUserObject(); //this should work
> }
> assuming that the same transaction got propagated to B(), should we be
> able
> to get the UserObject, because the second session bean should also get the
> same instance of pm as the first one.
> Let me know if this could be a usecase of get/set User Object
> On 9/29/05, Michael Bouschen <mbo.tech@spree.de> wrote:
>
> Hi Karan,
>
> Hi Craig,
> Thanks.
> What happens to the user object once i close the pm?
>
>
>
> I think nothing will happen. Accoring to the spec a user object is not
> inspected or used in any way by the JDO implementation.
>
> Regards Michael
>
> On 9/29/05, Craig Russell <craig.russell@sun.com> wrote:
>
>
> Hi Karan,
>
> The UserObject pattern is intended for applications that need to
> access some local state that is associated with the persistence
> context. Any persistent object can navigate to its persistence manager
> and access some application-specific data.
>
> This turned out to be very useful in JDO, so much so that users asked
> for finer-grained UserObject information: a Map of UserKey and
> UserValue.
>
> Craig
>
> From: karan.malhi@gmail.com
> Subject: user object with pm
> Date: September 29, 2005 8:24:33 AM PDT
> To: jdo-dev@db.apache.org
> Reply-To: jdo-dev@db.apache.org, karan.malhi@gmail.com
>
> Hi Craig,
> What is the purpose of get/setUserObject in the pm api? What would be
> the
> use-case where i would use these methods?
> --
> Karan Malhi
> --
> Karan Malhi
> Michael Bouschen Tech@Spree Engineering GmbH
> mailto:mbo.tech@spree.de http://www.tech.spree.de/
> Tel.:++49/30/235 520-33 Buelowstr. 66
> Fax.:++49/30/2175 2012 D-10783 Berlin
>
>
>
>
> --
> Karan Malhi
>



--
Karan Malhi

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