[JPA] What is the best strategy to revert an entity after rollback?

Question

Hi,
Let's assume we have the following scenario:
I have instantiated an entity, I have populated it with data and I have sent it to an EJB3 to be persisted. In the beginning, the entity's ID is null. So, in the EJB3 we might have something like the following code:
    @PersistenceContext(unitName="someUnit") private EntityManager em;
    @Resource private SessionContext ctx;
try {
    em.persist(theEntity);       // (L1)
    em.flush();                  // (L2)
    ... >>> call a stored procedure <<< ...
    if (resultOfTheStoredProcedureIndicatesFailure)
        ctx.setRollbackOnly();   // (L3)
} catch(Throwable t) {
    ctx.setRollbackOnly();       // (L4)
    ... >>> do whatever else is necessary <<< ...
}Ok, on line (L1) the value for the @Id column gets selected from the sequence and assigned to the appropriate entity field.
Line (L2) flushes the data to the database, so that the stored procedure will see it.
Then the stored procedure is called, it fails for some reason and on line (L3) we indicate that we wish to rollback the transaction. And it gets rolled back.
So far, so good.
But after the rollback, the entity already has an ID value assigned to its @Id field. And, if optimistic locking is used (that is, @Version), then the version will be assigned too.
So, is there a recommended way to revert the entity back to its original pristine state? Is it possible that the new "dirty" entity may cause problems along the way, if we retry the operation? I checked both with persist() and merge() on the "dirty" entity and they both seemed to work, albeit with additional DB round-trips.
Best regards,
Bisser

Answer 1

Hello,
For calendar and contacts, there is this:
http://supportforums.blackberry.com/t5/BlackBerry-Q10/How-To-OTA-Sync-BB10-and-non-BES-Outlook-Overv...
With that, I actually keep all of the following in sync:
Two instances of Desktop Outlook (2007 and 2010)
Z10
PlayBook
Outlook.com
And, before I decommissioned it, also an Android device. Any device that can synchronize with Outlook.com can use this solution to keep in sync for calendar and contacts. You, of course, need to not use solely local contacts and calendar but instead keep them synchronizing with Outlook.com.
For the other things you mention, I know of no solutions other than backup/restore...but I do not recall if LINK offers the selective method for those.
Good luck!
Occam's Razor nearly always applies when troubleshooting technology issues!
If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.
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