Re: [eclipselink-users] Questions regarding SessionEventListener and Ent

[James Sutherland <jamesssss@xxxxxxxxx>]

1 - Calling preCommitUnitOfWork in flush does not seem correct, as it is not
a commit.  A pre/postFlushUnitOfWork event would be useful though, please
log an enhancement request for this.  There are also the
pre/postCalculateUnitOfWorkChangeSet events which might be useful.

2 - The UnitOfWorkChangeSet used to commit, will only contains the change
being committed in that write, it will not contain previously flushed
changes.  If an object was new before a flush, then changed, in the
commit/next flush it will not be new.

The UnitOfWork merge will contain the entire change set for the whole
transaction.  The RepeatableWriteUnitOfWork contains a second change set
that include the cumulative changes (cumulativeUOWChangeSet), however there
does not seem to be a get method for this, please log a bug to have one
added, then you can access this change set if you require.



patric-5 wrote:
> 
> Hello everyone,
> 
> I've got two questions regarding the SessionEventListener concept
> and flushing the entity manager (either explizit or implicit).
> 
> 1. Shouldn't RepeatableWriteUnitOfWork.writeChanges() also call the  
> getEventManager().preCommitUnitOfWork()?
> so that a SessionEventListener has a change to intercept this call ?
> Otherwise it is not directly possible to intercept an EntityManager
> flush().
> This is even more difficult if the flush is implicit (e.g. before  
> executing a query)
> 
> 2.
> Case 1:
> Imagine that some managed entities got changed, and a flush() will be  
> (successfully) executed.
> Will the changeset of further flush() calls (or even a transaction  
> commit) contain those entities again, or will they be removed in the  
> changeset which is "delivered" through the SessionEvent?
> 
> Case 2:
> And to how will the changeset look in the following situation:
> 1. a new entity will be persisted
> 2. flush() will be called, changeset contain the entity, marked as "new".
> 3. this entity will now be changed by the application
> 4. flush()/transaction commit will be invoked.
> 5. how does the changeset (in the preCommitUnitOfWork() event) look  
> like? is the entity still marked as "new"?
> 
> Best regards,
> Patric
> 
> 


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