Let say before this feature I removed an item from a private collection,
but forgot to set to null other(s) reference to the item. 
In my next unit of work, when I query and EclipseLink do not find the
object that the stale reference point to, it put a null in it.
So with this new feature, when I remove an item from a private
collection, and still have somewhere another reference to the item, no
delete will occur to DB.
Is it good understanding of the old and new functionality?
-----Original Message-----
From: christopher delahunt [mailto:christopher.delahunt@xxxxxxxxxx] 
Sent: Thursday, May 21, 2009 9:31 AM
To: Dev mailing list for Eclipse Persistence Services; Sebastien Tardif
Subject: Re: [eclipselink-dev] FYI:
uow.discoverUnregisteredNewObjectsisinefficient and with side effect
Hello Sebastien,
This should only affect new objects registered via a privately owned 
relationship. De-referencing the objects from the relationship will mean
they are removed from the cache (rather than being inserted anyway). The
wording on the method is correct, and removing it from the 
privateOwnedObjects only means the object is still referenced via the 
original privately owned relationship and so should be inserted. If it 
is left on the list, it is eventually unregistered.
What exactly are you experiencing, and what is the relationship to the 
objects that are expected to be deleted?
Best Regards,
Chris
Sebastien Tardif wrote:
  
I just saw something bigger for side effect in 
discoverUnregisteredNewObjects than setUnregisteredExistingObjects.
Some of our use cases are randomly failing, and involve almost just 
TopLink code.
Other use case involving delete do not delete.
New code that have nothing to do with discoverUnregisteredNewObjects 
have been recently added to the method under revision 3676.
From the JavaDoc of method removePrivateOwnedObject that seems a good 
candidate for explaining our delete use case failing. The code seems 
to systematically remove object from privateOwnedObjects when ever 
it's private owned.
When an object (which is referenced) is removed from the 
privateOwnedObjects Map, it is no longer considered for removal from 
ChangeSets and the UnitOfWork identitymap.
public void iterateReferenceObjectForMapping(Object referenceObject, 
DatabaseMapping mapping) {
super.iterateReferenceObjectForMapping(referenceObject, mapping);
if (mapping.isCandidateForPrivateOwnedRemoval()) {
removePrivateOwnedObject(mapping, referenceObject);
}
}
public boolean isCandidateForPrivateOwnedRemoval() {
return isPrivateOwned();
}
public void removePrivateOwnedObject(DatabaseMapping mapping, Object 
privateOwnedObject) {
if (this.privateOwnedObjects != null) {
Set objectsForMapping = this.privateOwnedObjects.get(mapping);
if (objectsForMapping != null){
objectsForMapping.remove(privateOwnedObject);
if (objectsForMapping.isEmpty()) {
this.privateOwnedObjects.remove(mapping);
}
}
}
}
    
------------------------------------------------------------------------
  
*From:* eclipselink-dev-bounces@xxxxxxxxxxx 
[mailto:eclipselink-dev-bounces@xxxxxxxxxxx] *On Behalf Of *Sebastien 
Tardif
*Sent:* Wednesday, May 20, 2009 10:35 AM
*To:* Dev mailing list for Eclipse Persistence Services
*Subject:* RE: [eclipselink-dev] FYI: 
uow.discoverUnregisteredNewObjectsisinefficient and with side effect
The method getBackkupClone() has two lines doing the cloning, maybe 
you know for sure that these lines are never reached.
- return descriptor.getObjectBuilder().buildNewInstance();
- backupClone = descriptor.getObjectBuilder().buildNewInstance();
I still don't like the side effect of the method 
discoverUnregisteredNewObjects, could you provide one without side
    
effect?
  
It's kind of very useful to be able to find the list of 
knownNewObjects and unregisteredExistingObjects.
    
------------------------------------------------------------------------
  
*From:* eclipselink-dev-bounces@xxxxxxxxxxx 
[mailto:eclipselink-dev-bounces@xxxxxxxxxxx] *On Behalf Of *Gordon
    
Yorke
  
*Sent:* Wednesday, May 20, 2009 10:26 AM
*To:* Dev mailing list for Eclipse Persistence Services
*Subject:* Re: [eclipselink-dev] FYI: 
uow.discoverUnregisteredNewObjects isinefficient and with side effect
getBackupClone() does not actually build anything, it just looks for 
the backupClone. It is just a validation step and has not been added 
but moved out of the "normal" processing stream to improve performance
    
  
and efficiency.
--Gordon
Sebastien Tardif wrote:
FYI: uow.discoverUnregisteredNewObjects is inefficient and with side 
effect
/**
* INTERNAL:
* Traverse the object to find references to objects not registered in 
this unit of work.
*/
*public* *void* discoverUnregisteredNewObjects(Map clones, *final* Map
    
  
knownNewObjects, *final* Map unregisteredExistingObjects, Map 
visitedObjects) {
The JavaDoc and signature seem to convey that the only change will be 
to populate the Maps passed as parameters.
* *
*The inefficiency is that in revision 2794 this line has been added:*
* *
getBackupClone(object, getCurrentDescriptor());
We see that we ignore the return value, and we can guess that building
    
  
a clone is not the cheaper operation.
Method discoverUnregisteredNewObjects end-up modifying the UOW by 
doing this:
    
setUnregisteredExistingObjects(unregisteredExistingObjects);
  
The list of unregisteredExistingObjects will be returned anyway, so 
that doesn't seem to be the responsibility of 
discoverUnregisteredNewObjects to apply some logic with the result.
 
 
 
    
------------------------------------------------------------------------
  
 
 
 
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