This rings a bit of a bell with me. We made our first big release with
Cayenne 3.0 a couple of weeks ago (it went well, thank you) and saw a
similar-sounding problem. It happened only intermittently and only on our
production server. We could never reproduce it on our test server, let
alone in a debugger.
We had an object stored in the session. Our editor-page initialization code
got the object and then the value of its to-one relationship. This related
object would occasionally be null.
StoryDetail object from session ---to-one---> Story (occasionally
null)
We couldn't pin down how to reproduce it. (The user it kept happening too
works very remotely.) My guess was some kind of garbage collection. The
user would enter a lot of text for several minutes and then save/refresh the
page and get the NPE. The other hint was that the same code had never had a
problem in two years with Cayenne 2. On the other hand, I was unable to
reproduce it by adding explicit garbage collection calls so my guess could
be off base.
I worked around it by refetching the list of StoryDetails, with a prefetch
on Story, so that the desired Story object would always be freshly fetched.
On Tue, Jan 5, 2010 at 3:31 PM, Andrus Adamchik <andru..bjectstyle.org>wrote:
> On the surface looks like some (de)serialization issue. Although that
> doesn't make much sense, as RelationshipFault.relationshipOwner is not
> transient and can't be reset to null easily. The best bet is to run this in
> debugger to get a better picture of what's going on with your objects.
>
> Andrus
>
>
> On Jan 5, 2010, at 10:13 PM, Marek Šabo wrote:
>
>> Hi all,
>>
>> is there any way that a dataobject could expire? I mean i'm storing user's
>> settings dataobject in session and after a while, say max 5 min. when I try
>> to submit a form that binds this data as foreign key I got a nullpointer
>> exception from setting up that relationship. I think it does't expire in
>> session because I'm still logged in and only way is to logout and login back
>> to have the setting reloaded from database. Appending end of stacktrace:
>>
>> at
>> org.apache.cayenne.util.RelationshipFault.isTransientParent(RelationshipFault.java:70)
>> at
>> org.apache.cayenne.util.PersistentObjectList.isFault(PersistentObjectList.java:75)
>> at
>> org.apache.cayenne.util.PersistentObjectList.add(PersistentObjectList.java:125)
>> at
>> org.apache.cayenne.CayenneDataObject.addToManyTarget(CayenneDataObject.java:282)
>> at
>> org.apache.cayenne.CayenneDataObject.setReverseRelationship(CayenneDataObject.java:364)
>> at
>> org.apache.cayenne.CayenneDataObject.setToOneTarget(CayenneDataObject.java:315)
>>
>> Thanks for any ideas,
>>
>> Regards
>>
>> --
>> Marek Šabo
>>
>
>
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