Re: NullPointerException only after first call to batchFetchRelationship

I also do a lot of batchFetchRelationship and have not seen this. 
Yet.  We don't often use child EC's so that may explain it.

Strange, hard to reproduce, errors like this can be the result of an 
editing context processing notifications sent by another editing 
context.  Tracking this down can be very difficult.  I looked at the 
stack trace that Kaj posted but did not see any evidence of this.  It 
looks like something in EODatabaseContext is hosed.

Chuck


Kaj Hejer wrote:

> At 08:57 -0400 17-08-03, Lenny Marks wrote:
> 
>> I have a direct action to render all information for a specified
>> 'Manuscript' in our database. The rendering of this page traces deep into
>> the manuscript's relationships and was slow so I was attempting to use
>> EODatabaseContext.batchFetchRelationship to limit the hits to the
>> database. I added a method batchFetchManuscriptEvents(the root of the 
>> deep
>> relationships) to my Manuscript EOEnterpriseObject class. I was hoping
>> that the application could call this in anticipation of its particular
>> display needs. The method would batchFetch all the relationships so that
>> by the time the WOComponent was generating its response, all the
>> relationships would have already been faulted. This actually worked, but
>> only the first time the method is invoked on a Manuscript instance within
>> a single EOF stack. The first time I access the direct action for a
>> manuscript, it works, but if I hit reload I get the exception below.
>>
>> Any clues would be greatly appreciated!
>>
>> -Lenny Marks
>>
>> <ManView>[2003-08-17 07:49:16 EDT] <Thread-6>
>> java.lang.NullPointerException
>>         at
>> com.webobjects.eocontrol._EOMutableKnownKeyDictionary.<init>(_EOMutableKnownKeyDictionary.java:90) 
>>
>>         at
>> com.webobjects.eoaccess.EORelationship._foreignKeyForSourceRow(EORelationship.java:1094) 
>>
> 
> 
> 
> 
> 
> Hi!
> 
> I now saw the same exception when using prefetching.
> 
> The stacktrace and the method where I get this exception can be found at 
> http://folk.uio.no/kajh/tmp/wo20031214.txt
> 
> Has anybody else here seen this?
> 
> The ec I use here is a childEC of session.defaulteditingContext and this 
> childEC has been locked.
> 
> I have only managed to reproduced this issue two times while testing 
> this application for about an hour, so it seems that it does not appear 
> so very often.
> 
> 
> -Kaj :)
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-- 

Chuck Hill                                 [email protected]
Global Village Consulting Inc.             http://www.global-village.net

Progress is the mother of all problems.
- G. K. Chesterton