>
> We do not recommend using a Event Consumer to directly manipulate the Item
> in question by adding Bitstreams or altering its metadata because not only
> is that available Contexts transactional window is closed by the time you've
> reached processing the Event in the consumer, but its difficult to predict
> the behavior or risk of getting the Event System in the state of of an
> infinite event loop because your alterations will in turn, also alter the
> Item and generate new events in the process.
>
Yes, I saw that, that's why I started to use
context().getDBConnection.commit() to avoid infinite event loops.
> Unfortunately, this is the sort of task most folks were hoping the Event
> System would solve in DSpace 1.5. I feel we are attempting to address its
> shortcomings in the DSpace 2.0 roadmap to come up with a solution.
>
That would be great.
> If you do decide to attempt to use the Event System in such a manner as to
> alter the Object in question and update it again, I would recommend using a
> new dspace Context and make sure you can trap the events in some sort of
> conditional check to make sure they should be propagated to through your
> Consumer again.
>
I tried this but I still get the error. I did the following:
Context c = new Context();
ctx.setCurrentUser(context.getCurrentUser());
ctx.setCurrentLocale(context.getCurrentLocale());
I'll look again at the code in the morning to see if I can understand where
the problem lies.
Thanks.
John
>
>
> Sincerely,
> Mark
>
> On Jun 18, 2008, at 4:31 PM, John Preston wrote:
>
> Can someone say whether it is advisable or not to use the new event system
> under 1.5 to add metadata or bitstreams to an item.
>
> I am moving some of my code to event consumers that would add metadata for
> various item types as well as add bitstreams based on bitstreams already
> ingested. However I'm getting an exception when I try to commit these
> additions within the consumer (either the consume, end or finish methods).
> The particular exception is:
>
> java.util.ConcurrentModificationException
> at
> java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
> at java.util.AbstractList$Itr.next(AbstractList.java:343)
> at
> org.dspace.event.BasicDispatcher.dispatch(BasicDispatcher.java:122)
> at org.dspace.core.Context.commit(Context.java:286)
> at
> org.ejamaica.server.dspace.DSpaceInstance.addSaying(DSpaceInstance.java:1906)
> at
> org.ejamaica.server.dspace.DSpaceInstance.updateSaying(DSpaceInstance.java:1060)
> at
> org.ejamaica.server.MyLibraryServiceImpl.myMethod(MyLibraryServiceImpl.java:147)
>
> Just for info. the section in my code that triggers the initial
> context.commit() occurs in DSpaceInstance.java:1906.
>
> If I don't commit after I add some metadata and/or bitstreams then I don't
> get the error, but then the data and bitstreams don't appear. If I even try
> and use the context.getDBConnection().commit(); I get the same exception.
>
> John
>
>
> ~~~~~~~~~~~~~
> Mark R. Diggory - DSpace Developer and Systems Manager
> MIT Libraries, Systems and Technology Services
> Massachusetts Institute of Technology
> Home Page: http://purl.org/net/mdiggory/homepage
>
>
>
>
>
>
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