I'm having some problems around the use of implicit recursive locking in ODMG.
I am using 0.9.8, though I had the same problems in 0.9.7. I'm using
isolation-level="read-uncommitted", ImplicitLocking=true, and
LockAssociations=WRITE.
The first problem is that I sometimes get a ConcurrentModificationException in
commit:
java.util.ConcurrentModificationException
at
java.util.AbstractList$Itr.checkForComodification(AbstractList.java:440)
at java.util.AbstractList$Itr.next(AbstractList.java:413)
at org.apache.ojb.odmg.ObjectEnvelopeTable.commit(Unknown Source)
at org.apache.ojb.odmg.TransactionImpl.doCommitOnObjects(Unknown Source)
at org.apache.ojb.odmg.TransactionImpl.prepare(Unknown Source)
at org.apache.ojb.odmg.TransactionImpl.commit(Unknown Source)
I think this is happening because I've explicitly locked an object which is
reachable from another object which also has been locked to the transaction,
i.e.:
tx.lock(anObject, tx.WRITE);
tx.lock(anObject.getRelationship().getAnotherRelationship());
A second, presumably related problem is that ODMG doesn't seem to allow cycles
in my instance graph - i.e., I have a Study object which has a collection of
Contacts, and each Contact points back to its Study. When I try to lock a
Study, OJB goes off and locks each Contact, and in turn tries to lock each
Contact's study - which consistently fails. I confess that I haven't verified
this in 0.9.8, but it was very consistent in 0.9.7.
I assume that there's something fundamental that I'm misunderstanding. Can
anybody shed some light on this?
thanks in advance,
-steve
Steve Clark
Technology Applications Team
Natural Resources Research Center/USGS
[EMAIL PROTECTED]
(970)226-9291
--
To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]>
For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
