Hi All,
I'm having some fun with Optimistic locking. Specifically, I'm trying to
delete a series of objects contained in a collection, and getting the
following error.
org.odmg.LockNotGrantedException: Object has been modified by someone
else
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)
at
nz.ac.auckland.markit.netbeans.modules.property.propertyviews.MarkingMap
View.commitTransaction(MarkingMapView.java:432)
Now, I'm the only one using the db. I get the markingMap from the
assessment, deep clone it (setting ID's to null), and let the users
adjust it.
When they've finished, I delete the entries in the existing markingMap
for the assessment, then add the new entries to the db in their place.
>From debugging and commenting out bits, adding the new entries works,
but deleting the old ones doesn't. The existing MarkingMap entry objects
aren't changed anywhere before I attempt to delete them.
MarkingMap is a little special. Its basically a wrapped list of
MarkeeData objects. And we're referring to it as part of the Assessment
Object via the markingMap::list syntax. This has worked fine before we
were using Optimistic Locking on it, so I'm not sure what's going on now
:)
In OJB.properties, ImplicitLocking is set to false and LockAssociations
is set to read.
Thanks for your help,
Robert
Relevant bits of the repository:
<!-- nz.ac.auckland.markit.core.Assessment -->
<class-descriptor class="nz.ac.auckland.markit.core.Assessment"
table="Assessment">
<field-descriptor name="id" column="id" jdbc-type="INTEGER"
primarykey="true" autoincrement="true"/>
<field-descriptor name="ojbVersion" column="ojb_version"
jdbc-type="INTEGER" locking="true"/>
....
<collection-descriptor
name="markingMap::list"
element-class-ref="nz.ac.auckland.markit.core.MarkeeData"
collection-class="nz.ac.auckland.markit.core.TypedSet"
auto-retrieve="true"
auto-update="false"
>
<inverse-foreignkey field-ref="id_Assessment"/>
<orderby name="listIndex" sort="ASC"/>
</collection-descriptor>
</class-descriptor>
<!-- nz.ac.auckland.markit.core.MarkeeData -->
<class-descriptor class="nz.ac.auckland.markit.core.MarkeeData"
table="MarkeeData">
<field-descriptor name="id" column="id" jdbc-type="INTEGER"
primarykey="true" autoincrement="true"/>
<field-descriptor name="ojbVersion" column="ojb_version"
jdbc-type="INTEGER" locking="true"/>
<field-descriptor name="id_Assessment" column="id_Assessment"
jdbc-type="INTEGER"/>
...
<reference-descriptor name="assessment"
class-ref="nz.ac.auckland.markit.core.Assessment">
<foreignkey field-ref="id_Assessment"/>
</reference-descriptor>
</class-descriptor>
And the original code:
...
Transaction tx =
PersistenceManager.getInstance().getODMG().newTransaction();
Database db = PersistenceManager.getInstance().getOdmgDb();
try{
//Make the new marking map (currMarkingMap) persistent for
currAssessment
tx.begin();
tx.lock(currAssessment, Transaction.WRITE);
// delete the old marking map entries
for (Iterator iter =
currAssessment.getMarkingMap().getData().listIterator();
iter.hasNext();) {
MarkeeData md = (MarkeeData)iter.next();
db.deletePersistent(md);
iter.remove();
}
// add the new entries
currMarkingMap.setAssessment(currAssessment); // set
all the new entry's assessments to point
// to currentAssessment
for(Iterator iter = currMarkingMap.getData().listIterator();
iter.hasNext();) {
MarkeeData md = (MarkeeData)iter.next();
tx.lock(md, Transaction.WRITE);
}
currAssessment.setMarkingMap(currMarkingMap); // set the
assessment's marking map to point here.
tx.commit();
}catch(Exception e){
if (tx.isOpen())
tx.abort();
ErrorManager.getDefault().notify(e);
}
...
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