Question regarding metadata handling in ojb 1.0.4

Hi,

I am trying to find some information regarding metadata merging in the following scenario:

We have a base application with some classes, db tables and a repository_user.xml that describes the mapping.
Lets say we have a base class BasePersistentClassA and some classes that are based which are included as extent classes in the xml file.
This application is running.

No we develop an optional plugin with a class PluginPersistentClassB that is based on BasePersistentClassA of the application.
I can now write an additional repository.xml and merge it with:

    MetadataManager mm = MetadataManager.getInstance();
    DescriptorRepository dr = mm.readDescriptorRepository("my/additional/plugin_repository.xml");
    mm.mergeDescriptorRepository(dr);

However I am failing to get the correct contents regarding the extent-class definitions of the base class. 
I tried to include the following to plugin_repository.xml:

<class-descriptor
    class="BasePersistentClassA "
>
    <extent-class class-ref="PluginPersistentClassB"/>
</class-descriptor>

<class-descriptor
    class="PluginPersistentClassB "
    table="MyTable"
>
...
</class-descriptor>

Something is strange, as the following code fragment does not delete anything at the first broker.deleteByQuery() and fails at the second one:

    Criteria crit = new Criteria();
    crit.addNotEqualTo("ojbConcreteClass",BaseApplicationClassX.class.getName());
    Query q = QueryFactory.newQuery(Transaction.class,crit);
    broker.deleteByQuery(q);

    // SELECT DISTINCT ACC_TAID FROM ACC_TA
    ReportQueryByCriteria subquery = new ReportQueryByCriteria(BasePersistentClassA .class,null);
    subquery.setAttributes(new String[] { "id" });
    subquery.setDistinct(true);
    
    Criteria crit = new Criteria();
    crit.addNotIn("externalID",subquery);
    Query q = QueryFactory.newQuery(Another.class,crit);
    broker.deleteByQuery(q);

It seems that the extent definitions from dr are not merged and even corrupt the existing definitions of the application, as trying to access all classes from the database results in an NullPointerException:

2007.07.26 17:40:33,375 [0/ServiceRequestDispatcher-P=3/T=7-running:1/1/1] INFO  cleardb: start
java.lang.NullPointerException
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement$TableAlias.hashCode(Unknown Source)
	at java.util.HashMap.hash(Unknown Source)
	at java.util.HashMap.put(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.splitCriteria(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.<init>(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlSelectStatement.<init>(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.getSubQuerySQL(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendSubQuery(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendParameter(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendInCriteria(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendCriteria(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendSQLClause(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.asSQLStatement(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendClause(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.appendWhereClause(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlDeleteByQuery.buildStatement(Unknown Source)
	at org.apache.ojb.broker.accesslayer.sql.SqlQueryStatement.getStatement(Unknown Source)
	at org.apache.ojb.broker.accesslayer.JdbcAccessImpl.executeDelete(Unknown Source)
	at org.apache.ojb.broker.core.PersistenceBrokerImpl.deleteByQuery(Unknown Source)
	at org.apache.ojb.broker.core.PersistenceBrokerImpl.deleteByQuery(Unknown Source)
	at org.apache.ojb.broker.core.DelegatingPersistenceBroker.deleteByQuery(Unknown Source)
	at org.apache.ojb.broker.core.DelegatingPersistenceBroker.deleteByQuery(Unknown Source)
[...]

If I include the table="" part, I get the NullPointerException at:

so it seems that the existing class definition is not merged with the additional data but overwritten.

Ommiting the extent-class-definitions from the additional xml file, I can access all classes of the base application, but not of the plugin. As we have several plugins, we dont want any dependencies from the base application to the plugins.

Any hints are appreciated.

Best regards

Bernd