[OJB-developers] OQL bug

[Georg S. <ge...@me...>]

Hi,

when something similar as the following OQL-Query

select allX from X where sequence.somefield = $1 ....

where the sequence field is actually an interface I get a
NullPointerException:

java.lang.NullPointerException
        at
ojb.broker.metadata.ClassDescriptor.getPkFields(ClassDescriptor.java:869)
        at
ojb.broker.accesslayer.SqlGenerator$JoinInfo.asSqlClause(SqlGenerator.java:66)
        at
ojb.broker.accesslayer.SqlGenerator.getJoinClause(SqlGenerator.java:914)
        at
ojb.broker.accesslayer.SqlGenerator.getPreparedSelectStatement(SqlGenerator.java:685)
        at
ojb.broker.accesslayer.JdbcAccess.executeQuery(JdbcAccess.java:186)
        at ojb.broker.accesslayer.RsIterator.<init>(RsIterator.java:179)
        at
ojb.broker.singlevm.PersistenceBrokerImpl.getIteratorFromQuery(PersistenceBrokerImpl.java:1181)
        at
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBrokerImpl.java:901)
        at
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBrokerImpl.java:986)
        at
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBrokerImpl.java:958)
        at ojb.odmg.oql.OQLQueryImpl.execute(OQLQueryImpl.java:229)


I looked a little bit around and the problem seems to be in the inner
class JoinInfo in SqlGenerator which tries to do the following

            refCld =
aCld.getRepository().getDescriptorFor(anOrd.getItemClass());


anOrd.getItemClass() of course is an interface which as a Descriptor
doesn't have any fields. I suppose the interface would have to be
substituted somehow by the actual classes implementing that interface and
maybe this would mean having to do various actual SQL-Queries each with a
concrete class and then somehow merging the result, or doing an
(outer) join over all the concrete class tables involved and then somehow
postprocessing the result again.

regards

Georg