Well I think this is what you are talking about:

#----------------------------------------------------------------------------------------
# OQL / SQL settings
#----------------------------------------------------------------------------------------
# The OqlCollectionClass entry defines the collection type returned
# from OQL queries. By default this value is set to DListImpl.
# This will be good for most situations as DList allows maximum flexibility
# in a ODMG environment. See also section 'ODMG settings'.
# Using DLists for large resultsets may be bad for application performance.
# For these scenarios you can use ArrayLists or Vectors.
# Important note: the collections class to be used MUST implement the
# interface org.apache.ojb.broker.ManageableCollection.
#
OqlCollectionClass=org.apache.ojb.odmg.collections.DListImpl_2
# OqlCollectionClass=org.apache.ojb.broker.util.collections.ManageableArrayList
# OqlCollectionClass=org.apache.ojb.broker.util.ManageableVector
#


What happens here is that I get DListImpl_2 when I execute the typical
OQL query:   select myniceObjects from A.getClass().getName();
but when I ask for an embedded property, I mean something like:
select x.B.c from A.getClass().getName();
I get a org.apache.ojb.broker.util.collections.ManageableArrayList.

The main problem I have is that there's not a lot of documentation about
DCollections or ManageableCollections, so i was trying to guess which
uses could be given to such classes (not just DList but the complete
DCollection family and the ManageableCollection family also). Any ideas
about that would be very interesting to me.


On Fri, 2004-07-09 at 09:04, Thomas Dudziak wrote:
> Martin I. Levi wrote:
> 
> > Hi!
> > 
> > As i didn't have an answer to my last mail 
> > im writing again.
> > 
> > Lets suppose I have a mapping like the following:
> > 
> > 
> >   B(c)     This means: A has a FK to B and C and A has properties a,b.
> >  /         B has property c.
> > A(a,b)     C has a FK to D and has property d.
> >  \         D has properties e and f.
> >   C(d)
> >    \
> >     D(e,f)
> > 
> > If I submit an OQL query like this:
> > 
> > "select x.C.D.e, x.B.c from A;"
> > 
> > Im not generating any already-defined objects so I was expecting to get
> > a DList of Object[] or something like that and I get a
> > org.apache.ojb.broker.util.collections.ManageableArrayList 
> > not a org.odmg.DList anymore, why is that?
> > what are this Manageable* containers for?
> > Are implemented any kind of queries which return DBags, DSets or DMaps?
> 
> OQL queries should return instances of the class specified via the 
> OqlCollectionClass setting in OJB.properties. If you have a different 
> class than ManageableArrayList configured there, then you've hit a bug.
> 
> Tom
> 
> 
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-- 
Saludos,

Martin I. Levi

Centre Tecnol�gic de Transferenci�ncia de Calor
Universitat Polit�cnica de Catalunya
www.cttc.upc.edu


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