*/
public FieldOnlyFilter (ReferenceTypeId refId, /*Field*/ReferenceTypeId fid)
throws InvalidClassException, InvalidFieldException
{
if (refId == null || refId.getReference().get () == null)
throw new InvalidClassException (refId.getId ());
if (fid == null)
throw new InvalidFieldException (fid.getId ());
_refId = refId;