@Override
 public int removeRecords(IDataFilter filter) {
   return getRecordStore(filter.getRecordType()).remove(filter);
 }
 @Override
 public Iterator<? extends IDataRecord> getRecordIterator(IDataFilter filter) {
   return getRecordStore(filter.getRecordType()).getRecordIterator(filter);
 }
 @Override
 public int getNumMatchingRecords(IDataFilter filter) {
   return getRecordStore(filter.getRecordType()).getNumMatchingRecords(filter);
 }
 @Override
 public Iterator<DataBlock> getDataBlockIterator(IDataFilter filter) {
   return getRecordStore(filter.getRecordType()).getDataBlockIterator(filter);
 }