resultSets.add(
new UpcastIterator<EntityContainer, BoundContainer>(
new BoundContainerIterator(new ReleasableAdaptorForIterator<Bound>(bounds.iterator()))));
resultSets.add(
new UpcastIterator<EntityContainer, NodeContainer>(
new NodeContainerIterator(new NodeReader(dbCtx, "box_node_list"))));
resultSets.add(
new UpcastIterator<EntityContainer, WayContainer>(
new WayContainerIterator(new WayReader(dbCtx, "box_way_list"))));
resultSets.add(
new UpcastIterator<EntityContainer, RelationContainer>(