+ @Override
+ public <T extends DataObject, L extends DataTreeChangeListener<T>> ListenerRegistration<L> registerDataTreeChangeListener(
+ final DataTreeIdentifier<T> treeId, final L listener) {
+ if(treeChangeService == null) {
+ throw new UnsupportedOperationException("Underlying data broker does not expose DOMDataTreeChangeService.");
+ }
+ return treeChangeService.registerDataTreeChangeListener(treeId, listener);