code: public void reload() {
          try {
              if (_toplevel.specifics != null) _toplevel.specifics.clear();
              _toplevel.global = null;
  
              for (T object: _toplevel.retriever.call()) {
                  _toplevel.insert(object, _toplevel.coordinates, 0);
              }
              if (_toplevel.global == null) throw new IllegalStateException("***GlobalDataObjectMissing");
  
              _toplevel.spread();
          } catch (Exception x) {
              throw new RuntimeException(x.getMessage(), x);
          }
      }
docs: (Re)loads data objects from an external source.