docs: public synchronized INodeSet getNodes(ResourceFormatParser parser) throws
              ResourceModelSourceException
      {
          final Long modtime = isSupportsLastModified() ? getLastModified() : -1;
          if (0 == nodeSet.getNodes().size() || modtime < 0 || (modtime > lastModTime)) {
              nodeSet = loadNodes(parser, shouldGenerateServerNode());
              lastModTime = modtime;
          }
          return nodeSet;
      }