code: public boolean isInClosedList(long ref) {
          if (m_nodePool == null) {
              return false;
          }
          for (Node n : m_nodePool.findNodes(ref)) {
              if ((n.flags & DT_NODE_CLOSED) != 0) {
                  return true;
              }
          }
          return false;
      }
docs: The closed list is the list of polygons that were fully evaluated during the last navigation graph search. (A* or
  Dijkstra)