docs: public FilterCell addNewCell(int newValue) {
          if (newValue != -1) {
              if (nextCell == null) {
                  nextCell = new FastSynchHashTable();
              }
  
              FilterCell newCell = new FilterCell();
              nextCell.put(newValue, newCell);
  
              return newCell;
          }
          if (wildcardCell == null) {
              wildcardCell = new FilterCell();
          }
          return wildcardCell;
      }