code: 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;
      }
docs: Add a new succeeding cell to this cell, based on a new valid address value
  that
  can follow this cell's value, into the address tree. This is done
  by adding the new cell to the hashtable of next cells.
  
  @param newValue
  a valid value, that can follow this cell's value, in the address
  tree
  @return the new cell that was added.