code: public FilterCellSlowStr addNewCell(String newValue) {
          if (!newValue.equals(FilterListSlowStr.wildCard)) {
              if (nextCell == null) {
                  nextCell = new HashMap<String, FilterCellSlowStr>();
              }
  
              FilterCellSlowStr newCell = new FilterCellSlowStr();
              nextCell.put(newValue, newCell);
              return newCell;
          }
          if (wildcardCell == null) {
              wildcardCell = new FilterCellSlowStr();
          }
          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.