code: public int compare(Object objA, Object objB)
      {
          String idAStr = _table.getColumn((String)objA).getProperty("id");
          String idBStr = _table.getColumn((String)objB).getProperty("id");
          int idA;
          int idB;
  
          try {
              idA = Integer.parseInt(idAStr);
          }
          catch (Exception ex) {
              return 1;
          }
          try {
              idB = Integer.parseInt(idBStr);
          }
          catch (Exception ex) {
              return -1;
          }
          return idA < idB ? -1 : (idA > idB ? 1 : 0);
      }
docs: Compares two columns given by their names.
  
  @param objA  The name of the first column
  @param objB  The name of the second column
  @return
  @see         java.util.Comparator#compare(java.lang.Object, java.lang.Object)