== null) ? false : sortedInfo.isAscending();

      // Add column headers.
      tr = startRow();
      buildHeader(tr, firstNameHeader, firstNameColumn, sortedColumn, isSortAscending, false, false);
      buildHeader(tr, lastNameHeader, lastNameColumn, sortedColumn, isSortAscending, false, false);
      buildHeader(tr, ageHeader, ageColumn, sortedColumn, isSortAscending, false, false);
      buildHeader(tr, categoryHeader, categoryColumn, sortedColumn, isSortAscending, false, false);
      buildHeader(tr, 