@Override
    public boolean isSortable(final int column) {
      final TableModel model = getModel();
      if (model instanceof SortableColumnModel) {
        final ColumnInfo[] columnInfos = ((SortableColumnModel)model).getColumnInfos();
        if (column >= 0 && column < columnInfos.length) {
          return columnInfos[column].isSortable() && columnInfos[column].getComparator() != null;
        }
      }

      return false;
    }
@Override
    public boolean isSortable(final int column)