public ValueType getDomainType() {
   if (categorical) {
     return ValueType.NOMINAL;
   } else {
     return dataTableColumn.getValueType();
   }
 }
 private void update() {
   index = DataTableColumn.getColumnIndex(dataTable, dataTableColumn);
   upToDate = true;
 }
 /**
  * Finds the column index for the column named like dataTableColumn.getName in dataTable, checks
  * if that column in the data table is compatible with to settings of dataTableColumn (value type
  * etc.), and updates this.columnIdx.
  *
  * <p>If the column does not exist or is not compatible, the columnIdx is set to -1.
  */
 public static int getColumnIndex(DataTable dataTable, DataTableColumn dataTableColumn) {
   return getColumnIndex(dataTable, dataTableColumn.getName(), dataTableColumn.getValueType());
 }