code: public static List<IdName> getParameterValues(Connection con, QueryParameter parameter)
              throws SQLException, DialectException {
  
          List<IdName> values = new ArrayList<IdName>();
          if (parameter == null) {
              return values;
          }        
          String source = parameter.getSource();
          if (parameter.isManualSource()) {
              if (!parameter.isDependent()) {
                  values = getSelectValues(con, source, true, parameter.getOrderBy());
              }
          } else {
              int index = source.indexOf(".");
              int index2 = source.lastIndexOf(".");
              String tableName = source.substring(0, index);
              String columnName;
              String shownColumnName = null;
              if (index == index2) {
                  columnName = source.substring(index + 1);
              } else {
                  columnName = source.substring(index + 1, index2);
                  shownColumnName = source.substring(index2 + 1);
              }
              values = getColumnValues(con, parameter.getSchema(), tableName, columnName, shownColumnName, parameter.getOrderBy());
          }
          return values;
      }
docs: Get values for a parameter from a database
  If a parameter is dependent of another parameter(s) his values will not be loaded
  
  @param con       connection to database
  @param parameter parameter
  @return a list of parameter values
  @throws SQLException     if an error to sql execution appears
  @throws DialectException if dialect not found