code: public boolean parseUnrecognizedElement(Element element, Properties props) throws Exception {
          if ("dataSource".equals(element.getNodeName())) {
              Object instance =
                      DOMConfigurator.parseElement(element, props, DataSource.class);
              if (instance instanceof DataSource) {
                 setDataSource((DataSource) instance);
              }
              return true;
          }
          return false;
    }
docs: {@inheritDoc}