code: private boolean evalFormElement(final AjaxRequestTarget _target,
                                      final StringBuilder _html,
                                      final UIForm _uiform)
          throws EFapsException
      {
          AjaxSubmitCloseButton.LOG.trace("entering evalFormElement");
          boolean ret = true;
          for (final Element element : _uiform.getElements()) {
              if (element.getType().equals(ElementType.FORM)) {
                  final FormElement formElement = (FormElement) element.getElement();
                  for (final Iterator<FormRow> uiRowIter = formElement.getRowModels(); uiRowIter.hasNext();) {
                      for (final IUIElement object : uiRowIter.next().getValues()) {
  
                      }
                  }
              } else if (element.getType().equals(ElementType.SUBFORM)) {
                  final UIFieldForm uiFieldForm = (UIFieldForm) element.getElement();
                  final boolean tmp = evalFormElement(_target, _html, uiFieldForm);
                  ret = ret ? tmp : ret;
              } else if (element.getType().equals(ElementType.TABLE)) {
                  final UIFieldTable uiFieldTable = (UIFieldTable) element.getElement();
                  final List<UITableHeader> headers = uiFieldTable.getHeaders();
                  for (final UIRow uiRow : uiFieldTable.getValues()) {
                      uiRow.getUserinterfaceId();
                      final Iterator<UITableHeader> headerIter = headers.iterator();
                      for (final IFilterable filterable : uiRow.getCells()) {
                          headerIter.next();
                      }
                  }
              }
          }
          return ret;
      }
docs: Recursive method to validate the elements of the form.
  @param _target   AjaxRequestTarget
  @param _html     StringBuilder for the warning message
  @param _uiform   UIForm to start the validation
  @return true if validation was valid, else false
  @throws EFapsException on error