private static int[][] readGroups(final Element element, final String elementName) {
    final List<Element> groupElements = element.getChildren(elementName, element.getNamespace());
    if (groupElements.isEmpty()) return null;
    int[][] groups = new int[groupElements.size()][];
    for(int i=0; i<groupElements.size(); i++) {
      Element groupElement = groupElements.get(i);
      List<Element> groupMembers = groupElement.getChildren(UIFormXmlConstants.ELEMENT_MEMBER, element.getNamespace());
      groups [i] = new int[groupMembers.size()];
      for(int j=0; j<groupMembers.size(); j++) {
        groups [i][j] = LwXmlReader.getRequiredInt(groupMembers.get(j), UIFormXmlConstants.ATTRIBUTE_INDEX);
      }
    }
    return groups;
  }
private static int[][] readGroups(final Element element, final String elementName)