void save(List/*<GanttPreviousState*/ history, TransformerHandler handler) throws SAXException, ParserConfigurationException, IOException {
AttributesImpl attrs = new AttributesImpl();
startElement("previous", handler);
for (int i=0; i<history.size(); i++) {
final GanttPreviousState nextState = (GanttPreviousState) history.get(i);
final List/*<GanttPreviousStateTask>*/ stateTasks = nextState.load();
addAttribute("name", nextState.getName(), attrs);
startElement("previous-tasks", attrs, handler);
// ArrayList list =
// ((GanttPreviousState)previous.get(i)).getTasks();
for (int j=0; j<stateTasks.size(); j++) {