add(HeaderContributor.forCss("resources/yui/calendar/assets/calendar.css"));
dateField = new TextField("field", model, Date.class) {
@Override
public IConverter getConverter(Class clazz) {
return new AbstractConverter() {
private DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
public Object convertToObject(String s, Locale locale) {
if(s == null || s.trim().length() == 0) {
return null;
}