private static StringBuffer generateColumnHeadersFromHtmlFormHelper(HtmlFormField hff, List<String> extraCols, StringBuffer sb){
if (hff instanceof ObsField){
ObsField of = (ObsField) hff;
sb = buildHeadersForObsField(of, extraCols, sb);
} else if (hff instanceof ObsGroup){
ObsGroup og = (ObsGroup) hff;
for (HtmlFormField of : og.getChildren()){
sb = generateColumnHeadersFromHtmlFormHelper(of, extraCols, sb);
}
}
return sb;
}