// extensions
Set exts = tag.getExtensions();
if (exts != null) {
Iterator itr = exts.iterator();
while (itr.hasNext()) {
Extension e = (Extension)itr.next();
setExtension(e.getSingleton(), e.getValue());
//TODO: setExtension may throw an IllformedLocaleException.
// In this csae, error index must be recalculated.
}
}
// private use