* descriptor). If it doesn't exists, then an exception is thrown. If it exists (i.e.
* it is simply an optional group not yet defined), then returns an empty list.
*/
if (groups.isEmpty()) {
final ParameterDescriptorGroup descriptor = values.descriptor;
if (!(descriptor.descriptor(name) instanceof ParameterDescriptorGroup)) {
throw new ParameterNotFoundException(Errors.format(
Errors.Keys.ParameterNotFound_2, descriptor.getName(), name), name);
}
}
return groups;