Test whether notification enabled for this event.
Return true if:
- Either the set of accepted names is empty (implying that all
attribute names are of interest) or the set of accepted names
includes the name of the attribute in this notification
if (notification == null)
return (false);
synchronized (names) {
if (names.size() < 1)
return (true);
else
return (names.contains(notification.getType()));
}