code: public synchronized void register(XEvent event) {
  		String classId = classifier.getClassIdentity(event);
  		XEventClass eventClass = classMap.get(classId);
  		if (eventClass == null && classId != null) {
  			eventClass = new XEventClass(classId, classMap.size());
  			classMap.put(classId, eventClass);
  		}
  		if (eventClass != null) {
  			eventClass.incrementSize();
  		}
  	}
docs: Registers an event with this set of event classes. This will potentially
  add a new event class to this set of event classes. An event class will
  be incremented in size, if the given event is found to be a member of it.
  
  @param event
  The event to be analyzed.