private void addEventHandler(Class<? extends Event> event,
			IEventHandler handler, int priority) {
		TreeMap<Integer, IEventHandler> map = new TreeMap<Integer, IEventHandler>();
		map.put(priority, handler);
		TreeMap<Integer, IEventHandler> tmp = eventHandlers.get(event);
		if (tmp == null) {
			tmp = new TreeMap<Integer, IEventHandler>();
		}
		tmp.putAll(map);
		eventHandlers.put(event, tmp);
	}