docs: public void save(XMLWriter w) throws KNXMLException
  	{
  		w.writeElement(TAG_DATAPOINTS, Collections.EMPTY_LIST, null);
  		synchronized (points) {
  			for (final Iterator i = points.values().iterator(); i.hasNext();)
  				((Datapoint) i.next()).save(w);
  		}
  		w.endElement();
  	}