code: public Object unmarshal(HierarchicalStreamReader reader,
  			UnmarshallingContext context) {
  		XEventImpl event = new XEventImpl();
  
  		String id = reader.getAttribute("xid");
  		event.setID(XID.parse(id));
  
  		if (reader.hasMoreChildren()) {
  			reader.moveDown();
  			XAttributeMap attributes = (XAttributeMap) context.convertAnother(
  					event, XAttributeMap.class,  XesXStreamPersistency.attributeMapConverter);
  			event.setAttributes(attributes);
  			reader.moveUp();
  		}
  		return event;
  	}
docs: /*
  (non-Javadoc)
  
  @see
  com.thoughtworks.xstream.converters.Converter#unmarshal(com.thoughtworks
  .xstream.io.HierarchicalStreamReader,
  com.thoughtworks.xstream.converters.UnmarshallingContext)