code: public static int getLine(Element elem) {
  		Attr attr = elem.getAttributeNodeNS(URI, LINE_ATTR);
  		return attr != null ? Integer.parseInt(attr.getValue()) : -1;
  	}
docs: Returns the line number of an element (DOM flavor)
  
  @param elem
  the element that holds the location information
  @return the element's line number or <code>-1</code> if <code>elem</code>
  has no location information.