code: public org.w3c.dom.Document outputW3CDom(final WireFeed feed) throws IllegalArgumentException, FeedException {
          final Document doc = outputJDom(feed);
          final DOMOutputter outputter = new DOMOutputter();
          try {
              return outputter.output(doc);
          } catch (final JDOMException jdomEx) {
              throw new FeedException("Could not create DOM", jdomEx);
          }
      }
docs: Creates a W3C DOM document for the given WireFeed.
  <p>
  This method does not use the feed encoding property.
  <p>
  NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'.
  <p>
  
  @param feed Abstract feed to create W3C DOM document from. The type of the WireFeed must
  match the type given to the FeedOuptut constructor.
  @return the W3C DOM document for the given WireFeed.
  @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed
  don't match.
  @throws FeedException thrown if the W3C DOM document for the feed could not be created.