/** Create a new document that contains data from the given file. */
 @Override
 public Document createDocument(Application app, File file) {
   TextDocument d = new TextDocument(app);
   d.setFile(file);
   return d;
 }
 /** Create a new document that contains data from the given URL. */
 @Override
 public Document createDocument(Application app, URL url) {
   TextDocument d = new TextDocument(app);
   d.setURL(url);
   return d;
 }