public void execute() {
try {
if (getValue("xmlfile") == null) throw new InstantiationException("You need to choose an xml file");
if (getValue("pdffile") == null) throw new InstantiationException("You need to choose a source PDF file");
PdfReader reader = new PdfReader(((File)getValue("pdffile")).getAbsolutePath());
reader.consolidateNamedDestinations();
List<HashMap<String, Object>> bookmarks = SimpleBookmark.getBookmark( reader );
// save them in XML format
FileOutputStream bmWriter = new FileOutputStream( (File)getValue("xmlfile") );
SimpleBookmark.exportToXML(bookmarks, bmWriter, "UTF-8", false);
bmWriter.close();