public void actionPerformed(ActionEvent e) {
   if (UpdateMediator.instance().isUpdateDownloaded()) {
     UpdateMediator.instance().startUpdate();
   } else {
     UpdateMediator.instance().checkForUpdate();
   }
 }
    public void refresh() {
      String text;
      boolean enabled = true;

      if (UpdateMediator.instance().isUpdated()) {
        text =
            I18n.tr("You are up to date with FrostWire")
                + " v."
                + UpdateMediator.instance().getLatestVersion();
      } else if (UpdateMediator.instance().isUpdateDownloading()) {
        text = I18n.tr("Downloading update...");
        enabled = false;
      } else if (UpdateMediator.instance().isUpdateDownloaded()) {
        text = I18n.tr("Install update") + " v." + UpdateMediator.instance().getLatestVersion();
      } else {
        text = I18n.tr("Check for update");
      }

      putValue(NAME, text);
      putValue(LONG_DESCRIPTION, text);
      setEnabled(enabled);
    }