public void save(File dir) {
    Element root = DocumentHelper.createElement("builds");
    root.addAttribute("version", VERSION);

    Document doc = DocumentHelper.createDocument(root);

    synchronized (builds) {
      for (BuildFragment build : builds) {
        root.add(build.toXML());
      }
    }

    File file = new File(dir, OUTPUT_NAME);
    try {
      XMLHelper.writeXML(doc, file);
    } catch (MonitorException e) {
      logger.error("Write document " + file + " failed!", e);
    }
  }