public static void save(final String filename) throws IOException {
   final FileOutputStream fos = FileHelper.createFileOutputStream(filename);
   final OutputBitStream ostream = new OutputBitStream(fos);
   ostream.writeInt(ElementPropertiesLibrary.m_elements.size());
   final TIntObjectIterator<ElementProperties> iter =
       ElementPropertiesLibrary.m_elements.iterator();
   for (int i = ElementPropertiesLibrary.m_elements.size(); i > 0; --i) {
     iter.advance();
     iter.value().save(ostream);
   }
   ostream.close();
 }