@Override
  public String getElementUrl(Object element) {
    final TreeSet<WorkingSetSerializable> serializables = ourSerializables.get(element.getClass().getName());
    if (serializables != null && !serializables.isEmpty()) {
      final WorkingSetSerializable last = serializables.last();
      try {
        final StringBuilder sb = new StringBuilder();
        sb.append(last.getId());
        sb.append(' ');
        sb.append(last.getVersion());
        sb.append(' ');

        last.serializeMe(element, sb);
        return sb.toString();
      }
      catch (IOException e) {
        LOG.info(e);
        return null;
      }
    }
    return null;
  }
@Override
  public String getElementUrl(Object element)