@Override
  @POST
  @Path("/username/")
  public String devicesFromUsername(@FormParam("username") final String username) {
    List<Device> devices = findDevicesByUsername(username);
    String result = "{\"username\":\"" + username + "\",\"devices\":[";
    String sDevices = "";
    Iterator<Device> i = devices.iterator();

    while (i.hasNext()) {
      Device d = i.next();
      sDevices += "\"" + d.getDeviceId() + "\",";
    }

    if (sDevices.length() > 0) {
      sDevices = sDevices.substring(0, sDevices.length() - 1);
    }

    result += sDevices + "]}";
    return result;
  }