code: public String getMessageCode(BaseMessage externalMessage)
      {
          if (!(externalMessage.getExternalMessage() instanceof ServiceTrxMessageIn))
              return null;
          Object message = externalMessage.getExternalMessage().getRawData();
          if (message != null)
              return "OTA_" + message.getClass().getSimpleName();
          return null;    // No type found.
      }
docs: From this external message, figure out the message type.
  @externalMessage The external message just received.
  @return The message type for this kind of message (transport specific).