code: protected String sendRequestToDF(String df_service, Object msgContent) {
  
          IDFComponentDescription[] receivers = getReceivers(df_service);
          if (receivers.length > 0) {
              IMessageEvent mevent = createMessageEvent("send_request");
              mevent.getParameter(SFipa.CONTENT).setValue(msgContent);
              for (int i = 0; i < receivers.length; i++) {
                  mevent.getParameterSet(SFipa.RECEIVERS).addValue(
                          receivers[i].getName());
                  logger.info("The receiver is " + receivers[i].getName());
              }
              sendMessage(mevent);
          }
          logger.info("Message sended to " + df_service + " to "
                  + receivers.length + " receivers");
          return ("Message sended to " + df_service);
      }
docs: Method to send Request messages to a specific df_service
  
  @param df_service
  The name of the df_service
  @param msgContent
  The content of the message to be sent
  @return Message sent to + the name of the df_service