Interacting with JADE Agents from non-JADE environments using the JMS-MTP

Date: January 14, 2004

JMS-MTP version 1.0

Java platform: Sun JDK 1.4 Linux

JADE version 2.1

Purpose

The aim of this tutorial is to illustrate how to interact with JADE agents from a J2EE-based (non-agent) Java environment using the JMS-MTPs.

Prerequisites

This tutorial assumes the following:

You have basic knowledge of the Java language and have Java (JDK1.4) properly installed.

You have basic knowledge of the JADE framework and have JADE (JADE-3.1 recommended) properly installed.

You have basic knowledge of the JMS-MTP and are familiar with the JMS-MTP Tutorial.

You have the JMS-MTP installed and configured with your Jade platform, see the JMS-MTP Tutorial for more details.

You have a JMS provider installed and configured to work with the JMS-MTP.

You have the Jakarta Ant tool properly installed.

You have the JADE PingAgent examples installed and working.

Compiling

Usage

First start your JMS Provider and setup the required queue (see next section), then start the JADE container using the JMS-MTP and running a PingAgent, 'ping', from the JADE examples. In order to run the example client, the jmsmtp-examples.jar and jmsmtp-util.jar files must be on the classpath. Here is an example of how you would start the example assuming you are in the root of the Jade directory:

Configuring the JadeQueueSender Example

The default settings for the JadeQueueSender are listed below, the default JMS provider is OpenJMS running on localhost. The constants/settings will be used in the following sections of code:

These setting can be changed in the ie.nuigalway.ecrg.jade.jmsmtp.examples.JadeQueueSender class.
(Note: for new setting to take effect you will need to recompile the example)

JMS-MTP Example Description

Utility Classes
This example uses two utility classes (located in jmsmtp-util.jar) to encode and decode messages used to interact with the PingAgent. These utility classes are:


// Assuming connection to JMS provider setup


jadeQueue = (Queue) ctx.lookup(PLATFORM_DEST);


QueueSender sender = session.createSender(jadeQueue);





//Create an ACL Message object using JADE API.


ACLMessage msg = new ACLMessage(ACLMessage.QUERY_REF);





//Sender properties


AID s_aid = new AID();


s_aid.setName("JadeQueueSenderExample");





// Use a JMS-MTP Address as the return address for the agent to reply to


// This client will listen to 'rmi://localhost:1099/JadeQueueSenderExample'


// Set the other options of the address to your desired setting,


// in this case non persistent FIPA XML messages


s_aid.addAddresses(REPLY_TO_JMSMTP_ADDRESS);


msg.setSender(s_aid);





// Alternatively we are also able to get the agent to reply to another agent. i.e.:


// Reply to self: s_aid.setName("ping@mogador:1098/JADE");


// or reply to another agent: s_aid.setName("personal_agent@mogador:1098/JADE");





// Setup the PingAgents properties (This is the agent that will receive the message)


AID pingAgent = new AID();


pingAgent.setName(PING_AGENT_NAME);


msg.addReceiver(pingAgent);





// Set the message content "ping" 


msg.setContent("ping");


msg.setDefaultEnvelope();





// Encode map message


Message message = session.createMapMessage();


mapUtil.encode((MapMessage) message, msg.getEnvelope(), msg.toString());





// Or use a FIPA XML Message


//TextMessage message = session.createTextMessage();


//message.setText(xmlUtil.encode(msg.getEnvelope(), msg.toString()));





// Send the message


sender.send(message);


// Assume listener is set to listen to REPLY_TO_DEST


public void onMessage(Message msg) {





  StringBuffer payload = new StringBuffer();


  Envelope env = new Envelope();





  if (msg instanceof TextMessage) {





    // Text Message received


    TextMessage tm = (TextMessage) msg;





    try {


      // Decode XML


      env = xmlUtil.decode(tm.getText(), payload);


    } catch (Exception jmse) {


      // Error in JMS TextMessage Extraction


    }





  } else if (msg instanceof MapMessage) {





     // Map Message received


    MapMessage mm = (MapMessage) msg;





    try {


      // Decode MapMessage


      env = mapUtil.decode(mm, payload);


    } catch (Exception jmse) {


      // Error in JMS MapMessage Extraction


    }


  }





  // Message decode


  System.out.println("Message body:" + payload.toString());


}