How to configure a STOMP Transformer for OpenMQ/Glassfish

Question

I have wrote a basic Message Transformer to Transform object messages to Text messages. I am not Java/OpenMQ/Glassfish Expert

The Transformer compiles fine BUT now I need to configure the STOMP Bridge to use it... I cant find any examples online on how to do it.

I copied my StompTransformer.class to C:\glassfish3\glassfish\domains\domain1\lib\ext and All the required jars to: C:\glassfish3\glassfish\domains\domain1\lib\applibs (not sure if this is the right place)

I added the following into config.properties:

imq.bridge.admin.user=admin
imq.bridge.stomp.messageTransformer=StompTransformer
imq.bridge.admin.password=admin
imq.bridge.activelist=stomp
imq.bridge.enabled=true

I tried to read the documentation: https://docs.oracle.com/cd/E19587-01/821-0027/gjdnl/index.html >>> Configuring a JMS Bridge

but it is confusing to me :( I don't know what should be in the XML file, what it should be called, where I should put it and what else is needed for configuration.....

Here is the code for the Transformer:

import java.util.*;
import javax.jms.*;
import com.sun.messaging.bridge.service.MessageTransformer;
import com.thoughtworks.xstream.XStream;

 public class StompTransformer extends MessageTransformer <Message, Message> {

 public Message transform(Message message, 
                          boolean readOnly,
                          String charsetName,
                          String source, 
                          String target,
                          Properties properties)
                          throws Exception {

    Message m = message;
    if (source.equals(SUN_MQ)) { //from Java Message Queue to STOMP client

        if (message instanceof ObjectMessage) {

            //create a new TextMessage for message to be transformed to
            TextMessage tm = (TextMessage)createJMSMessage(JMSMessageType.TEXTMESSAGE);

            //convert message to the TextMessage
            XStream xstream = new XStream();
            tm.setText(xstream.toXML(message));
            m = tm;
        }
    }
    return m;
 }
}

Answer 1

With OpenMQ 4.5.2 (running stand-alone, not embedded in GlassFish) I tested the message transformation with this project

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.habarisoft</groupId>
    <artifactId>OpenMQMessageTransformer</artifactId>
    <version>1.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <dependencies>       
        <dependency>
            <groupId>org.glassfish.mq</groupId>
            <artifactId>imq</artifactId>
            <version>4.5.2</version>
        </dependency>                                            
        <dependency>
            <groupId>org.glassfish.mq</groupId>
            <artifactId>jms</artifactId>
            <version>4.5.2</version>
        </dependency>        
        <dependency>
            <groupId>org.glassfish.mq</groupId>
            <artifactId>imqjmsbridge</artifactId>
            <version>4.5.2</version>
            <type>jar</type>
        </dependency>
    </dependencies>
</project>

And this transformer class:

package com.habarisoft.mqtr;

import java.util.*;
import javax.jms.*;

import com.sun.messaging.bridge.service.MessageTransformer;

public class StompTransformer extends MessageTransformer<Message, Message> {

    @Override
    public Message transform(Message message,
            boolean readOnly,
            String charsetName,
            String source,
            String target,
            Properties properties)
            throws Exception {

        System.out.println("transform ...");

        Message m = message;
        if (source.equals(SUN_MQ)) { //from Java Message Queue to STOMP client

            if (message instanceof ObjectMessage) {

                //create a new TextMessage for message to be transformed to
                TextMessage tm = (TextMessage) createJMSMessage(JMSMessageType.TEXTMESSAGE);

                tm.setText("<converted object>");
                m = tm;
            }
        }
        return m;
    }
}

The generated JAR must be in the lib/ext directory together with other required dependency Jars (note that this has been tested with a stand-alone Open MQ installation).

and this broker configuration for the STOMP bridge:

imq.bridge.admin.user=admin
imq.instanceconfig.version=300
imq.bridge.stomp.messageTransformer=com.habarisoft.mqtr.StompTransformer
imq.bridge.admin.password=admin
imq.bridge.activelist=stomp
imq.bridge.enabled=true

Then I started a STOMP client listening for incoming messages in queue TOOL.DEFAULT, and used a JMS client to generate object messages:

import java.util.Date;
import javax.jms.Queue;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.ObjectMessage;
import javax.jms.Session;

public class Main {

    public static void main(String[] args) throws JMSException {

        ConnectionFactory cf = new com.sun.messaging.ConnectionFactory();

        Connection conn = cf.createConnection("admin", "admin");
        conn.start();

        Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
        Queue queue = session.createQueue("TOOL.DEFAULT");
        MessageProducer producer = session.createProducer(queue);

        Date date = new Date();

        ObjectMessage msg = session.createObjectMessage(date);
        producer.send(msg);
        conn.close();

    }
}

If the JMS client code sends an object message while the STOMP client is listening, the console window where the broker runs successfully writes the

transform ...

message. But then it logs an error, complaining about a null JMS destination:

Dez 10, 2014 8:04:39 AM
WARNUNG: [BSS2009]: Nachricht ID:8-192.168.56.1(ea:8a:dc:e5:15:7c)-58027-1418195
079856 kann nicht an Abonnent {98F4744E-6E12-44CC-8336-36A9BA7CDC77} ausgeliefer
t werden: JMS destination null !
javax.jms.JMSException: JMS destination null !
        at com.sun.messaging.bridge.service.stomp.StompProtocolHandler.toStompDe
stination(StompProtocolHandler.java:832)
        at com.sun.messaging.bridge.service.stomp.StompProtocolHandler.toStompFr
ameMessage(StompProtocolHandler.java:893)
        at com.sun.messaging.bridge.service.stomp.StompConnection.toStompFrameMe
ssage(StompConnection.java:438)
        at com.sun.messaging.bridge.service.stomp.StompSubscriberSession.onMessa
ge(StompSubscriberSession.java:127)
        at com.sun.messaging.jmq.jmsclient.MessageConsumerImpl.deliverAndAcknowl
edge(MessageConsumerImpl.java:358)
        at com.sun.messaging.jmq.jmsclient.MessageConsumerImpl.onMessage(Message
ConsumerImpl.java:287)
        at com.sun.messaging.jmq.jmsclient.SessionReader.deliver(SessionReader.j
ava:119)
        at com.sun.messaging.jmq.jmsclient.ConsumerReader.run(ConsumerReader.jav
a:192)
        at java.lang.Thread.run(Thread.java:745)

Dez 10, 2014 8:04:39 AM

I have not investigated this further, but it looks like more code is required to construct the transformed message than is shown in the OpenMQ JavaDoc for the transformer.

But test results show that the transformer is called and the provided example can be used as a starting point.

---

Update:

If the system architecture is under your control, then it might be easier to insert a Java (JMS) client application in the message flow, which transforms the object message to a text message and re-sends it to a distinct destination, which the STOMP client consumes.