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Introduction

This document describes how messages can be sent to and received from a messaging queue and how those messages can be processed in a Java class to add an order to a JobScheduler job chain.

No JobScheduler libraries are needed for this example.

Mode Of Operation

  • Creating a message producer to send messages to a Message Queue (MQ) server.
  • Creating a message consumer to receive messages from a MQ server.
  • Sending the message to a Jobscheduler.

To be able to process the message on the desired JobScheduler the message has to be a XML snippet wich can be processed by the JobScheduler API respectively by the JobScheduler XML interface.

The Message Producer

SOSProducer.java 
package com.sos.jms.producer;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageProducer;
import javax.jms.Session;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.log4j.Logger;

public class SOSProducer {
    private static final String DEFAULT_CONNECTION_URI = "tcp://[HOSTNAME]:61616";
    private static final Logger LOGGER = Logger.getLogger(SOSProducer.class);
    private static final String QUEUE_NAME = "test_queue";
    private static final String TEXT = "<add_order job_chain='[FOLDERNAME]/[JOBCHAINNAME]' at='now'>"
            + "<params>"
            + "<param name='host' value='[HOST]'/>"
            + "<param name='port' value='22'/>"
            + "<param name='user' value='[USERNAME]'/>"
            + "<param name='auth_method' value='password'/>"
            + "<param name='password' value='[PASSWORD]'/>"
            + "<param name='command' value='echo command send over MessageQueue!'/>"
            + "</params>"
            + "</add_order>";
    
    private Connection createConnection(){
        return this.createConnection(DEFAULT_CONNECTION_URI);
    }
    
    private Connection createConnection(String uri){
        ConnectionFactory factory = new ActiveMQConnectionFactory(uri);
        Connection connection = null;
        try {
            connection = factory.createConnection();
        } catch (JMSException e) {
            LOGGER.error("JMSException occurred while trying to connect: " , e);
        }
        return connection;
    }
    
    private Session createSession(Connection connection){
        Session session = null;
        try {
            session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        } catch (JMSException e) {
            LOGGER.error("JMSException occurred while trying to create Session: " , e);
        }
        return session;
    }
    
    private Destination createDestination(Session session){
        Destination destination = null;
        try {
            destination = session.createQueue(QUEUE_NAME);
        } catch (JMSException e) {
            LOGGER.error("JMSException occurred while trying to create Destination: " , e);
        }
        return destination;
    }
    
    private MessageProducer createMessageProducer(Session session, Destination destination){
        MessageProducer producer = null;
        try {
            producer = session.createProducer(destination);
        } catch (JMSException e) {
            LOGGER.error("JMSException occurred while trying to create MessageProducer: " , e);
        }        
        return producer;
    }
    
    public void write(String text){
        Connection connection = createConnection();
        Session session = createSession(connection);
        Destination destination = createDestination(session);
        MessageProducer producer = createMessageProducer(session, destination);
        Message message = null;
        try {
            if(text != null){
                message = session.createTextMessage(text);
            } else{
                message = session.createTextMessage(TEXT);
            }
            producer.send(message);
        } catch (JMSException e) {
            LOGGER.error("JMSException occurred while trying to write Message to Destination: " , e);
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (JMSException e) {
                    LOGGER.error("JMSException occurred while trying to close the connection: " , e);
                }
            }
        }
    }
    
}

 

 

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