RC9/qpid/java/client/example/src/main/java/org/apache/qpid/example/publisher/Publisher.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.qpid.example.publisher;

import org.apache.qpid.client.AMQConnectionFactory;

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.DeliveryMode;
import javax.jms.Queue;
import javax.jms.MessageProducer;
import javax.jms.Connection;
import javax.jms.Session;

import javax.naming.InitialContext;

import org.apache.qpid.example.shared.InitialContextHelper;
import org.slf4j.LoggerFactory;
import org.slf4j.Logger;

public class Publisher
{
    private static final Logger _log = LoggerFactory.getLogger(Publisher.class);

    protected InitialContextHelper _contextHelper;

    protected Connection _connection;

    protected Session _session;

    protected MessageProducer _producer;

    protected String _destinationDir;

    protected String _name = "Publisher";

    protected Queue _destination;

    protected static final String _defaultDestinationDir = "/tmp";

    /**
     * Creates a Publisher instance using properties from example.properties
     * See InitialContextHelper for details of how context etc created
     */
    public Publisher()
    {
        try
        {
            //get an initial context from default properties
            _contextHelper = new InitialContextHelper(null);
            InitialContext ctx = _contextHelper.getInitialContext();

            //then create a connection using the AMQConnectionFactory
            AMQConnectionFactory cf = (AMQConnectionFactory) ctx.lookup("local");
            _connection = cf.createConnection();

            //create a transactional session
            _session = _connection.createSession(true, Session.AUTO_ACKNOWLEDGE);

            //lookup the example queue and use it
            //Queue is non-exclusive and not deleted when last consumer detaches
            _destination = (Queue) ctx.lookup("MyQueue");

            //create a message producer
            _producer = _session.createProducer(_destination);

            //set destination dir for files that have been processed
            _destinationDir = _defaultDestinationDir;

            _connection.start();
        }
        catch (Exception e)
        {
            e.printStackTrace();
            _log.error("Exception", e);
        }
    }

    /**
     * Publishes a non-persistent message using transacted session
     * Note that persistent is the default mode for send - so need to specify for transient
     */
    public boolean sendMessage(Message message)
    {
        try
        {
            //Send message via our producer which is not persistent
            _producer.send(message, DeliveryMode.NON_PERSISTENT, _producer.getPriority(), _producer.getTimeToLive());

            //commit the message send and close the transaction
            _session.commit();

        }
        catch (JMSException e)
        {
            //Have to assume our commit failed and rollback here
            try
            {
                _session.rollback();
                _log.error("JMSException", e);
                e.printStackTrace();
                return false;
            }
            catch (JMSException j)
            {
                _log.error("Unable to rollback publish transaction ",e);
                return false;
            }
        }

        _log.info(_name + " finished sending message: " + message);
        return true;
    }

    /**
     * Cleanup resources before exit
     */
    public void cleanup()
    {
        try
        {
            if (_connection != null)
            {
                _connection.stop();
                _connection.close();
            }
            _connection = null;
            _producer = null;
        }
        catch(Exception e)
        {
            _log.error("Error trying to cleanup publisher " + e);
            System.exit(1);
        }
    }

    /**
     * Exposes session
     * @return  Session
     */
    public Session getSession()
    {
        return _session;
    }

    public String getDestinationDir()
    {
        return _destinationDir;
    }

    public void setDestinationDir(String destinationDir)
    {
        _destinationDir = destinationDir;
    }

    public String getName()
    {
        return _name;
    }

    public void setName(String _name) {
        this._name = _name;
    }
}