com.techempower.gemini.cluster.jms.AsyncSubscriber Maven / Gradle / Ivy
Show all versions of gemini Show documentation
/*******************************************************************************
* Copyright (c) 2018, TechEmpower, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name TechEmpower, Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL TECHEMPOWER, INC. BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*******************************************************************************/
package com.techempower.gemini.cluster.jms;
import com.techempower.gemini.GeminiApplication;
import com.techempower.log.ComponentLog;
import javax.jms.*;
/**
* AsyncSubscriber is a thin wrapper for a JMS consumer with an attached
* MessageListener (publisher-subscriber message pattern)
*/
public class AsyncSubscriber
implements AutoCloseable
{
private final Connection connection;
private final ComponentLog log;
private Session session;
private MessageConsumer consumer;
private final String destination;
/**
* Constructor. This is of a type AutoCloseable, so this should be
* used in a try-with construct.
*
* Note: Do not recreate Connection objects unless you are targeting
* a different connection/socket, since different sessions can be built from
* the same connection object. Connection objects are resource heavy
*/
public AsyncSubscriber(GeminiApplication application,
Connection connection, String destination)
{
this.connection = connection;
this.log = application.getLog("AsyS");
this.destination = destination;
}
/**
* Starts a AsyncSubscriber and connects to the topic "destination",
* attaching a listener to the session
*/
public AsyncSubscriber start(MessageListener listener) throws JMSException
{
connection.start();
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
consumer = session.createConsumer(session.createTopic(destination));
consumer.setMessageListener(listener);
log.log(connection + " AsyncSubscriber@'" + destination + "'");
return this;
}
/**
* Closes this session and consumer
*/
@Override
public void close()
{
log.log("AsyncSubscriber <" + consumer + "> is closing session <"
+ session + "> @topic://" + destination);
try
{
if (consumer != null)
{
consumer.close();
}
if (session != null)
{
session.close();
}
}
catch (JMSException e)
{
log.log("AsyncSubscriber <" + consumer
+ "> exception while closing session <" + session + "> @topic://"
+ destination, e);
}
}
}