<!--
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.
-->
<html>
<head>
<title>ActiveMQ Artemis Asynchronous Send Acknowledgements Example</title>
<link rel="stylesheet" type="text/css" href="../../../common/common.css" />
<link rel="stylesheet" type="text/css" href="../../../common/prettify.css" />
<script type="text/javascript" src="../../../common/prettify.js"></script>
</head>
<body onload="prettyPrint()">
<h1>Asynchronous Send Acknowledgements Example</h1>
<pre>To run the example, simply type <b>mvn verify</b> from this directory, <br>or <b>mvn -PnoServer verify</b> if you want to start and create the server manually.</pre>
<p>Asynchronous Send Acknowledgements are an advanced feature of ActiveMQ Artemis which allow you to
receive acknowledgements that messages were successfully received at the server in a separate thread to the sending thread<p/>
<p>In this example we create a normal JMS session, then set a SendAcknowledgementHandler on the JMS
session's underlying core session. We send many messages to the server without blocking and asynchronously
receive send acknowledgements via the SendAcknowledgementHandler.
<p>For more information on Asynchronous Send Acknowledgements please see the user manual</p>
<h2>Example step-by-step</h2>
<p><i>To run the example, simply type <code>mvn verify -Pexample</code> from this directory</i></p>
<ol>
<li>First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get it's properties from the <code>client-jndi.properties</code> file in the directory <code>../common/config</code></li>
<pre class="prettyprint">
<code>InitialContext initialContext = getContext();</code>
</pre>
<li>We look-up the JMS queue object from JNDI</li>
<pre class="prettyprint">
<code>Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");</code>
</pre>
<li>We look-up the JMS connection factory object from JNDI</li>
<pre class="prettyprint">
<code>ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");</code>
</pre>
<li>We create a JMS connection</li>
<pre class="prettyprint">
<code>connection = cf.createConnection();</code>
</pre>
<li>Define a SendAcknowledgementHandler which will receive asynchronous acknowledgements</li>
<pre class="prettyprint">
<code>
class MySendAcknowledgementsHandler implements SendAcknowledgementHandler
{
int count = 0;
public void sendAcknowledged(final Message message)
{
System.out.println("Received send acknowledgement for message " + count++);
}
}
</code>
</pre>
<li>Create a JMS session</li>
<pre class="prettyprint">
<code>Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>Set the handler on the underlying core session</li>
<pre class="prettyprint">
<code>
ClientSession coreSession = ((ActiveMQSession)session).getCoreSession();
coreSession.setSendAcknowledgementHandler(new MySendAcknowledgementsHandler());
</code>
</pre>
<li>Create a JMS Message Producer</li>
<pre class="prettyprint">
<code>
MessageProducer producer = session.createProducer(queue);
producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
</code>
</pre>
<li>Send 5000 messages, the handler will get called asynchronously some time later after the messages are sent.</li>
<pre class="prettyprint">
<code>
final int numMessages = 5000;
for (int i = 0; i < numMessages; i++)
{
javax.jms.Message jmsMessage = session.createMessage();
producer.send(jmsMessage);
System.out.println("Sent message " + i);
}
</code>
</pre>
<li>And finally, <b>always</b> remember to close your JMS connections and resources after use, in a <code>finally</code> block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects</li>
<pre class="prettyprint">
<code>finally
{
if (initialContext != null)
{
initialContext.close();
}
if (connection != null)
{
connection.close();
}
}</code>
</pre>
</ol>
</body>
</html>
f2db1c4337