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<title>ActiveMQ Client Side Failover Listener Example</title>
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<h1>Client Side Kickoff Example</h1>
<p>This example demonstrates how you can listen on failover event on the client side.</p>
<p>In this example there are two nodes running in a cluster, both server will be running for start,
but after a while the first server will crash. This will trigger an fail-over event.</p>
<h2>Example step-by-step</h2>
<p><em>To run the example, simply type <code>mvn verify</code> from this directory</em></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 its properties from <a href="src/main/resources/activemq/server0/client-jndi.properties">client-jndi.properties</a></li>
<pre class="prettyprint">
<code>InitialContext initialContext = getContext(0);</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 a JMS Connection Factory object from JNDI on server 0</li>
<pre class="prettyprint">
<code>ConnectionFactory connectionFactory = (ConnectionFactory)initialContext.lookup("/ConnectionFactory");</code>
</pre>
<li>We create a JMS connection from the same connection factory, wait a little while to make sure broadcasts from all nodes have reached the client</li>
<pre class="prettyprint">
<code>
Thread.sleep(5000);
connectionA = connectionFactory.createConnection();
((ActiveMQConnection)connectionA).setFailoverListener(new FailoverListenerImpl());
</code>
</pre>
<li>We create JMS Sessions</li>
<pre class="prettyprint">
<code>Session sessionA = connectionA.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>We create JMS MessageProducer objects on the sessions</li>
<pre class="prettyprint">
<code>MessageProducer producerA = sessionA.createProducer(queue);</code>
</pre>
<li>We send some messages on each producer</li>
<pre class="prettyprint">
<code>
final int numMessages = 10;
for (int i = 0; i < numMessages; i++)
{
TextMessage messageA = sessionA.createTextMessage("A:This is text message " + i);
producerA.send(messageA);
System.out.println("Sent message: " + messageA.getText());
}
</code>
</pre>
<li>We start the connection to consume messages</li>
<pre class="prettyprint">
<code>connectionA.start();</code>
</pre>
<li>We consume messages from the session A, one at a time. We reached message no 5 the first server will crash</li>
<pre class="prettyprint">
<code>consume(sessionA, queue, numMessages, "A");</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>
if (connectionA != null)
{
connectionA.close();
}
if (initialContext != null)
{
initialContext.close();
}
</code>
</pre>
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