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<title>ActiveMQ JMS Completion Listener Example</title>
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<h1>JMS Completion Listener Example</h1>
<p>This example shows you how to send a message asynchronously to ActiveMQ and use a CompletionListener to be notified of
the Broker receiving it</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>
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<code>Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");</code>
</pre>
<li>We look-up the JMS connection factory object from JNDI</li>
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<code>ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");</code>
</pre>
<li>We create a JMS context</li>
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<code>jmsContext = cf.createContext();</code>
</pre>
<li>We create a JMS Producer.</li>
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<code>JMSProducer producer = jmsContext.createProducer();</code>
</pre>
<li>We set a CompletionListener on the Producer</li>
<pre class="prettyprint">
<code>producer.setAsync(new CompletionListener()
{
@Override
public void onCompletion(Message message)
{
System.out.println("message acknowledged by ActiveMQ");
latch.countDown();
}
@Override
public void onException(Message message, Exception e)
{
e.printStackTrace();
}
});</code>
</pre>
<li>We send a message</li>
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<code>producer.send(queue, "this is a string");</code>
</pre>
<li> and then wait for the Completion Listener to be called</li>
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<code>return latch.await(5, TimeUnit.SECONDS);</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 (jmsContext != null)
{
jmsContext.close();
}
}</code>
</pre>
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