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