67 lines
3.7 KiB
HTML
67 lines
3.7 KiB
HTML
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<html>
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<head>
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<title>ActiveMQ Artemis JMS Durable Subscription 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>JMS Durable Subscription Example</h1>
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<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>
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<p>This example demonstrates a clustered JMS durable subscription.
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Normally durable subscriptions exist on a single node and can only have one subscriber at any one time,
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however, with ActiveMQ Artemis it's possible to create durable subscription instances with the same name and client-id
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on different nodes of the cluster, and consume from them simultaneously.
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This allows the work of processing messages from a durable subscription to be spread across the cluster in
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a similar way to how JMS Queues can be load balanced across the cluster
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</p>
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<p>In this example we first configure the two nodes to form a cluster, then we then create a durable subscriber
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with the same name and client-id on both nodes, and we create a producer on only one of the nodes.</p>
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<p>We then send some messages via the producer, and we verify that the messages are round robin'd between
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the two subscription instances. Note that each durable subscription instance with the same name and client-id
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<b>does not</b> receive its own copy of the messages. This is because the instances on different nodes form a
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single "logical" durable subscription, in the same way multiple JMS Queue instances on different nodes
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form a single "local" JMS Queue</p>
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<p>This example uses JNDI to lookup the JMS Queue and ConnectionFactory objects. If you prefer not to use
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JNDI, these could be instantiated directly.
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<p>Here's the relevant snippet from the server configuration, which tells the server to form a cluster between the two nodes
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and to load balance the messages between the nodes.</p>
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<p>The cli create method will define this section by default if you use --clustered as a parameter</p>
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<pre class="prettyprint">
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<code><cluster-connection name="my-cluster">
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<address>jms</address>
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<retry-interval>500</retry-interval>
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<use-duplicate-detection>true</use-duplicate-detection>
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<message-load-balancing>STRICT</message-load-balancing>
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<max-hops>1</max-hops>
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<discovery-group-ref discovery-group-name="my-discovery-group"/>
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</cluster-connection>
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</code>
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</pre>
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<p>For more information on ActiveMQ Artemis load balancing, and clustering in general, please see the clustering
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section of the user manual.</p>
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</body>
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</html>
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