<!--
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 JMS Clustered Grouping Example</title>
<link rel="stylesheet" type="text/css" href="../common/common.css">
</head>
<body>
<h1>JMS Clustered Grouping Example</h1>
<p>This example demonstrates how to ensure strict ordering across a cluster using clustered message grouping</p>
<p>We create 3 nodes each with a grouping message handler, one with a Local handler and 2 with a Remote handler.</p>
<p>The local handler acts as an arbitrator for the 2 remote handlers, holding the information on routes and communicating
the routing info with the remote handlers on the other 2 nodes</p>
<p>We then send some messages to each node with the same group id set and ensure the same consumer receives all of them</p>
<p>Here's the relevant snippet from the server configuration that has the local handler</p>
<pre>
<code>
<cluster-connections>
<cluster-connection name="my-cluster">
<address>jms</address>
<connector-ref>netty-connector</connector-ref>
<retry-interval>500</retry-interval>
<use-duplicate-detection>true</use-duplicate-detection>
<forward-when-no-consumers>true</forward-when-no-consumers>
<max-hops>1</max-hops>
<discovery-group-ref discovery-group-name="my-discovery-group"/>
</cluster-connection>
</cluster-connections>
<grouping-handler name="my-grouping-handler">
<type>LOCAL</type>
<address>jms</address>
<timeout>5000</timeout>
</grouping-handler>
</code>
</pre>
<p>Here's the relevant snippet from the server configuration that has the remote handlers</p>
<pre>
<code>
<cluster-connections>
<cluster-connection name="my-cluster">
<address>jms</address>
<retry-interval>500</retry-interval>
<use-duplicate-detection>true</use-duplicate-detection>
<forward-when-no-consumers>true</forward-when-no-consumers>
<max-hops>1</max-hops>
<discovery-group-ref discovery-group-name="my-discovery-group"/>
</cluster-connection>
</cluster-connections>
<grouping-handler name="my-grouping-handler">
<type>REMOTE</type>
<address>jms</address>
<timeout>5000</timeout>
</grouping-handler>
</code>
</pre>
<p>For more information on ActiveMQ Artemis clustering and grouping see the clustering and grouping
section of 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> Get an initial context for looking up JNDI from server 0.</li>
<pre class="prettyprint">
<code>ic0 = getContext(0);</code>
</pre>
<li>Look-up the JMS Queue object from JNDI</li>
<pre class="prettyprint">
<code>Queue queue = (Queue)ic0.lookup("/queue/exampleQueue");</code>
</pre>
<li>Look-up a JMS Connection Factory object from JNDI on server 0</li>
<pre class="prettyprint">
<code>ConnectionFactory cf0 = (ConnectionFactory)ic0.lookup("/ConnectionFactory");</code>
</pre>
<li>Get an initial context for looking up JNDI from server 1.</li>
<pre class="prettyprint">
<code>ic1 = getContext(1);</code>
</pre>
<li>Look-up a JMS Connection Factory object from JNDI on server 1</li>
<pre class="prettyprint">
<code>ConnectionFactory cf1 = (ConnectionFactory)ic1.lookup("/ConnectionFactory");
</code>
</pre>
<li>Get an initial context for looking up JNDI from server 2.</li>
<pre class="prettyprint">
<code>ic2 = getContext(2);</code>
</pre>
<li>Look-up a JMS Connection Factory object from JNDI on server 2</li>
<pre class="prettyprint">
<code>ConnectionFactory cf2 = (ConnectionFactory)ic2.lookup("/ConnectionFactory");
</code>
</pre>
<li>We create a JMS Connection connection0 which is a connection to server 0</li>
<pre class="prettyprint">
<code>connection0 = cf0.createConnection();</code>
</pre>
<li>We create a JMS Connection connection0 which is a connection to server 1</li>
<pre class="prettyprint">
<code>connection1 = cf1.createConnection();</code>
</pre>
<li>We create a JMS Connection connection0 which is a connection to server 2</li>
<pre class="prettyprint">
<code>connection2 = cf2.createConnection();</code>
</pre>
<li>We create a JMS Session on server 0</li>
<pre class="prettyprint">
<code>Session session0 = connection0.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>We create a JMS Session on server 1</li>
<pre class="prettyprint">
<code>Session session1 = connection1.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>We create a JMS Session on server 2</li>
<pre class="prettyprint">
<code>Session session2 = connection2.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>We start the connections to ensure delivery occurs on them</li>
<pre class="prettyprint">
<code>
connection0.start();
connection1.start();
connection2.start();</code>
</pre>
<li>We create JMS MessageConsumer objects on server 0</li>
<pre class="prettyprint">
<code>MessageConsumer consumer = session0.createConsumer(queue);</code>
</pre>
<li>We create a JMS MessageProducer object on server 0, 1 and 2</li>
<pre class="prettyprint">
<code>
MessageProducer producer0 = session0.createProducer(queue);
MessageProducer producer1 = session1.createProducer(queue);
MessageProducer producer2 = session2.createProducer(queue);</code>
</pre>
<li>We send some messages to server 0, 1 and 2 with the same groupid set</li>
<pre class="prettyprint">
<code>
final int numMessages = 10;
for (int i = 0; i < numMessages; i++)
{
TextMessage message = session0.createTextMessage("This is text message " + i);
message.setStringProperty(ActiveMQMessage.JMSXGROUPID, "Group-0");
producer0.send(message);
System.out.println("Sent messages: " + message.getText() + " to node 0");
}
for (int i = 0; i < numMessages; i++)
{
TextMessage message = session1.createTextMessage("This is text message " + (i + 10));
message.setStringProperty(ActiveMQMessage.JMSXGROUPID, "Group-0");
producer1.send(message);
System.out.println("Sent messages: " + message.getText() + " to node 1");
}
for (int i = 0; i < numMessages; i++)
{
TextMessage message = session2.createTextMessage("This is text message " + (i + 20));
message.setStringProperty(ActiveMQMessage.JMSXGROUPID, "Group-0");
producer2.send(message);
System.out.println("Sent messages: " + message.getText() + " to node 2");
}
</code>
</pre>
<li>We now consume those messages from server 0. We note the messages have all been sent to the same consumer on the same node</li>
<pre class="prettyprint">
<code>
for (int i = 0; i < numMessages * 3; i++)
{
TextMessage message0 = (TextMessage)consumer.receive(5000);
System.out.println("Got message: " + message0.getText() + " from node 0");
}
</code>
</pre>
<li>Finally, Be sure to close our resources!</li>
<pre class="prettyprint">
<code>
if (connection0 != null)
{
connection0.close();
}
if (connection1 != null)
{
connection1.close();
}
if (connection2 != null)
{
connection2.close();
}
if (ic0 != null)
{
ic0.close();
}
if (ic1 != null)
{
ic1.close();
}
if (ic2 != null)
{
ic2.close();
}</code>
</pre>
</ol>
</body>
</html>
97210427df