<!--
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 JMS Message Consumer Rate Limiting</title>
<link rel="stylesheet" type="text/css" href="../common/common.css" />
<link rel="stylesheet" type="text/css" href="../common/prettify.css" />
<script type="text/javascript" src="../common/prettify.js"></script>
</head>
<body onload="prettyPrint()">
<h1>JMS Message Consumer Rate Limiting</h1>
<p>With ActiveMQ you can specify a maximum consume rate at which a JMS MessageConsumer will consume messages.
This can be specified when creating or deploying the connection factory. See <code>activemq-jms.xml</code></p>
<p>If this value is specified then ActiveMQ will ensure that messages are never consumed at a rate higher than
the specified rate. This is a form of consumer <i>throttling</i>.</p>
<h2>Example step-by-step</h2>
<p>In this example we specify a <code>consumer-max-rate</code> of <code>10</code> messages per second in the <code>activemq-jms.xml</code>
file when deploying the connection factory:</p>
<pre class="prettyprint">
<code>
<connection-factory name="ConnectionFactory">
<connector-ref connector-name="netty-connector"/>
<entries>
<entry name="ConnectionFactory"/>
</entries>
<!-- We limit consumers created on this connection factory to consume messages at a maximum rate
of 10 messages per sec -->
<consumer-max-rate>50</producer-max-rate>
</connection-factory>
</code>
</pre>
<p>We then simply consume as many messages as we can in 10 seconds and note how many messages are actually consumed.</p>
<p>We note that the number of messages consumed per second never exceeds the specified value of <code>10</code> messages per second.</p>
<p><i>To run the example, simply type <code>mvn verify</code> from this directory</i></p>
<ol>
<li>Create an initial context to perform the JNDI lookup.</li>
<pre class="prettyprint">
<code>initialContext = getContext(0);</code>
</pre>
<li>Perfom a lookup on the queue</li>
<pre class="prettyprint">
<code>Queue queue = (Queue)initialContext.lookup("/queue/exampleQueue");</code>
</pre>
<li>Perform a lookup on the Connection Factory</li>
<pre class="prettyprint">
<code>ConnectionFactory cf = (ConnectionFactory)initialContext.lookup("/ConnectionFactory");</code>
</pre>
<li>Create a JMS Connection</li>
<pre class="prettyprint">
<code>connection = cf.createConnection();</code>
</pre>
<li>Create a JMS Session</li>
<pre class="prettyprint">
<code>Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>Create a JMS MessageProducer</li>
<pre class="prettyprint">
<code>MessageProducer producer = session.createProducer(queue);</code>
</pre>
<li>Create a JMS MessageConsumer</li>
<pre class="prettyprint">
<code>MessageConsumer consumer = session.createConsumer(queue);</code>
</pre>
<li>Start the connection</li>
<pre class="prettyprint">
<code>
connection.start();
</code>
</pre>
<li>Send a bunch of messages</li>
<pre class="prettyprint">
<code>
final int numMessages = 150;
for (int i = 0; i < numMessages; i++)
{
TextMessage message = session.createTextMessage("This is text message: " + i);
producer.send(message);
}
</code>
</pre>
<li>Consume as many messages as we can in 10 seconds</li>
<pre class="prettyprint">
<code>
final long duration = 10000;
int i = 0;
long start = System.currentTimeMillis();
while (System.currentTimeMillis() - start <= duration)
{
TextMessage message = (TextMessage)consumer.receive(2000);
if (message == null)
{
return false;
}
i++;
}
long end = System.currentTimeMillis();
double rate = 1000 * (double)i / (end - start);
System.out.println("We consumed " + i + " messages in " + (end - start) + " milliseconds");
System.out.println("Actual consume rate was " + rate + " messages per second");
</code>
</pre>
<li>This should produce output something like:</li>
<pre class="prettyprint">
<code>
[java] Sent messages
[java] Will now try and consume as many as we can in 10 seconds ...
[java] We consumed 100 messages in 10001 milliseconds
[java] Actual consume rate was 9.99900009999 messages per second
</code>
</pre>
<li>Be sure to close our resources!</li>
<pre class="prettyprint">
<code>
finally
{
if (initialContext != null)
{
initialContext.close();
}
if (connection != null)
{
connection.close();
}
}</code>
</pre>
</ol>
</body>
</html>
2b4e7babb6