<!--
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 Temporary Queue Example</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 Temporary Queue Example</h1>
<p>This example shows you how to use a TemporaryQueue with ActiveMQ. First a temporary queue is created to send and receive a message and then deleted.
Then another temporary queue is created and used after its connection is closed to illustrate its scope.</p>
<p>A TemporaryQueue is a JMS queue that exists only within the lifetime of its connection. It is often used in request-reply
type messaging where the reply is sent through a temporary destination. The temporary queue is often created as
a server resource, so after using, the user should call delete() method to release the resources.
Please consult the JMS 1.1 specification for full details.</p>
<h2>Example step-by-step</h2>
<p><i>To run the example, simply type <code>mvn verify</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 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 = getContext();</code>
</pre>
<li>We look-up JMS connection factory from JNDI</li>
<pre class="prettyprint">
<code>ConnectionFactory cf = (ConnectionFactory)initialContext.lookup("/ConnectionFactory");</code>
</pre>
<li>We Create a JMS connection</li>
<pre class="prettyprint">
<code>connection = cf.createConnection();</code>
</pre>
<li>We start the connection. In order for delivery to occur on any consumers or subscribers on a connection, the connection must be started</li>
<pre class="prettyprint">
<code>connection.start();</code>
</pre>
<li>We create a JMS session. The session is created as non transacted and will auto acknowledge messages.</li>
<pre class="prettyprint">
<code>Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>We create a Temporary Queue</li>
<pre class="prettyprint">
<code>Queue tempQueue = session.createTemporaryQueue();</code>
</pre>
<li>We create a JMS message producer to the temporary queue. This will be used to send the messages.</li>
<pre class="prettyprint">
<code>MessageProducer messageProducer = session.createProducer(tempQueue);</code>
</pre>
<li>We create a JMS text message to send </li>
<pre class="prettyprint">
<code>TextMessage message = session.createTextMessage("This is a text message");</code>
</pre>
<li>We send the message to the temporary queue</li>
<pre class="prettyprint">
<code>messageProducer.send(message);</code>
</pre>
<li>We create a message consumer of the temporary queue</li>
<pre class="prettyprint">
<code>MessageConsumer messageConsumer = session.createConsumer(tempQueue);</code>
</pre>
<li>We receive the message from the temporary queue</li>
<pre class="prettyprint">
<code>message = (TextMessage) messageConsumer.receive(5000);</code>
</pre>
<li>We close the consumer and producer before destroying the temporary queue</li>
<pre class="prettyprint">
<code>messageConsumer.close();</code>
<code>messageProducer.close();</code>
</pre>
<li>We delete the temporary queue</li>
<pre class="prettyprint">
<code>tempQueue.delete();</code>
</pre>
<li>We create another temporary queue</li>
<pre class="prettyprint">
<code>TemporaryQueue tempQueue2 = session.createTemporaryQueue();</code>
</pre>
<li>We close the connection</li>
<pre class="prettyprint">
<code>connection.close();</code>
</pre>
<li>We create a new connection</li>
<pre class="prettyprint">
<code>connection = cf.createConnection();</code>
</pre>
<li>We create a new session</li>
<pre class="prettyprint">
<code>session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
</pre>
<li>We try to access the tempQueue2 outside its lifetime, this will cause exception thrown</li>
<pre class="prettyprint">
<code>
try
{
messageConsumer = session.createConsumer(tempQueue2);
throw new Exception("Temporary queue cannot be accessed outside its lifecycle!");
}
catch (InvalidDestinationException e)
{
System.out.println("Exception got when trying to access a temp queue outside its scope: " + e);
}
</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 (connection != null)
{
connection.close();
}
}</code>
</pre>
</ol>
</body>
</html>
b00a0a99ab