<!--
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 Auto Closable 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 Auto Closable Example</h1>
<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>
<p>This example shows you how JMS resources, such as connections, sessions and consumers, in JMS 2 can be automatically closed on error.</p>
<p>In this instance we auto close a connection after a subsequent call to a JMS producer send fails</p>
<h2>Example step-by-step</h2>
<ol>
<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>
<pre class="prettyprint">
<code>InitialContext initialContext = getContext();</code>
</pre>
<li>We look-up the JMS queue object from JNDI</li>
<pre class="prettyprint">
<code>Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");</code>
</pre>
<li>We look-up the JMS connection factory object from JNDI</li>
<pre class="prettyprint">
<code>ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");</code>
</pre>
<li>We create a JMS context but we do it inside the try-with-resources statement like so:</li>
<pre class="prettyprint">
<code>
try
(
JMSContext jmsContext = cf.createContext()
)
</code>
</pre>
<li>Inside the following try block we first create the producer</li>
<pre class="prettyprint">
<code>JMSProducer jmsProducer = jmsContext.createProducer();</code>
</pre>
<li>We then try to send a message. It is this call that throws an exception as the producer doesn't have the privileges
to send a message</li>
<pre class="prettyprint">
<code>jmsProducer.send(queue, "this message will fail security!");</code>
</pre>
<li>We catch the exception from the send message and can do what we want, however the JMSContext will have been closed
prior to entering the catch block.</li>
<pre class="prettyprint">
<code>System.out.println("expected exception from jmsProducer.send: " + e.getMessage());</code>
</pre>
<li>And finally, we close the Initial Context, note we no longer have to worry about clearing up the JMSContext.</li>
<pre class="prettyprint">
<code>finally
{
if (initialContext != null)
{
initialContext.close();
}
}</code>
</pre>
</ol>
</body>
</html>
fdad83be22