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<title>ActiveMQ JMS Instantiate Connection Factory Example</title>
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<h1>JMS Instantiate Connection Factory Example</h1>
<p>Usually, JMS Objects such as ConnectionFactories, Queue and Topic instances are looked up from JNDI
before being used by the client code. This objects are called "administered objects" in JMS specification
terminology.</p>
<p>However, in some cases a JNDI server may not be available or desired. To come to the rescue ActiveMQ
also supports the direct instantiation of these administered objects on the client side.</p>
<p>This allows the full set of JMS functionality to be available without requiring a JNDI server!</p>
<p>This example is very simple and based on the simple Queue example, however in this example we
instantiate the JMS Queue and ConnectionFactory objects directly.</p>
<p>A wide variety of methods are available for instantiating ConnectionFactory objects. In this example
we use a simple method which just takes the server connection details so it knows where to make the
connection to.</p>
<p>Other methods are available so all the connection factory parameters can be specified
including specifying UDP discovery so the client does not need hard-wired knowledge of where the servers
are that it wishes to connect to, or for specifying live-backup pairs of servers for failover.</p>
<p>For more information on instantiating ConnectionFactories directly please consult the user manual and
javadoc.</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>Instead of looking it up from JNDI we directly instantiate the JMS Queue object. We
pass in the name of the JMS Queue in the constructor. The actual JMS Queue must already be deployed on
the server.</li>
<pre class="prettyprint">
<code>
Queue queue = new ActiveMQQueue("exampleQueue");</code>
</pre>
<li>Instantiate the TransportConfiguration object. The TransportConfiguration instance encapsulates
the connection details of the server we're connecting to. In this case we're using Netty as a transport, and
we're specifying to connect on port 5446.</li>
<pre class="prettyprint">
<code>
Map<String, Object> connectionParams = new HashMap<String, Object>();
connectionParams.put(PORT_PROP_NAME, 5446);
TransportConfiguration transportConfiguration = new TransportConfiguration(NettyConnectorFactory.class.getName(),
connectionParams);
</code>
</pre>
<li>Directly instantiate the JMS ConnectionFactory object using that TransportConfiguration.</li>
<pre class="prettyprint">
<code>
ConnectionFactory cf = ActiveMQJMSClient.createConnectionFactoryWithoutHA(transportConfiguration);
</code>
</pre>
<li>We create a JMS connection</li>
<pre class="prettyprint">
<code>connection = cf.createConnection();</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 JMS message producer on the session. This will be used to send the messages.</li>
<pre class="prettyprint">
<code>MessageProducer messageProducer = session.createProducer(topic);</code>
</pre>
<li>We create a JMS text message that we are going to send.</li>
<pre class="prettyprint">
<code>TextMessage message = session.createTextMessage("This is a text message");</code>
</pre>
<li>We send message to the queue</li>
<pre class="prettyprint">
<code>messageProducer.send(message);</code>
</pre>
<li>We create a JMS Message Consumer to receive the message.</li>
<pre class="prettyprint">
<code>MessageConsumer messageConsumer = session.createConsumer(queue);</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>The message arrives at the consumer. In this case we use a timeout of 5000 milliseconds but we could use a blocking 'receive()'</li>
<pre class="prettyprint">
<code>TextMessage messageReceived = (TextMessage) messageConsumer.receive(5000);</code>
</pre>
<li>And finally, <b>always</b> remember to close your resources after use, in a <code>finally</code> block.</li>
<pre class="prettyprint">
<code>finally
{
if (connection != null)
{
connection.close();
}
}</code>
</pre>
</ol>
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