| <div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">Chapter 4. Examples</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="JMS-Client-0-8-JMS-Getting-And-Dependencies-Dependencies.html">Prev</a> </td><th align="center" width="60%"> </th><td align="right" width="20%"> <a accesskey="n" href="JMS-Client-0-8-Examples-PubSub.html">Next</a></td></tr></table><hr /></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a id="JMS-Client-0-8-Examples"></a>Chapter 4. Examples</h1></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="JMS-Client-0-8-Examples.html#JMS-Client-0-8-Examples-PTP">4.1. Point to point example</a></span></dt><dt><span class="section"><a href="JMS-Client-0-8-Examples-PubSub.html">4.2. Publish/subscribe example</a></span></dt></dl></div><p>The following programs shows how to send and receive messages using the Client. |
| The first program illustrates a <span class="emphasis"><em>point to point</em></span> example, the second, a |
| pubish/subscribe example. </p><p>Both examples show the use JNDI to obtain connection factory and destination objects which |
| the application needs. In this way the configuration is kept separate from the application |
| code itself.</p><p>The example code will be straightforward for anyone familiar with JMS. Readers in |
| need of an introduction are directed towards <a class="link" href="http://docs.oracle.com/javaee/6/tutorial/doc/bncdq.html" target="_top">Oracle's JMS |
| tutorial</a>.</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="JMS-Client-0-8-Examples-PTP"></a>4.1. Point to point example</h2></div></div></div><p>In this example, we illustrate point to point messaging. We create a JNDI context |
| using a properties file, use the context to lookup a connection factory, create and |
| start a connection, create a session, and lookup a destination (a queue) from the JNDI |
| context. Then we create a producer and a consumer, send a message with the producer and |
| receive it with the consumer.</p><div class="example"><a id="JMS-Client-0-8-Examples-PTP-Java"></a><p class="title"><strong>Example 4.1. JMS Example - Point to Point Messaging</strong></p><div class="example-contents"><pre class="programlisting"> |
| import javax.jms.*; |
| import javax.naming.Context; |
| import javax.naming.InitialContext; |
| import java.util.Properties; |
| |
| public class Hello { |
| |
| public Hello() { |
| } |
| |
| public static void main(String[] args) throws Exception { |
| Hello hello = new Hello(); |
| hello.runTest(); |
| } |
| |
| private void runTest() throws Exception { |
| Properties properties = new Properties(); |
| properties.load(this.getClass().getResourceAsStream("helloworld.properties")); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-properties" id="ptp-java-properties"><span><img alt="1" border="0" src="images/callouts/1.png" /></span></a> |
| Context context = new InitialContext(properties); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-context" id="ptp-java-context"><span><img alt="2" border="0" src="images/callouts/2.png" /></span></a> |
| |
| ConnectionFactory connectionFactory |
| = (ConnectionFactory) context.lookup("qpidConnectionFactory"); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-connection-factory" id="ptp-java-connection-factory"><span><img alt="3" border="0" src="images/callouts/3.png" /></span></a> |
| Connection connection = connectionFactory.createConnection(); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-connection" id="ptp-java-connection"><span><img alt="4" border="0" src="images/callouts/4.png" /></span></a> |
| connection.start(); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-start" id="ptp-java-start"><span><img alt="5" border="0" src="images/callouts/5.png" /></span></a> |
| |
| Session session = connection.createSession(true, Session.SESSION_TRANSACTED); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-session" id="ptp-java-session"><span><img alt="6" border="0" src="images/callouts/6.png" /></span></a> |
| Queue queue = (Queue) context.lookup("myqueue"); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-destination" id="ptp-java-destination"><span><img alt="7" border="0" src="images/callouts/7.png" /></span></a> |
| |
| MessageConsumer messageConsumer = session.createConsumer(queue); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-consumer" id="ptp-java-consumer"><span><img alt="8" border="0" src="images/callouts/8.png" /></span></a> |
| MessageProducer messageProducer = session.createProducer(queue); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-producer" id="ptp-java-producer"><span><img alt="9" border="0" src="images/callouts/9.png" /></span></a> |
| |
| TextMessage message = session.createTextMessage("Hello world!"); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-send" id="ptp-java-send"><span><img alt="10" border="0" src="images/callouts/10.png" /></span></a> |
| messageProducer.send(message); |
| session.commit(); |
| |
| message = (TextMessage)messageConsumer.receive(); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-receive" id="ptp-java-receive"><span><img alt="11" border="0" src="images/callouts/11.png" /></span></a> |
| session.commit(); |
| System.out.println(message.getText()); |
| |
| connection.close(); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-close" id="ptp-java-close"><span><img alt="12" border="0" src="images/callouts/12.png" /></span></a> |
| context.close(); <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-jndi-close" id="ptp-java-jndi-close"><span><img alt="13" border="0" src="images/callouts/13.png" /></span></a> |
| } |
| } |
| </pre></div></div><br class="example-break" /><div class="calloutlist"><table border="0" summary="Callout list"><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-properties"></a><a href="#ptp-java-properties"><span><img alt="1" border="0" src="images/callouts/1.png" /></span></a> </p></td><td align="left" valign="top"><p>Loads the JNDI properties file, which specifies the connection factory, queues |
| and topics. See <a class="xref" href="JMS-Client-0-8-JNDI-Properties-Format.html" title="Chapter 6. JNDI Properties Format">Chapter 6, <em>JNDI Properties Format</em></a> for |
| details.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-context"></a><a href="#ptp-java-context"><span><img alt="2" border="0" src="images/callouts/2.png" /></span></a> </p></td><td align="left" valign="top"><p>Creates the JNDI initial context.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-connection-factory"></a><a href="#ptp-java-connection-factory"><span><img alt="3" border="0" src="images/callouts/3.png" /></span></a> </p></td><td align="left" valign="top"><p>Looks up a JMS connection factory for Qpid.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-connection"></a><a href="#ptp-java-connection"><span><img alt="4" border="0" src="images/callouts/4.png" /></span></a> </p></td><td align="left" valign="top"><p>Creates a JMS connection. Creating the JMS connections establishes the |
| connection to the Broker.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-start"></a><a href="#ptp-java-start"><span><img alt="5" border="0" src="images/callouts/5.png" /></span></a> </p></td><td align="left" valign="top"><p>Starts the connection, required for the consumption of messages.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-session"></a><a href="#ptp-java-session"><span><img alt="6" border="0" src="images/callouts/6.png" /></span></a> </p></td><td align="left" valign="top"><p>Creates a transactional session.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-destination"></a><a href="#ptp-java-destination"><span><img alt="7" border="0" src="images/callouts/7.png" /></span></a> </p></td><td align="left" valign="top"><p>Looks up a destination for the queue with JNDI name <span class="emphasis"><em>myqueue</em></span>.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-consumer"></a><a href="#ptp-java-consumer"><span><img alt="8" border="0" src="images/callouts/8.png" /></span></a> </p></td><td align="left" valign="top"><p>Creates a consumer that reads messages from the queue<a class="footnote" href="#ftn.d0e197" id="d0e197"><sup class="footnote">[2]</sup></a>.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-producer"></a><a href="#ptp-java-producer"><span><img alt="9" border="0" src="images/callouts/9.png" /></span></a> </p></td><td align="left" valign="top"><p>Creates a producer that sends messages to the queue.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-send"></a><a href="#ptp-java-send"><span><img alt="10" border="0" src="images/callouts/10.png" /></span></a> </p></td><td align="left" valign="top"><p>Creates a new message of type <span class="emphasis"><em>javax.jms.TextMessage</em></span>, publishes the message and commits the |
| session.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-receive"></a><a href="#ptp-java-receive"><span><img alt="11" border="0" src="images/callouts/11.png" /></span></a> </p></td><td align="left" valign="top"><p>Reads the next available message (awaiting indefinitely if necessary) and |
| commits the session.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-close"></a><a href="#ptp-java-close"><span><img alt="12" border="0" src="images/callouts/12.png" /></span></a> </p></td><td align="left" valign="top"><p>Closes the Connection. All sessions owned by the Connection along with their |
| MessageConsumers and MessageProducers are automatically closed. The connection |
| to the Broker is closed as this point.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-jndi-close"></a><a href="#ptp-java-jndi-close"><span><img alt="13" border="0" src="images/callouts/13.png" /></span></a> </p></td><td align="left" valign="top"><p>Closes the JNDI context.</p></td></tr></table></div><p>The contents of the <code class="literal">helloworld.properties</code> file are shown |
| below.</p><div class="example"><a id="JMS-Client-0-8-Examples-PTP-PropertiesFile"></a><p class="title"><strong>Example 4.2. JMS Example - Point to Point Messaging - JNDI Properties</strong></p><div class="example-contents"><pre class="programlisting"> |
| java.naming.factory.initial = org.apache.qpid.jndi.PropertiesFileInitialContextFactory |
| connectionfactory.qpidConnectionFactory = amqp://guest:guest@clientid/?brokerlist='tcp://localhost:5672' <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-properties-connectionfactory" id="ptp-properties-connectionfactory"><span><img alt="1" border="0" src="images/callouts/1.png" /></span></a> |
| queue.myqueue = queue1 <a class="co" href="JMS-Client-0-8-Examples.html#callout-ptp-properties-destination" id="ptp-properties-destination"><span><img alt="2" border="0" src="images/callouts/2.png" /></span></a> |
| </pre></div></div><br class="example-break" /><div class="calloutlist"><table border="0" summary="Callout list"><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-properties-connectionfactory"></a><a href="#ptp-properties-connectionfactory"><span><img alt="1" border="0" src="images/callouts/1.png" /></span></a> </p></td><td align="left" valign="top"><p>Defines a connection factory from which Connections can be created. The syntax |
| of a ConnectionURL is given in <a class="xref" href="JMS-Client-0-8-Connection-URL.html" title="Chapter 7. Connection URLs">Chapter 7, <em>Connection URLs</em></a>.</p></td></tr><tr><td align="left" valign="top" width="5%"><p><a id="callout-ptp-properties-destination"></a><a href="#ptp-properties-destination"><span><img alt="2" border="0" src="images/callouts/2.png" /></span></a> </p></td><td align="left" valign="top"><p>Defines a queue for which MessageProducers and/or MessageConsumers send and |
| receive messages. The format of these entries is described in <a class="xref" href="JMS-Client-0-8-JNDI-Properties-Format-Queue.html" title="6.2. Queue">Section 6.2, “Queue”</a>.</p></td></tr></table></div></div><div class="footnotes"><br /><hr style="width:100; text-align:left;margin-left: 0" /><div class="footnote" id="ftn.d0e197"><p><a class="para" href="#d0e197"><sup class="para">[2] </sup></a>Creating consumer will automatically create the queue on the Broker |
| and bind it to an exchange. Specifically, in this case as the |
| <code class="literal">queue.</code> form is used in the JNDI properties the |
| effect will be to create a queue called <code class="literal">queue1</code> on the |
| Broker, and create a binding between the <code class="literal">amq.direct</code> |
| exchange and this queue using the queue's name. This process is |
| described in detail in <a class="xref" href="JMS-Client-0-8-Client-Understanding-MessageConsumer.html#JMS-Client-0-8-Client-Understanding-MessageConsumer-ConsumerSideEffect" title="5.6.1. Consumers have Exchange/Queue Declaration and Binding Side Effect">Section 5.6.1, “Consumers have Exchange/Queue Declaration and Binding Side Effect”</a></p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="JMS-Client-0-8-JMS-Getting-And-Dependencies-Dependencies.html">Prev</a> </td><td align="center" width="20%"> </td><td align="right" width="40%"> <a accesskey="n" href="JMS-Client-0-8-Examples-PubSub.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">3.2. Dependencies </td><td align="center" width="20%"><a accesskey="h" href="JMS-Client-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 4.2. Publish/subscribe example</td></tr></table></div></div> |
