resin JMS Messaging in Quercus - Receiving messages tutorial display-ad.php
resin-web.xml configuration PHP script displaying the advertisement. Java listener that fills the advertisement queue. EJB Message bean configuration.

Quercus offers a simplified messaging interface built upon JMS. This functionality makes it possible to send and receive messages using either the Resin JMS implementation or any other messaging service with a JMS implementation. Many features of JMS are designed for message-driven services which make sense in the Java world, but are not appropriate for PHP. This tutorial focuses receiving messages in a non-blocking way.

This example uses two queues: an "ad queue" and a "control queue". The PHP script removes advertisements from the ad queue using the receive() method. This method is non-blocking - if there are no advertisements, the method will return FALSE instead of waiting for a new advertisement. Whenever the PHP script removes an advertisement from the ad queue, it signals a Java message driven bean (MDB) to add another ad by sending an empty message to the control queue.

$ad_queue = new JMSQueue("jms/AdQueue"); $control_queue = new JMSQueue("jms/ControlQueue"); if (! $ad_queue) { echo "Unable to get ad queue!\n"; } elseif (! $control_queue) { echo "Unable to get control queue!\n"; } else { $ad = $ad_queue->receive(); if ($ad == null) { echo "No ads available on the queue\n"; } else { echo "$ad"; } if (! $control_queue->send(0)) { echo "Unable to send control message\n"; } }

The programming model of the Quercus JMS interface is first to create a connection to a queue by instantiating a JMSQueue object. To create a JMSQueue object, pass in the JNDI name of the JMS queue to be used. JMSQueue objects have two methods: send() and receive(). The example above shows how to use both methods.

JMS requires that two resources be set up: A ConnectionFactory and a Queue. Both are configured in . The ConnectionFactory is used to connect to all the Queues and only one of them needs to be set up. The default JNDI name is jms/ConnectionFactory - Quercus automatically uses this connection factory. Another connection factory may be used by setting the PHP ini variable jms.connection_factory.

<resource jndi-name="jms/ConnectionFactory" type='com.caucho.jms.ConnectionFactoryImpl' />

This example uses two queues, jms/AdQueue and jms/ControlQueue.

<resource jndi-name="jms/AdQueue" type='com.caucho.jms.memory.MemoryQueue' /> <resource jndi-name="jms/ControlQueue" type='com.caucho.jms.memory.MemoryQueue' />

The complete configuration is in .