EJB3 - where to perform JMS JNDI lookups?

Question

Hi, I was reading about how the WebLogic jms wrappers work at:
http://download.oracle.com/docs/cd/E12840_01/wls/docs103/jms/j2ee.html
and noticed this section:
"The JNDI lookups of the Connection Factory and Destination objects can be expensive in terms of performance. This is particularly true if the Destination object points to a Foreign JMS Destination MBean, and therefore, is a lookup on a non-local JNDI provider.". I am using Sonic MQ as my foreign JMS Provider hence this is of particular interest to me.
The document recommends caching these lookups in the ejbCreate() method of an EJB. I'm new to EJB3 but notice there is no concept of an ejbCreate() method there so where should I cache the lookups and how do I ensure they get re-looked up in the case of a connection failure?
Many thanks
Mandy

Answer 1

Thanks very much Tom, this helps a lot. I think my confusion lay in the fact that this document talks about caching the JNDI lookups in the ejbCreate and gives the example PoolTestBean.java which uses EJB2 style code. I've made your recommended changes to my code, would you mind just casting your eye over to see if looks ok? I have chosen to cache on create of the bean rather than on first invocation as I want clients to fail on startup rather than during their processing.
Sorry about code layout, not sure how to use HTML in posts to make it verbatim..
@Stateless
@TransactionAttribute(NEVER)
//@ExcludeDefaultInterceptors
public class ServiceWrapperBean implements ServiceWrapper {
     // injected resources
     @Resource
     private SessionContext sctx; // inject the bean context
     @Resource(name = "sonicConnectionFactory", mappedName = "sonic.connFactory", shareable = true)
     private ConnectionFactory connectionFactory;
     @Resource(name = "LegacyAccessIn", mappedName = "queue/LegacyIn", shareable = true)
     private Destination sendQueue;
     public void sendMessage(String msg) {
          if (connectionFactory == null)
               connectionFactory = (javax.jms.ConnectionFactory) sctx
                         .lookup("sonicConnectionFactory");
          if (sendQueue == null)
               sendQueue = (javax.jms.Destination) sctx.lookup("LegacyAccessIn");
          if (msg == null)
               throw new IllegalArgumentException("object cannot be null!");
          Connection con = null;
          Session session = null;
          MessageProducer sender = null;
          try {
               con = connectionFactory.createConnection();
               session = con.createSession(true, Session.AUTO_ACKNOWLEDGE);
               sender = session.createProducer(null);
               Message message = session.createTextMessage("do stuff");
               sender.send(sendQueue, message);
          } catch (JMSException e) {
               // Invalidate the JNDI objects if there is a failure
               // this is necessary because the destination object
               // may become invalid if the destination server has
               // been shut down
               connectionFactory = null;
               sendQueue = null;
               throw new RuntimeException(e);
          } finally {
               if (con != null) {
                    try {
                         // Return JMS resources to the resource reference pool for later re-use.
                         // Closing a connection automatically also closes its sessions, etc.
                         con.close(); // also closes other objects
                    } catch (JMSException je) {
                         // ignore
     }