4-16 Programming JMS for Oracle WebLogic Server
4.6.3 Dependency Injection
The following code fragment sends a message if you have used dependency injection to a variable.
Example 4–4 Sending a Message using Dependency Injection
package test; Example injected annotation.
import javax.annotation.Resource; import javax.ejb.;
import javax.jms.;
StatelessmappedName=StatelessBean public class MyStatelessBean implements MyStateless {
ResourcemappedName=myDestJNDIName private Destination dest;
ResourcemappedName=weblogic.jms.XAConnectionFactory private ConnectionFactory connectionFactory;
public void completeWorkOrder { Connection con = null;
Session session = null; MessageProducer sender = null;
try { System.out.printlncompleteWorkOrder called;
con = connectionFactory.createConnection; session = con.createSessiontrue, Session.AUTO_ACKNOWLEDGE;
sender = session.createProducernull; Message message = session.createTextMessagework order complete;
sender.senddest, message; } catchException e {
throw new EJBExceptionException sending message: + e, e; } finally {
try { if con = null con.close;
} catchException e { e.printStackTrace;
} }
} }
4.6.4 EJB 3.0 Wrapper Without Injection
This example demonstrates EJB 3.0 annotations for an MDB that references resources that are not injected. The references are resolved at runtime when the MDB is invoked
instead of when the MDB instances are instantiated.
Note: When using a wrapped JMS connection factory, which is
obtained by using the resource-ref feature and looked up by using the java:compenvjms JNDI tree context, then the EJB must not
use the javax.jms XA transactional XA interfaces.
Enhanced Support for Using WebLogic JMS with EJBs and Servlets 4-17
Example 4–5 Non-Injected MDB Example
package test; import javax.annotation.Resources;
import javax.annotation.Resource; import javax.naming.;
import javax.ejb.; import javax.jms.;
import javax.ejb.ActivationConfigProperty; MessageDriven
name = MyMDB, mappedName = JNDINameOfMDBSourceDest,
activationConfig = {
the JMS interface type for the MDB destination, either javax.jms.Topic or javax.jms.Queue
ActivationConfigProperty propertyName = destinationType,
propertyValue = javax.jms.Queue, optionally specify a connection factory
theres no need to specify a connection factory if the source destination is a WebLogic JMS destination
ActivationConfigProperty propertyName = connectionFactoryJndiName,
propertyValue = JNDINameOfMDBSourceCF, }
resources that are not injected Resources {
Resourcename=targetCFRef, mappedName=TargetCFJNDIName,
type=javax.jms.ConnectionFactory.class, Resourcename=targetDestRef,
mappedName=TargetDestJNDIName, type=javax.jms.Destination.class
} public class MyMDB implements MessageListener {
inject a reference to the MDB context Resource
private MessageDrivenContext mdctx; cache targetCF and targetDest for re-use performance
private ConnectionFactory targetCF; private Destination targetDest;
TransactionAttributeTransactionAttributeType.REQUIRED public void onMessageMessage message {
Connection jmsConnection = null; try {
4-18 Programming JMS for Oracle WebLogic Server
System.out.printlnMy MDB got message: + message; if targetCF == null
targetCF = javax.jms.ConnectionFactorymdctx.lookuptargetCFRef; if targetDest == null
targetDest = javax.jms.Destinationmdctx.lookuptargetDestRef; jmsConnection = targetCF.createConnection;
Session s = jmsConnection.createSessionfalse, Session.AUTO_ACKNOWLEDGE; MessageProducer mp = s.createProducernull;
if message.getJMSReplyTo = null mp.sendmessage.getJMSReplyTo, s.createTextMessageMy Reply;
else mp.sendtargetDest, message;
} catch JMSException e { throw new EJBExceptione;
} finally { Return JMS resources to the resource reference pool for later re-use.
Closing a connection automatically also closes its sessions, etc. try { if jmsConnection = null jmsConnection.close; }
catch JMSException ignored {}; }
} }
5
Developing a Basic JMS Application 5-1
5
Developing a Basic JMS Application
The following sections provide information on the steps required to develop a basic JMS application:
1.
Section 5.1, Importing Required Packages
2.
Section 5.2, Setting Up a JMS Application
3.
Section 5.3, Sending Messages
4.
Section 5.4, Receiving Messages
5.
Section 5.5, Acknowledging Received Messages
6.
Section 5.6, Releasing Object Resources In addition to the application development steps defined in the previous figure, you
can also optionally perform any of the following steps during your design development:
■
Manage connection and session processing
■
Create destinations dynamically
■
Create durable subscriptions
■
Manage message processing by setting and browsing message header and property fields, filtering messages, andor processing messages concurrently
■
Use JMS within transactions, described in Chapter 12, Using Transactions with
WebLogic JMS.
5.1 Importing Required Packages
The following table lists the packages that are commonly used by WebLogic JMS applications.
Note: For more information about the JMS classes described in this
section, access the JMS Javadoc supplied on the Sun Microsystems Java Web site at
http:www.java.sun.comproductsjmsdocs.html .
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