Oracle Java Message Service Shared Interfaces

15 Oracle Java Message Service Shared Interfaces

The following topics describe the Java Message Service (JMS) operational interface (shared interfaces) to Oracle Database Advanced Queuing (AQ).

Oracle Database Advanced Queuing JMS Operational Interface: Shared Interfaces

The following topics discuss Oracle Database Advanced Queuing shared interfaces for JMS operations.

Starting a JMS Connection

public void start()
          throws JMSException

AQjmsConnection.start() starts a JMS connection for receiving messages.

Getting a JMS Connection

public oracle.jms.AQjmsConnection getJmsConnection()
                                            throws JMSException

AQjmsSession.getJmsConnection() gets a JMS connection from a session.

Committing All Operations in a Session

public void commit()
           throws JMSException

AQjmsSession.commit() commits all JMS and SQL operations performed in a session.

Rolling Back All Operations in a Session

public void rollback()
              throws JMSException

AQjmsSession.rollback() terminates all JMS and SQL operations performed in a session.

Getting the JDBC Connection from a Session

public java.sql.Connection getDBConnection()
                                    throws JMSException

AQjmsSession.getDBConnection() gets the underlying JDBC connection from a JMS session. The JDBC connection can be used to perform SQL operations as part of the same transaction in which the JMS operations are accomplished.

Example 15-1 Getting Underlying JDBC Connection from JMS Session

java.sql.Connection db_conn;
QueueSession     jms_sess;
db_conn = ((AQjmsSession)jms_sess).getDBConnection();

Getting the OracleOCIConnectionPool from a JMS Connection

public oracle.jdbc.pool.OracleOCIConnectionPool getOCIConnectionPool()

AQjmsConnection.getOCIConnectionPool() gets the underlying OracleOCIConnectionPool from a JMS connection. The settings of the OracleOCIConnectionPool instance can be tuned by the user depending on the connection usage, for example, the number of sessions the user wants to create using the given connection. The user should not, however, close the OracleOCIConnectionPool instance being used by the JMS connection.

Example 15-2 Getting Underlying OracleOCIConnectionPool from JMS Connection

oracle.jdbc.pool.OracleOCIConnectionPool cpool;
QueueConnection jms_conn;
cpool = ((AQjmsConnection)jms_conn).getOCIConnectionPool();

Creating a BytesMessage

public javax.jms.BytesMessage createBytesMessage()
                                          throws JMSException

AQjmsSession.createBytesMessage() creates a bytes message. It can be used only if the queue table that contains the destination queue/topic was created with the SYS.AQ$_JMS_BYTES_MESSAGE or AQ$_JMS_MESSAGE payload types.

Creating a MapMessage

public javax.jms.MapMessage createMapMessage()
                                      throws JMSException

AQjmsSession.createMapMessage() creates a map message. It can be used only if the queue table that contains the destination queue/topic was created with the SYS.AQ$_JMS_MAP_MESSAGE or AQ$_JMS_MESSAGE payload types.

Creating a StreamMessage

public javax.jms.StreamMessage createStreamMessage()
                                            throws JMSException

AQjmsSession.createStreamMessage() creates a stream message. It can be used only if the queue table that contains the destination queue/topic was created with the SYS.AQ$_JMS_STREAM_MESSAGE or AQ$_JMS_MESSAGE payload types.

Creating an ObjectMessage

public javax.jms.ObjectMessage createObjectMessage(java.io.Serializable object)
                                            throws JMSException

AQjmsSession.createObjectMessage() creates an object message. It can be used only if the queue table that contains the destination queue/topic was created with the SYS.AQ$_JMS_OBJECT_MESSAGE or AQ$_JMS_MESSAGE payload types.

Creating a TextMessage

public javax.jms.TextMessage createTextMessage()
                                        throws JMSException

AQjmsSession.createTextMessage() creates a text message. It can be used only if the queue table that contains the destination queue/topic was created with the SYS.AQ$_JMS_TEXT_MESSAGE or AQ$_JMS_MESSAGE payload types.

Creating a JMS Message

public javax.jms.Message createMessage()
                                throws JMSException

AQjmsSession.createMessage() creates a JMS message. You can use the AQ$_JMS_MESSAGE construct message to construct messages of different types. The message type must be one of the following:

DBMS_AQ.JMS_TEXT_MESSAGE
DBMS_AQ.JMS_OBJECT_MESSAGE
DBMS_AQ.JMS_MAP_MESSAGE
DBMS_AQ.JMS_BYTES_MESSAGE
DBMS_AQ.JMS_STREAM_MESSAGE

You can also use this ADT to create a header-only JMS message.

Creating an AdtMessage

public oracle.jms.AdtMessage createAdtMessage()
                                       throws JMSException

AQjmsSession.createAdtMessage() creates an AdtMessage. It can be used only if the queue table that contains the queue/topic was created with an Oracle ADT payload type. An AdtMessage must be populated with an object that implements the CustomDatum interface. This object must be the Java mapping of the SQL ADT defined as the payload for the queue/topic. Java classes corresponding to SQL ADT types can be generated using the Jpublisher tool.

Setting a JMS Correlation Identifier

public void setJMSCorrelationID(java.lang.String correlationID)
                         throws JMSException

AQjmsMessage.setJMSCorrelationID() specifies the message correlation identifier.

Specifying JMS Message Properties

Property names starting with JMS are provider-specific. User-defined properties cannot start with JMS.

The following provider properties can be set by clients using text, stream, object, bytes or map messages:

JMSXAppID (string)
JMSXGroupID (string)
JMSXGroupSeq (int)
JMS_OracleExcpQ (string)

This message property specifies the exception queue.
JMS_OracleDelay (int)

This message property specifies the message delay in seconds.

The following properties can be set on AdtMessage

JMS_OracleExcpQ (String)

This message property specifies the exception queue as "schema.queue_name"
JMS_OracleDelay (int)

This message property specifies the message delay in seconds.

This section contains these topics:

Setting a Boolean Message Property

public void setBooleanProperty(java.lang.String name,
                               boolean value)
                        throws JMSException

AQjmsMessage.setBooleanProperty() specifies a message property as Boolean. It has the following parameters:

Parameter	Description
`name`	Name of the Boolean property
`value`	Boolean property value to set in the message

Setting a String Message Property

public void setStringProperty(java.lang.String name,
                              java.lang.String value)
                       throws JMSException

AQjmsMessage.setStringProperty() specifies a message property as string. It has the following parameters:

Parameter	Description
`name`	Name of the string property
`value`	String property value to set in the message

Setting an Integer Message Property

public void setIntProperty(java.lang.String name,
                           int value)
                    throws JMSException

AQjmsMessage.setIntProperty() specifies a message property as integer. It has the following parameters:

Parameter	Description
`name`	Name of the integer property
`value`	Integer property value to set in the message

Setting a Double Message Property

public void setDoubleProperty(java.lang.String name,
                              double value)
                       throws JMSException

AQjmsMessage.setDoubleProperty() specifies a message property as double. It has the following parameters:

Parameter	Description
`name`	Name of the double property
`value`	Double property value to set in the message

Setting a Float Message Property

public void setFloatProperty(java.lang.String name,
                             float value)
                      throws JMSException

AQjmsMessage.setFloatProperty() specifies a message property as float. It has the following parameters:

Parameter	Description
`name`	Name of the float property
`value`	Float property value to set in the message

Setting a Byte Message Property

public void setByteProperty(java.lang.String name,
                            byte value)
                     throws JMSException

AQjmsMessage.setByteProperty() specifies a message property as byte. It has the following parameters:

Parameter	Description
`name`	Name of the byte property
`value`	Byte property value to set in the message

Setting a Long Message Property

public void setLongProperty(java.lang.String name,
                            long value)
                     throws JMSException

AQjmsMessage.setLongProperty() specifies a message property as long. It has the following parameters:

Parameter	Description
`name`	Name of the long property
`value`	Long property value to set in the message

Setting a Short Message Property

public void setShortProperty(java.lang.String name,
                             short value)
                      throws JMSException

AQjmsMessage.setShortProperty() specifies a message property as short. It has the following parameters:

Parameter	Description
`name`	Name of the short property
`value`	Short property value to set in the message

Setting an Object Message Property

public void setObjectProperty(java.lang.String name,
                              java.lang.Object value)
                       throws JMSException

AQjmsMessage.setObjectProperty() specifies a message property as object. Only objectified primitive values are supported: Boolean, byte, short, integer, long, float, double and string. It has the following parameters:

Parameter	Description
`name`	Name of the Java object property
`value`	Java object property value to set in the message

Setting Default TimeToLive for All Messages Sent by a MessageProducer

public void setTimeToLive(long timeToLive)
                   throws JMSException

This method sets the default TimeToLive for all messages sent by a MessageProducer. It is calculated after message delay has taken effect. This method has the following parameter:

Parameter	Description
`timeToLive`	Message time to live in milliseconds (zero is unlimited)

Example 15-3 Setting Default TimeToLive for All Messages Sent by a MessageProducer

/* Set default timeToLive value to 100000 milliseconds for all messages sent by the QueueSender*/
QueueSender sender;
sender.setTimeToLive(100000);

Setting Default Priority for All Messages Sent by a MessageProducer

public void setPriority(int priority)
                 throws JMSException

This method sets the default Priority for all messages sent by a MessageProducer. It has the following parameter:

Parameter	Description
`priority`	Message priority for this message producer. The default is 4.

Priority values can be any integer. A smaller number indicates higher priority. If a priority value is explicitly specified during a send() operation, then it overrides the default value set by this method.

Example 15-4 Setting Default Priority Value for All Messages Sent by QueueSender

/* Set default priority value to 2 for all messages sent by the QueueSender*/
QueueSender sender;
sender.setPriority(2);

Example 15-5 Setting Default Priority Value for All Messages Sent by TopicPublisher

/* Set default priority value to 2 for all messages sent by the TopicPublisher*/
TopicPublisher publisher;
publisher.setPriority(1);

Creating an AQjms Agent

public void createAQAgent(java.lang.String agent_name,
                          boolean enable_http,
                   throws JMSException

This method creates an AQjmsAgent. It has the following parameters:

Parameter	Description
`agent_name`	Name of the AQ agent
`enable_http`	If set to true, then this agent is allowed to access AQ through HTTP

Receiving a Message Synchronously

You can receive a message synchronously by specifying Timeout or without waiting. You can also receive a message using a transformation:

Using a Message Consumer by Specifying Timeout

public javax.jms.Message receive(long timeout)
                          throws JMSException

This method receives a message using a message consumer by specifying timeout.

Parameter	Description
`timeout`	Timeout value in milliseconds

Example 15-6 Using a Message Consumer by Specifying Timeout

TopicConnectionFactory    tc_fact   = null;
TopicConnection           t_conn    = null;
TopicSession              t_sess    = null;
TopicSession              jms_sess;
Topic                     shipped_orders;
int                       myport = 5521;

/* create connection and session */
tc_fact = AQjmsFactory.getTopicConnectionFactory(
   "MYHOSTNAME", "MYSID", myport, "oci8");
t_conn = tc_fact.createTopicConnection("jmstopic", "jmstopic");
jms_sess = t_conn.createTopicSession(true, Session.CLIENT_ACKNOWLEDGE);
shipped_orders = ((AQjmsSession )jms_sess).getTopic(
   "WS", "Shipped_Orders_Topic");

/* create a subscriber, specifying the correct CustomDatumFactory  and
selector */
subscriber1 = jms_sess.createDurableSubscriber(
   shipped_orders, 'WesternShipping', 
   " priority > 1 and tab.user_data.region like 'WESTERN %'",
   false, AQjmsAgent.getFactory());
/* receive, blocking for 30 seconds if there were no messages */
Message = subscriber.receive(30000);

Example 15-7 JMS: Blocking Until a Message Arrives

public BolOrder get_new_order1(QueueSession jms_session)
 {
   Queue            queue;
   QueueReceiver    qrec;
   ObjectMessage    obj_message;
   BolCustomer      customer;
   BolOrder         new_order = null;
   String           state;

   try
   {
   /* get a handle to the new_orders queue */
    queue = ((AQjmsSession) jms_session).getQueue("OE", "OE_neworders_que");
    qrec = jms_session.createReceiver(queue);

    /* wait for a message to show up in the queue */
    obj_message = (ObjectMessage)qrec.receive();
    new_order = (BolOrder)obj_message.getObject();
    customer = new_order.getCustomer();
    state    = customer.getState();
    System.out.println("Order:  for customer " + customer.getName()); 
   }
  catch (JMSException ex)
   {
     System.out.println("Exception: " + ex);
   }
   return new_order;
 }

Using a Message Consumer Without Waiting

public javax.jms.Message receiveNoWait()
                                throws JMSException

This method receives a message using a message consumer without waiting.

Example 15-8 JMS: Nonblocking Messages

public BolOrder poll_new_order3(QueueSession jms_session)
 {
   Queue            queue;
   QueueReceiver    qrec;
   ObjectMessage    obj_message;
   BolCustomer      customer;
   BolOrder         new_order = null;
   String           state;

   try
   {
    /* get a handle to the new_orders queue */
    queue = ((AQjmsSession) jms_session).getQueue("OE", "OE_neworders_que");
    qrec = jms_session.createReceiver(queue);

    /* check for a message to show in the queue */
    obj_message = (ObjectMessage)qrec.receiveNoWait();
    new_order = (BolOrder)obj_message.getObject();
    customer = new_order.getCustomer();
    state    = customer.getState();

    System.out.println("Order:  for customer " + customer.getName()); 
   }
   catch (JMSException ex)
   {
     System.out.println("Exception: " + ex);
   }
   return new_order;
 }

Receiving Messages from a Destination Using a Transformation

A transformation can be applied when receiving a message from a queue or topic. The transformation is applied to the message before returning it to JMS application.

The transformation can be specified using the setTransformation() interface of the AQjmsQueueReceiver, AQjmsTopicSubscriber or AQjmsTopicReceiver.

Example 15-9 JMS: Receiving Messages from a Destination Using a Transformation

Assume that the Western Shipping application retrieves messages from the OE_bookedorders_topic. It specifies the transformation OE2WS to retrieve the message as the Oracle object type WS_order. Assume that the WSOrder Java class has been generated by Jpublisher to map to the Oracle object WS.WS_order:

public AQjmsAdtMessage retrieve_bookedorders(TopicSession jms_session)
  AQjmsTopicReceiver  receiver;
  Topic               topic;
  Message             msg = null;

  try
  {
    /* get a handle to the OE_bookedorders_topic */
    topic = ((AQjmsSession)jms_session).getTopic("OE", "OE_bookedorders_topic");

    /* Create a receiver for WShip */
    receiver = ((AQjmsSession)jms_session).createTopicReceiver(
       topic, "WShip, null, WSOrder.getFactory());

    /* set the transformation in the publisher */
    receiver.setTransformation("OE2WS");
    msg = receiver.receive(10);
  }
  catch (JMSException ex)
  {
     System.out.println("Exception :", ex);
  }
       return (AQjmsAdtMessage)msg;
}

Specifying the Navigation Mode for Receiving Messages

public void setNavigationMode(int mode)
                       throws JMSException

This method specifies the navigation mode for receiving messages. It has the following parameter:

Parameter	Description
`mode`	New value of the navigation mode

Example 15-10 Specifying Navigation Mode for Receiving Messages

TopicConnectionFactory    tc_fact   = null;
TopicConnection           t_conn    = null;
TopicSession              t_sess    = null;
TopicSession              jms_sess;
Topic                     shipped_orders;
int                       myport = 5521;

/* create connection and session */
tc_fact = AQjmsFactory.getTopicConnectionFactory(
   "MYHOSTNAME", "MYSID", myport, "oci8");
t_conn = tc_fact.createTopicConnection("jmstopic", "jmstopic");
jms_sess = t_conn.createTopicSession(true, Session.CLIENT_ACKNOWLEDGE);
shipped_orders = ((AQjmsSession )jms_sess).getTopic("WS", "Shipped_Orders_Topic");

/* create a subscriber, specifying the correct CustomDatumFactory and selector */
subscriber1 = jms_sess.createDurableSubscriber(
   shipped_orders, 'WesternShipping', 
   "priority > 1 and tab.user_data.region like 'WESTERN %'", false,
   AQjmsAgent.getFactory());
subscriber1.setNavigationMode(AQjmsConstants.NAVIGATION_FIRST_MESSAGE);

/* get message for the subscriber, returning immediately if there was nomessage */
Message = subscriber.receive();

Receiving a Message Asynchronously

You can receive a message asynchronously two ways:

Specifying a Message Listener at the Message Consumer

public void setMessageListener(javax.jms.MessageListener myListener)
                        throws JMSException

This method specifies a message listener at the message consumer. It has the following parameter:

Parameter	Description
`myListener`	Sets the consumer message listener

Example 15-11 Specifying Message Listener at Message Consumer

TopicConnectionFactory    tc_fact   = null;
TopicConnection           t_conn    = null;
TopicSession              t_sess    = null;
TopicSession              jms_sess;
Topic                     shipped_orders;
int                       myport = 5521;
MessageListener           mLis = null;

/* create connection and session */
tc_fact = AQjmsFactory.getTopicConnectionFactory(
   "MYHOSTNAME", "MYSID", myport, "oci8");
t_conn = tc_fact.createTopicConnection("jmstopic", "jmstopic");
jms_sess = t_conn.createTopicSession(true, Session.CLIENT_ACKNOWLEDGE);
shipped_orders = ((AQjmsSession )jms_sess).getTopic(
    "WS", "Shipped_Orders_Topic");

/* create a subscriber, specifying the correct CustomDatumFactory and selector */
subscriber1 = jms_sess.createDurableSubscriber(
   shipped_orders, 'WesternShipping',
   "priority > 1 and tab.user_data.region like 'WESTERN %'",
   false, AQjmsAgent.getFactory());
mLis = new myListener(jms_sess, "foo");

/* get message for the subscriber, returning immediately if there was nomessage */
subscriber.setMessageListener(mLis);
The definition of the myListener class
import oracle.AQ.*;
import oracle.jms.*;
import javax.jms.*;
import java.lang.*;
import java.util.*;
public class myListener implements MessageListener
{
   TopicSession   mySess;
   String         myName;
   /* constructor */
   myListener(TopicSession t_sess, String t_name)
   {
      mySess = t_sess;
      myName = t_name;
   }
   public onMessage(Message m)
   {
      System.out.println("Retrieved message with correlation: " ||
m.getJMSCorrelationID());
      try{
        /* commit the dequeue */
        mySession.commit();
      } catch (java.sql.SQLException e)
      {System.out.println("SQL Exception on commit"); }
   }
}

Specifying a Message Listener at the Session

public void setMessageListener(javax.jms.MessageListener listener)
                        throws JMSException

This method specifies a message listener at the session.

Parameter	Description
`listener`	Message listener to associate with this session

Getting Message ID

This section contains these topics:

Getting the Correlation Identifier

public java.lang.String getJMSCorrelationID()
          throws JMSException

AQjmsMessage.getJMSCorrelationID() gets the correlation identifier of a message.

Getting the Message Identifier

public byte[] getJMSCorrelationIDAsBytes()
          throws JMSException

AQjmsMessage.getJMSMessageID() gets the message identifier of a message as bytes or a string.

Getting JMS Message Properties

This section contains these topics:

Getting a Boolean Message Property

public boolean getBooleanProperty(java.lang.String name)
          throws JMSException

AQjmsMessage.getBooleanProperty() gets a message property as Boolean. It has the following parameter:

Parameter	Description
`name`	Name of the Boolean property

Getting a String Message Property

public java.lang.String getStringProperty(java.lang.String name)
          throws JMSException

AQjmsMessage.getStringProperty() gets a message property as string. It has the following parameter:

Parameter	Description
`name`	Name of the string property

Getting an Integer Message Property

public int getIntProperty(java.lang.String name)
          throws JMSException

AQjmsMessage.getIntProperty() gets a message property as integer. It has the following parameter:

Parameter	Description
`name`	Name of the integer property

Getting a Double Message Property

public double getDoubleProperty(java.lang.String name)
                         throws JMSException

AQjmsMessage.getDoubleProperty() gets a message property as double. It has the following parameter:

Parameter	Description
`name`	Name of the double property

Getting a Float Message Property

public float getFloatProperty(java.lang.String name)
          throws JMSException

AQjmsMessage.getFloatProperty() gets a message property as float. It has the following parameter:

Parameter	Description
`name`	Name of the float property

Getting a Byte Message Property

public byte getByteProperty(java.lang.String name)
          throws JMSException

AQjmsMessage.getByteProperty() gets a message property as byte. It has the following parameter:

Parameter	Description
`name`	Name of the byte property

Getting a Long Message Property

public long getLongProperty(java.lang.String name)
          throws JMSException

AQjmsMessage.getLongProperty() gets a message property as long. It has the following parameter:

Parameter	Description
`name`	Name of the long property

Getting a Short Message Property

public short getShortProperty(java.lang.String name)
                       throws JMSException

AQjmsMessage.getShortProperty() gets a message property as short. It has the following parameter:

Parameter	Description
`name`	Name of the short property

Getting an Object Message Property

public java.lang.Object getObjectProperty(java.lang.String name)
                                   throws JMSException

AQjmsMessage.getObjectProperty() gets a message property as object. It has the following parameter:

Parameter	Description
`name`	Name of the object property

Example 15-12 Getting Message Property as an Object

TextMessage message;
message.getObjectProperty("empid", new Integer(1000);

Closing and Shutting Down

This section contains these topics:

Closing a MessageProducer

public void close()
           throws JMSException

AQjmsProducer.close() closes a MessageProducer.

Closing a Message Consumer

public void close()
           throws JMSException

AQjmsConsumer.close() closes a message consumer.

Stopping a JMS Connection

public void stop()
          throws JMSException

AQjmsConnection.stop() stops a JMS connection.

Closing a JMS Session

public void close()
           throws JMSException

AQjmsSession.close() closes a JMS session.

Closing a JMS Connection

public void close()
          throws JMSException

AQjmsConnection.close() closes a JMS connection and releases all resources allocated on behalf of the connection. Because the JMS provider typically allocates significant resources outside the JVM on behalf of a connection, clients should close them when they are not needed. Relying on garbage collection to eventually reclaim these resources may not be timely enough.

Troubleshooting

This section contains these topics:

Getting a JMS Error Code

public java.lang.String getErrorCode()

AQjmsException.getErrorCode() gets the error code for a JMS exception.

Getting a JMS Error Number

public int getErrorNumber()

AQjmsException.getErrorNumber() gets the error number for a JMS exception.

Note:

This method will be deprecated in a future release. Use getErrorCode() instead.

Getting an Exception Linked to a JMS Exception

public java.lang.String getLinkString()

AQjmsException.getLinkString() gets the exception linked to a JMS exception. In general, this contains the SQL exception raised by the database.

Printing the Stack Trace for a JMS Exception

public void printStackTrace(java.io.PrintStream s)

AQjmsException.printStackTrace() prints the stack trace for a JMS exception.

Setting an Exception Listener

public void setExceptionListener(javax.jms.ExceptionListener listener)
                          throws JMSException

AQjmsConnection.setExceptionListener() specifies an exception listener for a connection. It has the following parameter:

Parameter	Description
`listener`	Exception listener

If an exception listener has been registered, then it is informed of any serious problem detected for a connection. This is accomplished by calling the listener onException() method, passing it a JMS exception describing the problem. This allows a JMS client to be notified of a problem asynchronously. Some connections only consume messages, so they have no other way to learn the connection has failed.

Example 15-13 Specifying Exception Listener for Connection

//register an exception listener
Connection jms_connection;
jms_connection.setExceptionListener(
    new ExceptionListener() {
        public void onException (JMSException jmsException) {
            System.out.println("JMS-EXCEPTION: " + jmsException.toString());
        }
    };
  );

Getting an Exception Listener

public javax.jms.ExceptionListener getExceptionListener()
                                                 throws JMSException

AQjmsConnection.getExceptionListener() gets the exception listener for the connection.

Example 15-14 demonstrates how to use ExceptionListener with MessageListener. Ensure that the following conditions are met:

The user jmsuser with password jmsuser is created in the database, with appropriate privileges.
The queue demoQueue is created and started.

This example demonstrates how to make the MessageListener asynchronously receive the messages, where the exception listener recreates the JMS objects in case there is a connection restart.

Example 15-14 Using ExceptionListener with MessageListener

import java.util.Enumeration;
import java.util.Properties;
 
import javax.jms.Connection;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.QueueBrowser;
import javax.jms.Session;
import javax.jms.TextMessage;
 
import oracle.jms.AQjmsConnectionFactory;
import oracle.jms.AQjmsFactory;
import oracle.jms.AQjmsSession;
 
public class JMSDemo {
 
  static String queueName = "demoQueue";
 
  static String queueOwner = "jmsuser";
 
  static String queueOwnerPassword = "jmsuser";
 
  static Connection connection = null;
 
  static int numberOfMessages = 25000;
 
  static int messageCount = 0;
 
  static String jdbcURL = "";
 
  public static void main(String args[]) {
    try {
      jdbcURL = System.getProperty("JDBC_URL");
 
      if (jdbcURL == null)
        System.out
            .println("The system property JDBC_URL has not been set, " +
            		"usage:java -DJDBC_URL=xxx filename ");
      else {
        JMSDemo demo = new JMSDemo();
        demo.performJmsOperations();
      }
    } catch (Exception exception) {
      System.out.println("Exception : " + exception);
      exception.printStackTrace();
    } finally {
      try {
        if (connection != null)
          connection.close();
      } catch (Exception exc) {
        exc.printStackTrace();
      }
    }
    System.out.println("\nEnd of Demo aqjmsdemo11.");
  }
 
  public void performJmsOperations() {
    try {
      connection = getConnection(jdbcURL);
      Session session = connection.createSession(false,
          Session.AUTO_ACKNOWLEDGE);
      Queue queue = session.createQueue(queueName);
 
      // remove the messages from the Queue
      drainQueue(queueName, queueOwner, jdbcURL, true);
 
      // set the exception listener on the Connection
      connection.setExceptionListener(new DemoExceptionListener());
 
      MessageProducer producer = session.createProducer(queue);
      TextMessage textMessage = null;
 
      System.out.println("Sending " + numberOfMessages + " messages to queue "
          + queueName);
      for (int i = 0; i < numberOfMessages; i++) {
        textMessage = session.createTextMessage();
        textMessage.setText("Sample message text");
        producer.send(textMessage);
      }
 
      MessageConsumer consumer = session.createConsumer(queue);
      System.out.println("Setting the message listener ...");
      consumer.setMessageListener(new DemoMessageListener());
      connection.start();
 
      // Introduce a long wait to allow the listener to receive all the messages
      while (messageCount < numberOfMessages) {
        try {
          Thread.sleep(5000);
        } catch (InterruptedException interruptedException) {
        }
      }
    } catch (JMSException jmsException) {
      jmsException.printStackTrace();
    }
  }
 
  // Sample message listener
  static class DemoMessageListener implements javax.jms.MessageListener {
 
    public void onMessage(Message message) {
      try {
        System.out.println("Message listener received message with JMSMessageID "
                + message.getJMSMessageID());
        messageCount++;
      } catch (JMSException jmsException) {
        System.out.println("JMSException " + jmsException.getMessage());
      }
    }
  }
 
  // sample exception listener
  static class DemoExceptionListener implements javax.jms.ExceptionListener {
 
    public void onException(JMSException jmsException) {      
      try {
        // As a first step close the connection
        if (connection != null)
          connection.close();
      } catch (JMSException exception) {}
 
      try {
        System.out.println("Re-create the necessary JMS objects ...");
        connection = getConnection(jdbcURL);
        connection.start();
        Session session = connection.createSession(false,
            Session.AUTO_ACKNOWLEDGE);
        Queue queue = session.createQueue(queueName);
        MessageConsumer consumer = session.createConsumer(queue);
        consumer.setMessageListener(new DemoMessageListener());
      } catch (JMSException newJmsException) {
        newJmsException.printStackTrace();
      }
    }
  }
 
  // Utility method to get a connection
  static Connection getConnection(String jdbcUrl) throws JMSException {
    Properties prop = new Properties();
    prop.put("user", queueOwner);
    prop.put("password", queueOwnerPassword);
 
    AQjmsConnectionFactory fact = (AQjmsConnectionFactory) AQjmsFactory
        .getConnectionFactory(jdbcUrl, prop);
    Connection conn = fact.createConnection();
    return conn;
  }
 
  // Utility method to remove the messages from the queue
  static void drainQueue(String queueName, String queueOwner, String jdbcUrl,
      boolean debugInfo) {
    Connection connection = null;
    Session session = null;
    long timeout = 10000;
    int count = 0;
    Message message = null;
    try {
      connection = getConnection(jdbcUrl);
      connection.start();
      session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
      Queue queue = ((AQjmsSession) session).getQueue(queueOwner, queueName);
 
      MessageConsumer messageConsumer = session.createConsumer(queue);
      QueueBrowser browser = session.createBrowser(queue);
      Enumeration enumeration = browser.getEnumeration();
 
      if (enumeration.hasMoreElements()) {
        while ((message = messageConsumer.receive(timeout)) != null) {
          if (debugInfo) {
            count++;
          }
        }
      }
      messageConsumer.close();
      if (debugInfo) {
        System.out.println("Removed " + count + " messages from the queue : "
            + queueName);
      }
    } catch (JMSException jmsException) {
      jmsException.printStackTrace();
    } finally {
      try {
        if (session != null)
          session.close();
 
        if (connection != null)
          connection.close();
      } catch (Exception exception) {
 
      }
    }
  }
 
}

Example 15-15 Getting the Exception Listener for the Connection

//Get the exception listener
Connection jms_connection;
ExceptionListener el = jms_connection.getExceptionListener();