/**
* Wait for 'count' messages on controlQueue before continuing. Called by a publisher to make sure
* that subscribers have started before it begins publishing messages.
*
* <p>If controlQueue doesn't exist, the method throws an exception.
*
* @param prefix prefix (publisher or subscriber) to be displayed
* @param controlQueueName name of control queue
* @param count number of messages to receive
*/
public static void receiveSynchronizeMessages(String prefix, String controlQueueName, int count)
throws Exception {
QueueConnectionFactory queueConnectionFactory = null;
QueueConnection queueConnection = null;
QueueSession queueSession = null;
Queue controlQueue = null;
QueueReceiver queueReceiver = null;
try {
queueConnectionFactory = SampleUtilities.getQueueConnectionFactory();
queueConnection = queueConnectionFactory.createQueueConnection();
queueSession = queueConnection.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);
controlQueue = getQueue(controlQueueName, queueSession);
queueConnection.start();
} catch (Exception e) {
System.out.println("Connection problem: " + e.toString());
if (queueConnection != null) {
try {
queueConnection.close();
} catch (JMSException ee) {
}
}
throw e;
}
try {
System.out.println(
prefix
+ "Receiving synchronize messages from "
+ controlQueueName
+ "; count = "
+ count);
queueReceiver = queueSession.createReceiver(controlQueue);
while (count > 0) {
queueReceiver.receive();
count--;
System.out.println(prefix + "Received synchronize message; expect " + count + " more");
}
} catch (JMSException e) {
System.out.println("Exception occurred: " + e.toString());
throw e;
} finally {
if (queueConnection != null) {
try {
queueConnection.close();
} catch (JMSException e) {
}
}
}
}
/**
* Send a message to controlQueue. Called by a subscriber to notify a publisher that it is ready
* to receive messages.
*
* <p>If controlQueue doesn't exist, the method throws an exception.
*
* @param prefix prefix (publisher or subscriber) to be displayed
* @param controlQueueName name of control queue
*/
public static void sendSynchronizeMessage(String prefix, String controlQueueName)
throws Exception {
QueueConnectionFactory queueConnectionFactory = null;
QueueConnection queueConnection = null;
QueueSession queueSession = null;
Queue controlQueue = null;
QueueSender queueSender = null;
TextMessage message = null;
try {
queueConnectionFactory = SampleUtilities.getQueueConnectionFactory();
queueConnection = queueConnectionFactory.createQueueConnection();
queueSession = queueConnection.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);
controlQueue = getQueue(controlQueueName, queueSession);
} catch (Exception e) {
System.out.println("Connection problem: " + e.toString());
if (queueConnection != null) {
try {
queueConnection.close();
} catch (JMSException ee) {
}
}
throw e;
}
try {
queueSender = queueSession.createSender(controlQueue);
message = queueSession.createTextMessage();
message.setText("synchronize");
System.out.println(prefix + "Sending synchronize message to " + controlQueueName);
queueSender.send(message);
} catch (JMSException e) {
System.out.println("Exception occurred: " + e.toString());
throw e;
} finally {
if (queueConnection != null) {
try {
queueConnection.close();
} catch (JMSException e) {
}
}
}
}