There are two programs: subscriber and publisher...
Subscriber is able to put the message onto the topic and the message is sent successfully.
When I check the activemq server on my browser it shows 1 msg enqueued . But when I run the consumer code, it is not receiving the message
Here is the producer code:
import javax.jms.*;
import org.apache.activemq.ActiveMQConnection;
import org.apache.activemq.ActiveMQConnectionFactory;
public class producer {
private static String url = ActiveMQConnection.DEFAULT_BROKER_URL;
public static void main(String[] args) throws JMSException {
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(url);
Connection connection = connectionFactory.createConnection();
connection.start();
// JMS messages are sent and received using a Session. We will
// create here a non-transactional session object. If you want
// to use transactions you should set the first parameter to 'true'
Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
Topic topic = session.createTopic("testt");
MessageProducer producer = session.createProducer(topic);
// We will send a small text message saying 'Hello'
TextMessage message = session.createTextMessage();
message.setText("HELLO JMS WORLD");
// Here we are sending the message!
producer.send(message);
System.out.println("Sent message '" + message.getText() + "'");
connection.close();
}
}
After I run this code the output at the console is:
26 Jan, 2012 2:30:04 PM org.apache.activemq.transport.failover.FailoverTransport doReconnect
INFO: Successfully connected to tcp://localhost:61616
Sent message 'HELLO JMS WORLD'
And here is the consumer code:
import javax.jms.*;
import org.apache.activemq.ActiveMQConnection;
import org.apache.activemq.ActiveMQConnectionFactory;
public class consumer {
// URL of the JMS server
private static String url = ActiveMQConnection.DEFAULT_BROKER_URL;
// Name of the topic from which we will receive messages from = " testt"
public static void main(String[] args) throws JMSException {
// Getting JMS connection from the server
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(url);
Connection connection = connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
Topic topic = session.createTopic("testt");
MessageConsumer consumer = session.createConsumer(topic);
MessageListener listner = new MessageListener() {
public void onMessage(Message message) {
try {
if (message instanceof TextMessage) {
TextMessage textMessage = (TextMessage) message;
System.out.println("Received message"
+ textMessage.getText() + "'");
}
} catch (JMSException e) {
System.out.println("Caught:" + e);
e.printStackTrace();
}
}
};
consumer.setMessageListener(listner);
connection.close();
}
}
After I run this code it doesnt show anything.
Can someone help to me to overcome this problem?
Your issue is that your consumer is running and then shutting down immediately.
Try adding this into your consumer:
consumer.setMessageListener(listner);
try {
System.in.read();
} catch (IOException e) {
e.printStackTrace();
}
connection.close();
This will wait until you hit a key before stopping.
Other things to consider:
Use a finally block for the close
Java naming conventions encourage using uppercase for the first letter of a class
The main problem (besides the app closing down to quickly) is that you are sending to a Topic. Topics don't retain messages so if you run your application that produces and then run the consumer, the consumer won't receive anything because it was not subscribed to the topic at the time the message was sent. If you fix the shutdown issue and then run the consumer in one terminal and then run the producer you should then see the message received by your consumer. If you want message retention then you need to use a Queue which will hold onto the message until someone consumes it.
Your producer class is correct. It runs smoothly.
But, your consumer is incorrect & you have to modify it.
First, add setClientID("any_string_value") after creating connection object;
eg: Connection connection = connectionFactory.createConnection();
// need to setClientID value, any string value you wish
connection.setClientID("12345");
secondly, use createDurableSubscriber() method instead of createConsumer() for transmitting message via topic.
MessageConsumer consumer = session.createDurableSubscriber(topic,"SUB1234");
Here is the modified comsumer class:
package mq.test;
import javax.jms.*;
import org.apache.activemq.ActiveMQConnection;
import org.apache.activemq.ActiveMQConnectionFactory;
public class consumer {
// URL of the JMS server
private static String url = ActiveMQConnection.DEFAULT_BROKER_URL;
// Name of the topic from which we will receive messages from = " testt"
public static void main(String[] args) throws JMSException {
// Getting JMS connection from the server
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(url);
Connection connection = connectionFactory.createConnection();
// need to setClientID value, any string value you wish
connection.setClientID("12345");
try{
connection.start();
}catch(Exception e){
System.err.println("NOT CONNECTED!!!");
}
Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
Topic topic = session.createTopic("test_data");
//need to use createDurableSubscriber() method instead of createConsumer() for topic
// MessageConsumer consumer = session.createConsumer(topic);
MessageConsumer consumer = session.createDurableSubscriber(topic,
"SUB1234");
MessageListener listner = new MessageListener() {
public void onMessage(Message message) {
try {
if (message instanceof TextMessage) {
TextMessage textMessage = (TextMessage) message;
System.out.println("Received message"
+ textMessage.getText() + "'");
}
} catch (JMSException e) {
System.out.println("Caught:" + e);
e.printStackTrace();
}
}
};
consumer.setMessageListener(listner);
//connection.close();
}
}
Now, your code will run successfully.
just some:
work with a queue not a topic. messages in topics will be discarded when no consumer is available, they are NOT persistend.
add connection.start() after setting the message listener. you should start a connection when all consumers/producers are properly set up.
wait some time before before closing the connection again.
the topic will probably be your most important source of failure.
Related
I'm am using Virtual Destinations to implement Publish Subscribe model in ActiveMQ 5.15.13.
I have a virtual topic VirtualTopic and there are two queues bound to it. Each queue has its own redelivery policy. Let's say Queue 1 will retry message 2 times in case there is an exception while processing the message and Queue 2 will retry message 3 times. Post retry message will be sent to deadletter queue. I'm also using Individual Dead letter Queue strategy so that each queue has it's own deadletter queue.
I've observed that when a message is sent to VirtualTopic, the message with same message id is delivered to both the queues. I'm facing an issue where if the consumers of both queues are not able to process the message successfully. The message destined for Queue 1 is moved to deadletter queue after retrying for 2 times. But there is no deadletter queue for Queue 2, though message in Queue 2 is retried for 3 times.
Is it the expected behavior?
Code:
public class ActiveMQRedelivery {
private final ActiveMQConnectionFactory factory;
public ActiveMQRedelivery(String brokerUrl) {
factory = new ActiveMQConnectionFactory(brokerUrl);
factory.setUserName("admin");
factory.setPassword("password");
factory.setAlwaysSyncSend(false);
}
public void publish(String topicAddress, String message) {
final String topicName = "VirtualTopic." + topicAddress;
try {
final Connection producerConnection = factory.createConnection();
producerConnection.start();
final Session producerSession = producerConnection.createSession(false, AUTO_ACKNOWLEDGE);
final MessageProducer producer = producerSession.createProducer(null);
final TextMessage textMessage = producerSession.createTextMessage(message);
final Topic topic = producerSession.createTopic(topicName);
producer.send(topic, textMessage, PERSISTENT, DEFAULT_PRIORITY, DEFAULT_TIME_TO_LIVE);
} catch (JMSException e) {
throw new RuntimeException("Message could not be published", e);
}
}
public void initializeConsumer(String queueName, String topicAddress, int numOfRetry) throws JMSException {
factory.getRedeliveryPolicyMap().put(new ActiveMQQueue("*." + queueName + ".>"),
getRedeliveryPolicy(numOfRetry));
Connection connection = factory.createConnection();
connection.start();
final Session consumerSession = connection.createSession(false, CLIENT_ACKNOWLEDGE);
final Queue queue = consumerSession.createQueue("Consumer." + queueName +
".VirtualTopic." + topicAddress);
final MessageConsumer consumer = consumerSession.createConsumer(queue);
consumer.setMessageListener(message -> {
try {
System.out.println("in listener --- " + ((ActiveMQDestination)message.getJMSDestination()).getPhysicalName());
consumerSession.recover();
} catch (JMSException e) {
e.printStackTrace();
}
});
}
private RedeliveryPolicy getRedeliveryPolicy(int numOfRetry) {
final RedeliveryPolicy redeliveryPolicy = new RedeliveryPolicy();
redeliveryPolicy.setInitialRedeliveryDelay(0);
redeliveryPolicy.setMaximumRedeliveries(numOfRetry);
redeliveryPolicy.setMaximumRedeliveryDelay(-1);
redeliveryPolicy.setRedeliveryDelay(0);
return redeliveryPolicy;
}
}
Test:
public class ActiveMQRedeliveryTest {
private static final String brokerUrl = "tcp://0.0.0.0:61616";
private ActiveMQRedelivery activeMQRedelivery;
#Before
public void setUp() throws Exception {
activeMQRedelivery = new ActiveMQRedelivery(brokerUrl);
}
#Test
public void testMessageRedeliveries() throws Exception {
String topicAddress = "testTopic";
activeMQRedelivery.initializeConsumer("queue1", topicAddress, 2);
activeMQRedelivery.initializeConsumer("queue2", topicAddress, 3);
activeMQRedelivery.publish(topicAddress, "TestMessage");
Thread.sleep(3000);
}
#After
public void tearDown() throws Exception {
}
}
I recently came across this problem. To fix this there are 2 attributes that needs to be added to individualDeadLetterStrategy as below
<deadLetterStrategy>
<individualDeadLetterStrategy destinationPerDurableSubscriber="true" enableAudit="false" queuePrefix="DLQ." useQueueForQueueMessages="true"/>
</deadLetterStrategy>
Explanation of attributes:
destinationPerDurableSubscriber - To enable a separate destination per durable subscriber.
enableAudit - The dead letter strategy has a message audit that is enabled by default. This prevents duplicate messages from being added to the configured DLQ. When the attribute is enabled, the same message that isn't delivered for multiple subscribers to a topic will only be placed on one of the subscriber DLQs when the destinationPerDurableSubscriber attribute is set to true i.e. say two consumers fail to acknowledge the same message for the topic, that message will only be placed on the DLQ for one consumer and not the other.
I want to load the JMS messages in a queue in real time, if is a consumer.setMessageListener(myListener) viable and how it works?
I'm not sure how a listener working. I wrote a listener like below.
public class JmsMessageListenerExample {
public static void main(String[] args) throws URISyntaxException, Exception {
BrokerService broker = BrokerFactory.createBroker(new URI(
"broker:(tcp://localhost:61616)"));
broker.start();
Connection connection = null;
try {
// Producer
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(
"tcp://localhost:61616");
connection = connectionFactory.createConnection();
Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
Queue queue = session.createQueue("customerQueue");
String payload = "Important Task";
Message msg = session.createTextMessage(payload);
MessageProducer producer = session.createProducer(queue);
System.out.println("Sending text '" + payload + "'");
producer.send(msg);
// Consumer
MessageConsumer consumer = session.createConsumer(queue);
consumer.setMessageListener(new ConsumerMessageListener("Consumer"));
connection.start();
} finally {
if (connection != null) {
connection.close();
}
broker.stop();
}
}
After I run the JmsMessageListenerExample, it completed quickly and I didn't received any messages. If a listener should keep on running until I stop it?
When you set a JMS message listener it will receive messages asynchronously in its own thread (invoked by the JMS implementation). In your case you need to prevent main from exiting and stopping your application because when that happens the MessageListener will be terminated.
Also, when you say "load the JMS messages in a queue in real time" I assume you mean "consume JMS messages from a queue as soon as possible when queue receives them." If that's the case then a JMS message listener is the right approach.
I have ActiveMQ running on the localhost using the default port, 61616. I put some messages in a Topic called topic.STUDENTS. I have a client program that I am trying to use to read the messages in the Topic. Here is the main part of the program that does not work as expected. I was expecting to get some of the message back but instead I just receive null.
public void receiveMessages() throws URISyntaxException, JMSException, Exception {
try {
//Create a ConnectionFactory
ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://localhost:61616");
//Create a Connection
Connection connection = connectionFactory.createConnection();
connection.start();
//Create a session
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
//Create the destination (Topic or Queue)
Destination destination = session.createTopic("topic.STUDENTS");
//Create a MessageConsumer from the Session to the Topic or Queue
MessageConsumer consumer = session.createConsumer(destination);
//Wait for a message
Message message = consumer.receive(1000);
if (message instanceof TextMessage) {
TextMessage textMessage = (TextMessage) message;
String text = textMessage.getText();
System.out.println("Received: " + text);
} else {
System.out.println("Received: " + message);
}
consumer.close();
session.close();
connection.close();
} catch(Exception e) {
System.out.println("Caught: " + e);
e.printStackTrace();
}
}
This code basically apes the code from ActiveMQ 'Hello World' example: http://activemq.apache.org/hello-world.html
Does anyone know why I do not receive any messages from the Topic? Here is one message that is in the Topic that I can see through the ./activemq browse topic.STUDENTS command:
JMS_BODY_FIELD:JMSText = Invention-my-dear-friends-is-93%-perspiration-6%-electricity
JMS_HEADER_FIELD:JMSExpiration = 0
JMS_HEADER_FIELD:JMSMessageID = ID:user-thinkpad-335i-59919-1457977678059-1:1:1:1:3
JMS_HEADER_FIELD:JMSPriority = 4
JMS_HEADER_FIELD:JMSDestination = topic.STUDENTS
JMS_HEADER_FIELD:JMSTimestamp = 1457977678409
JMS_HEADER_FIELD:JMSRedelivered = false
JMS_HEADER_FIELD:JMSDeliveryMode = persistent
Topics do not retain messages by default, so if you start the consumer after you've produced the messages then any message that was sent before the consumer arrived is gone. If you want to consume messages that were produced while your consumer was offline then you need to use a Queue or register a durable Topic subscriber on the Topic prior to producing the messages.
How do I configure my J2EE application so that I can invoke ActiveMQ service along with tomcat server? I am aware about embedded broker, here asking how to start the ActiveMQ whenever I start tomcat
Current Code (works fine) :
Now I want to remove main() method and use the code to run when tomcat runs.
public class JMSService {
public void produceJMS() throws NamingException, JMSException {
ConnectionFactory connFactory = new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_BROKER_URL);
Connection conn = connFactory.createConnection();
conn.start();
Session session = conn.createSession(false,Session.AUTO_ACKNOWLEDGE);
Destination destination = session.createQueue("testQueue");
MessageProducer producer = session.createProducer(destination);
producer.setDeliveryMode(DeliveryMode.PERSISTENT);
TextMessage message = session.createTextMessage("Test Message ");
// send the message
producer.send(message);
System.out.println("sent: " + message);
}}
Here is my consumer :
public class JMSReceiver implements MessageListener,ExceptionListener {
public static void main(String args[]) throws Exception {
JMSReceiver re = new JMSReceiver();
re.receiveJMS();
}
public void receiveJMS() throws NamingException, JMSException {
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_BROKER_URL);
Connection connection = connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);
// Getting the queue 'testQueue'
Destination destination = session.createQueue("testQueue");
MessageConsumer consumer = session.createConsumer(destination);
// set an asynchronous message listener
JMSReceiver asyncReceiver = new JMSReceiver();
consumer.setMessageListener(asyncReceiver);
connection.setExceptionListener(asyncReceiver);
}
#Override
public void onMessage(Message message) {
System.out.println("Received message : " +message);
}
}
What #Tim Bish said is correct. You either need to have a timer say for example receiver should listen for 1 hour- or make it available until program terminate. Either case you need to start your consumer program once:
Change your receiveJMS method as follows:
public void receiveJMS() throws NamingException, JMSException {
try{
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_BROKER_URL);
Connection connection = connectionFactory.createConnection();
connection.start(); // it's the start point
Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);
// Getting the queue 'testQueue'
Destination destination = session.createQueue("testQueue");
MessageConsumer consumer = session.createConsumer(destination);
// set an asynchronous message listener
// JMSReceiver asyncReceiver = new JMSReceiver();
//no need to create another object
consumer.setMessageListener(this);
connection.setExceptionListener(this);
// connection.close(); once this is closed consumer no longer active
Thread.sleep(60 *60 * 1000); // receive messages for 1 hour
}finally{
connection.close();// after 1 hour close it
}
}
The above program will listen upto 1 hour. If you want it as long as the program run, remove the finally block. But the recommended way is to close it somehow. since your application seems to be standalone ,you can check the java runtime shutdown hook, where you can specify how to release such resources while program terminates.
If your consumer is a web application you can close it in a ServletContextlistner.
You aren't giving the consumer application any time to actually receive a message, you create it, then you close it. You either need to use a timed receive call to do an sync receive of the message from the Queue or you need to add some sort of wait in the main method such as a CountDownLatch etc to allow the async onMessage call to trigger shutdown once processing of the message is complete.
I've been working with JMS and ActiveMQ. Everything is working wonders. I am not using spring, nor can I.
The interface javax.jms.MessageListener has only one method, onMessage. From within a implementation, there is a chance an exception will be thrown. If in fact an exception gets thrown, then I say the message wasn't properly processed and needs to be re-tried. So, I need ActiveMQ to wait for a little while and then, retry. i.e. I need the thrown exception to rollback the JMS transaction.
How can I accomplish such a behaviour?
Maybe there is some configuration in ActiveMQ I wasn't able to find.
Or... maybe could do away with registering MessageListeners to consumers and consume the messages myself, in a a loop like:
while (true) {
// ... some administrative stuff like ...
session = connection.createSesstion(true, SESSION_TRANSACTED)
try {
Message m = receiver.receive(queue, 1000L);
theMessageListener.onMessage(m);
session.commit();
} catch (Exception e) {
session.rollback();
Thread.sleep(someTimeDefinedSomewhereElse);
}
// ... some more administrative stuff
}
in a couple of threads, instead of registering the listener.
Or... I could somehow decorate/AOP/byte-manipulate the MessageListeners to do this themselves.
What route would you take and why?
note: I don't have full control over the MessageListeners code.
EDIT
A test for proof of concept:
#Test
#Ignore("Interactive test, just a proof of concept")
public void transaccionConListener() throws Exception {
final AtomicInteger atomicInteger = new AtomicInteger(0);
BrokerService brokerService = new BrokerService();
String bindAddress = "vm://localhost";
brokerService.addConnector(bindAddress);
brokerService.setPersistenceAdapter(new MemoryPersistenceAdapter());
brokerService.setUseJmx(false);
brokerService.start();
ActiveMQConnectionFactory activeMQConnectionFactory = new ActiveMQConnectionFactory(bindAddress);
RedeliveryPolicy redeliveryPolicy = new RedeliveryPolicy();
redeliveryPolicy.setInitialRedeliveryDelay(500);
redeliveryPolicy.setBackOffMultiplier(2);
redeliveryPolicy.setUseExponentialBackOff(true);
redeliveryPolicy.setMaximumRedeliveries(2);
activeMQConnectionFactory.setRedeliveryPolicy(redeliveryPolicy);
activeMQConnectionFactory.setUseRetroactiveConsumer(true);
activeMQConnectionFactory.setClientIDPrefix("ID");
PooledConnectionFactory pooledConnectionFactory = new PooledConnectionFactory(activeMQConnectionFactory);
pooledConnectionFactory.start();
Connection connection = pooledConnectionFactory.createConnection();
Session session = connection.createSession(false, Session.DUPS_OK_ACKNOWLEDGE);
Queue helloQueue = session.createQueue("Hello");
MessageConsumer consumer = session.createConsumer(helloQueue);
consumer.setMessageListener(new MessageListener() {
#Override
public void onMessage(Message message) {
TextMessage textMessage = (TextMessage) message;
try {
switch (atomicInteger.getAndIncrement()) {
case 0:
System.out.println("OK, first message received " + textMessage.getText());
message.acknowledge();
break;
case 1:
System.out.println("NOPE, second must be retried " + textMessage.getText());
throw new RuntimeException("I failed, aaaaah");
case 2:
System.out.println("OK, second message received " + textMessage.getText());
message.acknowledge();
}
} catch (JMSException e) {
e.printStackTrace(System.out);
}
}
});
connection.start();
{
// A client sends two messages...
Connection connection1 = pooledConnectionFactory.createConnection();
Session session1 = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
connection1.start();
MessageProducer producer = session1.createProducer(helloQueue);
producer.send(session1.createTextMessage("Hello World 1"));
producer.send(session1.createTextMessage("Hello World 2"));
producer.close();
session1.close();
connection1.stop();
connection1.close();
}
JOptionPane.showInputDialog("I will wait, you watch the log...");
consumer.close();
session.close();
connection.stop();
connection.close();
pooledConnectionFactory.stop();
brokerService.stop();
assertEquals(3, atomicInteger.get());
}
If you want to use SESSION_TRANSACTED as your acknowledgement mode, then you need to setup a RedeliveryPolicy on your Connection/ConnectionFactory. This page on ActiveMQ's website also contains some good info for what you might need to do.
Since you aren't using Spring, you can setup a RedeliveryPolicy with something similar to the following code (taken from one of the above links):
RedeliveryPolicy policy = connection.getRedeliveryPolicy();
policy.setInitialRedeliveryDelay(500);
policy.setBackOffMultiplier(2);
policy.setUseExponentialBackOff(true);
policy.setMaximumRedeliveries(2);
Edit
Taking your code snippet added to the answer, the following shows how this works with transactions. Try this code with the Session.rollback() method commented out and you'll see that using SESION_TRANSACTED and Session.commit/rollback works as expected:
#Test
public void test() throws Exception {
final AtomicInteger atomicInteger = new AtomicInteger(0);
BrokerService brokerService = new BrokerService();
String bindAddress = "vm://localhost";
brokerService.addConnector(bindAddress);
brokerService.setPersistenceAdapter(new MemoryPersistenceAdapter());
brokerService.setUseJmx(false);
brokerService.start();
ActiveMQConnectionFactory activeMQConnectionFactory = new ActiveMQConnectionFactory(bindAddress);
RedeliveryPolicy redeliveryPolicy = new RedeliveryPolicy();
redeliveryPolicy.setInitialRedeliveryDelay(500);
redeliveryPolicy.setBackOffMultiplier(2);
redeliveryPolicy.setUseExponentialBackOff(true);
redeliveryPolicy.setMaximumRedeliveries(2);
activeMQConnectionFactory.setRedeliveryPolicy(redeliveryPolicy);
activeMQConnectionFactory.setUseRetroactiveConsumer(true);
activeMQConnectionFactory.setClientIDPrefix("ID");
PooledConnectionFactory pooledConnectionFactory = new PooledConnectionFactory(activeMQConnectionFactory);
pooledConnectionFactory.start();
Connection connection = pooledConnectionFactory.createConnection();
final Session session = connection.createSession(true, Session.SESSION_TRANSACTED);
Queue helloQueue = session.createQueue("Hello");
MessageConsumer consumer = session.createConsumer(helloQueue);
consumer.setMessageListener(new MessageListener() {
public void onMessage(Message message) {
TextMessage textMessage = (TextMessage) message;
try {
switch (atomicInteger.getAndIncrement()) {
case 0:
System.out.println("OK, first message received " + textMessage.getText());
session.commit();
break;
case 1:
System.out.println("NOPE, second must be retried " + textMessage.getText());
session.rollback();
throw new RuntimeException("I failed, aaaaah");
case 2:
System.out.println("OK, second message received " + textMessage.getText());
session.commit();
}
} catch (JMSException e) {
e.printStackTrace(System.out);
}
}
});
connection.start();
{
// A client sends two messages...
Connection connection1 = pooledConnectionFactory.createConnection();
Session session1 = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
connection1.start();
MessageProducer producer = session1.createProducer(helloQueue);
producer.send(session1.createTextMessage("Hello World 1"));
producer.send(session1.createTextMessage("Hello World 2"));
producer.close();
session1.close();
connection1.stop();
connection1.close();
}
JOptionPane.showInputDialog("I will wait, you watch the log...");
consumer.close();
session.close();
connection.stop();
connection.close();
pooledConnectionFactory.stop();
assertEquals(3, atomicInteger.get());
}
}
You need to set the acknowledgment mode to Session.CLIENT_ACKNOWLEDGE, the client acknowledges a consumed message by calling the message's acknowledge method.
QueueSession session = connection.createQueueSession(false, Session.CLIENT_ACKNOWLEDGE);
Then, after processing the message to need to call the Message.acknowledge() method in order to remove that message.
Message message = ...;
// Processing message
message.acknowledge();
A little late, but here goes -
I would not use a MessageListener but rather a global pools to manage listening and processing.
ListeningPool -> listener -> submit processing task -> ProcessingPool -> execute and acknowledge or close without acknowledgment.
Maintain 2 thread pools, one for listeners and one for processors.
Have a listening Runnable implementation that listens to a queue in a while true loop, and consumer.receive(timeout) method. In the finally block, close connection, session and consumer if there was no message received. If a message is received, submit a task to processing pool with all the conn, session, message and consumer arguments.
Have a processing implementation that takes in the message, connection, session and consumer. Do your processing and acknowledge if all ok. If not, close without acknowledgement. This would trigger a redelivery according to your server's redelivery policy.
Initialize your listening pool with all the Listener Tasks, listening for messages, each for one queue. Initialize your processing pool with parameters acceptable to your application runtime.
public class CustomMessageListener implements Runnable {
private ConnectionFactory connectionFactory;
private MessageProcessor processor;
private long backOff;
private boolean stopped = false;
private Executor processPool;
public CustomMessageListener(ConnectionFactory connectionFactory,
long backOff, MessageProcessor processor, Executor processPool) {
this.connectionFactory = connectionFactory;
this.backOff = backOff;
this.processor = processor;
this.processPool = processPool;
}
#Override
public void run() {
while (!stopped) {
listen();
}
}
public void stop() {
this.stopped = true;
}
public void listen() {
Connection c = null;
Session s = null;
MessageConsumer consumer = null;
boolean received = false;
try {
c = connectionFactory.createConnection();
s = c.createSession(false, Session.CLIENT_ACKNOWLEDGE);
consumer = s.createConsumer(...);
Message message = consumer.receive(backOff); // waits maximum backOff ms for a message
if (message != null) {
received = true;
// submit a task to processing pool...
executor.submit(processor.process(message, s, consumer, c));
}
} catch (JMSException ex) {
// log your exception
} finally {
if (!received) {
// close conn, session, consumer
}
}
}
}
public class MessageProcessor {
public Runnable process(Message msg, Session s, MessageConsumer consumer, Connection conn) {
return () - > {
try {
//do your processing
msg.acknowledge(); // done
} catch (JMSException ex) {
// log your exception
} finally {
// close your resources
}
};
}
}
You can call stop() to stop listening for more messages, for a graceful shutdown. Include a queueName in the constructor to listen for a particular queue.
If your session is transacted,then "acknowledgeMode" is ignored anyways..So, just leave your session transacted and use session.rollback and session.commit to commit or rollback your transaction.