I am using IBM MQ Classes for JMS (IBM MQ Version 8.0.0.4) with auto-reconnection configured. According to the docs, reconnection happens implicitly. I would like to issue a simple log statement in the event of reconnection. For that reason, I need to somehow get informed, when that happens.
In the IBM docs on page Application Recovery I stumbled over section "Detecting failover" where it says:
Reconnection aware: Register an MQCBT_EVENT_HANDLER event handler with the queue manager. The event handler is posted with MQRC_RECONNECTING when the client starts to try to reconnect to the server, and MQRC_RECONNECTED after a successful reconnection. You can then run a routine to reestablish a predictable state so that the client application is able to continue processing.
Unfortunately, I did not find a code example for Java/JMS that demonstrates how and where to register such an event handler. I don't know if that is even supported in my case. Could anyone provide me to the right direction or even provide a code sample? Thank you very much.
Question Update from February 5, 2020:
Added the following code example created by myself, after having received Sashi's initial answer from January 27, 2020.
public static void main(String[] args) {
Connection connection = null;
Session session = null;
Object destination = null;
MessageProducer producer = null;
try {
JmsFactoryFactory jmsFactoryFactory = JmsFactoryFactory.getInstance(WMQConstants.WMQ_PROVIDER);
JmsConnectionFactory cf = jmsFactoryFactory.createConnectionFactory();
cf.setStringProperty(WMQConstants.WMQ_HOST_NAME, HOST);
cf.setIntProperty(WMQConstants.WMQ_PORT, PORT);
cf.setStringProperty(WMQConstants.WMQ_CHANNEL, CHANNEL);
cf.setIntProperty(WMQConstants.WMQ_CONNECTION_MODE, WMQConstants.WMQ_CM_CLIENT);
cf.setStringProperty(WMQConstants.WMQ_QUEUE_MANAGER, QM_NAME);
cf.setIntProperty(WMQConstants.WMQ_CLIENT_RECONNECT_OPTIONS, WMQConstants.WMQ_CLIENT_RECONNECT);
cf.setIntProperty(WMQConstants.WMQ_CLIENT_RECONNECT_TIMEOUT, RECONNECT_TIMEOUT);
connection = cf.createConnection();
connection.setExceptionListener(new MQExceptionListener());
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
destination = session.createQueue(QUEUE);
producer = session.createProducer((Destination)destination);
connection.start();
} catch (JMSException ex) {
LOGGER.error(ex.toString());
}
}
public class MQExceptionListener implements ExceptionListener {
public void onException(JMSException e) {
System.out.println(e);
if(e.getLinkedException() != null)
System.out.println(e.getLinkedException());
}
}
This is what I get in the logs:
ERROR [Main.main:57] (main) com.ibm.msg.client.jms.DetailedIllegalStateException: JMSWMQ0018: Failed to connect to queue manager '<hostname>' with connection mode 'Client' and host name '<hostname>(<port>)'.
Check the queue manager is started and if running in client mode, check there is a listener running. Please see the linked exception for more information.
ERROR [Main.main:61] (main) Inner exceptions:
ERROR [Main.main:65] (main) com.ibm.mq.MQException: JMSCMQ0001: IBM MQ call failed with compcode '2' ('MQCC_FAILED') reason '2538' ('MQRC_HOST_NOT_AVAILABLE').
ERROR [Main.main:65] (main) com.ibm.mq.jmqi.JmqiException: CC=2;RC=2538;AMQ9204: Connection to host '<hostname>(<port>)' rejected. [1=com.ibm.mq.jmqi.JmqiException[CC=2;RC=2538;AMQ9204: Connection to host '<hostname>/<ip>:<port>' rejected. [1=java.net.ConnectException[Connection refused: connect],3=<hostname>/<ip>:<port>,4=TCP,5=Socket.connect]],3=<hostname>(<port>),5=RemoteTCPConnection.bindAndConnectSocket]
ERROR [Main.main:65] (main) com.ibm.mq.jmqi.JmqiException: CC=2;RC=2538;AMQ9204: Connection to host '<hostname>/<ip>:<port>' rejected. [1=java.net.ConnectException[Connection refused: connect],3=<hostname>/<ip>:<port>,4=TCP,5=Socket.connect]
ERROR [Main.main:65] (main) java.net.ConnectException: Connection refused: connect
Question Update from February 11, 2020:
I've added this additions based on feedback received by Sashi on February 5, 2020.
I have tried to build a minimal application that connects to an IBM MQ instance. Here's the code:
Application.java
public class Application {
private static final Logger LOGGER = LoggerFactory.getLogger(Application.class);
public static void main(String[] args) {
new Application().run();
}
private void run() {
MQWriter writer = new MQWriter();
int i = 1;
while (true) {
String message = "Hello Testing " + i;
LOGGER.info("Sending message {} to MQ server...", message);
writer.write(message);
i++;
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
MQConnectionDetails.java
public class MQConnectionDetails {
public static final String HOST = "XXX.XXX.XXX.XXX";
public static final int PORT = 1414;
public static final String QM_NAME = "QM1";
public static final String CHANNEL = "DEV.APP.SVRCONN";
public static final String QUEUE = "DEV.QUEUE.1";
public static final int RECONNECT_TIMEOUT = 60; // 1 minute
}
MQWriter.java
public class MQWriter {
private static final Logger LOGGER = LoggerFactory.getLogger(MQWriter.class);
private Connection connection = null;
private Session session = null;
private Object destination = null;
private MessageProducer producer = null;
public MQWriter() {
try {
JmsFactoryFactory jff = JmsFactoryFactory.getInstance(WMQConstants.WMQ_PROVIDER);
JmsConnectionFactory jcf = jff.createConnectionFactory();
jcf.setStringProperty(WMQConstants.WMQ_HOST_NAME, MQConnectionDetails.HOST);
jcf.setIntProperty(WMQConstants.WMQ_PORT, MQConnectionDetails.PORT);
jcf.setStringProperty(WMQConstants.WMQ_CHANNEL, MQConnectionDetails.CHANNEL);
jcf.setIntProperty(WMQConstants.WMQ_CONNECTION_MODE, WMQConstants.WMQ_CM_CLIENT);
jcf.setStringProperty(WMQConstants.WMQ_QUEUE_MANAGER, MQConnectionDetails.QM_NAME);
jcf.setIntProperty(WMQConstants.WMQ_CLIENT_RECONNECT_OPTIONS, WMQConstants.WMQ_CLIENT_RECONNECT);
jcf.setIntProperty(WMQConstants.WMQ_CLIENT_RECONNECT_TIMEOUT, MQConnectionDetails.RECONNECT_TIMEOUT);
LOGGER.info("Initializing connection to write queue {} on {}:{}...",
MQConnectionDetails.QUEUE,
MQConnectionDetails.HOST,
MQConnectionDetails.PORT);
connection = jcf.createConnection();
connection.setExceptionListener(new MQExceptionListener());
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
destination = session.createQueue(MQConnectionDetails.QUEUE);
producer = session.createProducer((Destination)destination);
connection.start();
} catch (JMSException ex) {
LOGGER.error("Error initializing connection to write queue", ex);
}
}
public void write(String message) {
try {
TextMessage textMessage = session.createTextMessage(message);
producer.send(textMessage);
} catch (Exception ex) {
LOGGER.error("Error sending message to write queue", ex);
}
}
}
MQExceptionListener.java
public class MQExceptionListener implements ExceptionListener {
private static final Logger LOGGER = LoggerFactory.getLogger(MQExceptionListener.class);
public void onException(JMSException ex) {
LOGGER.error("=====");
LOGGER.error(ex.toString());
if (ex.getLinkedException() != null) {
LOGGER.error(ex.getLinkedException().toString());
}
LOGGER.error("=====");
}
}
The test scenario I ran is like this:
This is what I've observed:
Here is a summary of the exceptions that got thrown:
Exceptions on console:
2020-02-11 09:50:16,155 INFO [Application.run:21] (main) Sending message Hello Testing 13 to MQ server...
2020-02-11 09:50:17,285 INFO [Application.run:21] (main) Sending message Hello Testing 14 to MQ server...
2020-02-11 09:50:18,413 INFO [Application.run:21] (main) Sending message Hello Testing 15 to MQ server...
2020-02-11 09:50:19,555 INFO [Application.run:21] (main) Sending message Hello Testing 16 to MQ server...
2020-02-11 09:51:45,966 ERROR [MQExceptionListener.onException:14] (JMSCCThreadPoolWorker-6) =====
2020-02-11 09:51:45,966 ERROR [MQExceptionListener.onException:15] (JMSCCThreadPoolWorker-6) com.ibm.msg.client.jms.DetailedJMSException: JMSWMQ1107: A problem with this connection has occurred.
An error has occurred with the IBM MQ JMS connection.
Use the linked exception to determine the cause of this error.
2020-02-11 09:51:45,966 ERROR [MQExceptionListener.onException:17] (JMSCCThreadPoolWorker-6) com.ibm.mq.MQException: MQ delivered an asynchronous event with completion code '2', and reason '2009'.
2020-02-11 09:51:45,966 ERROR [MQExceptionListener.onException:19] (JMSCCThreadPoolWorker-6) =====
2020-02-11 09:51:45,967 ERROR [MQWriter.write:52] (main) Error sending message to write queue
com.ibm.msg.client.jms.DetailedJMSException: JMSWMQ2007: Failed to send a message to destination 'DEV.QUEUE.1'.
JMS attempted to perform an MQPUT or MQPUT1; however IBM MQ reported an error.
Use the linked exception to determine the cause of this error.
at com.ibm.msg.client.wmq.common.internal.Reason.reasonToException(Reason.java:595)
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:215)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.checkJmqiCallSuccess(WMQMessageProducer.java:1288)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.checkJmqiCallSuccess(WMQMessageProducer.java:1245)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.access$800(WMQMessageProducer.java:76)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer$SpiIdentifiedProducerShadow.sendInternal(WMQMessageProducer.java:906)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer$ProducerShadow.send(WMQMessageProducer.java:566)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.send(WMQMessageProducer.java:1428)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.sendMessage(JmsMessageProducerImpl.java:855)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.synchronousSendInternal(JmsMessageProducerImpl.java:2055)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.sendInternal(JmsMessageProducerImpl.java:1993)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.send(JmsMessageProducerImpl.java:1486)
at com.ibm.mq.jms.MQMessageProducer.send(MQMessageProducer.java:293)
at org.example.MQWriter.write(MQWriter.java:50)
at org.example.Application.run(Application.java:22)
at org.example.Application.main(Application.java:13)
Caused by: com.ibm.mq.MQException: JMSCMQ0001: IBM MQ call failed with compcode '2' ('MQCC_FAILED') reason '2009' ('MQRC_CONNECTION_BROKEN').
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:203)
... 14 more
Caused by: com.ibm.mq.jmqi.JmqiException: CC=2;RC=2009
at com.ibm.mq.jmqi.remote.api.RemoteHconn$ReconnectionState.recordFailure(RemoteHconn.java:4931)
at com.ibm.mq.jmqi.remote.api.RemoteHconn.setReconnectionFailureInner(RemoteHconn.java:2650)
at com.ibm.mq.jmqi.remote.api.RemoteParentHconn.setReconnectionFailure(RemoteParentHconn.java:152)
at com.ibm.mq.jmqi.remote.impl.RemoteReconnectThread.bestHconn(RemoteReconnectThread.java:265)
at com.ibm.mq.jmqi.remote.impl.RemoteReconnectThread.run(RemoteReconnectThread.java:115)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueItem.runTask(WorkQueueItem.java:319)
at com.ibm.msg.client.commonservices.workqueue.SimpleWorkQueueItem.runItem(SimpleWorkQueueItem.java:99)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueItem.run(WorkQueueItem.java:343)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueManager.runWorkQueueItem(WorkQueueManager.java:312)
at com.ibm.msg.client.commonservices.j2se.workqueue.WorkQueueManagerImplementation$ThreadPoolWorker.run(WorkQueueManagerImplementation.java:1227)
2020-02-11 09:51:46,969 INFO [Application.run:21] (main) Sending message Hello Testing 17 to MQ server...
2020-02-11 09:51:46,972 ERROR [MQWriter.write:52] (main) Error sending message to write queue
com.ibm.msg.client.jms.DetailedJMSException: JMSWMQ2007: Failed to send a message to destination 'DEV.QUEUE.1'.
JMS attempted to perform an MQPUT or MQPUT1; however IBM MQ reported an error.
Use the linked exception to determine the cause of this error.
at com.ibm.msg.client.wmq.common.internal.Reason.reasonToException(Reason.java:595)
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:215)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.checkJmqiCallSuccess(WMQMessageProducer.java:1288)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.checkJmqiCallSuccess(WMQMessageProducer.java:1245)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.access$800(WMQMessageProducer.java:76)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer$SpiIdentifiedProducerShadow.sendInternal(WMQMessageProducer.java:906)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer$ProducerShadow.send(WMQMessageProducer.java:566)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.send(WMQMessageProducer.java:1428)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.sendMessage(JmsMessageProducerImpl.java:855)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.synchronousSendInternal(JmsMessageProducerImpl.java:2055)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.sendInternal(JmsMessageProducerImpl.java:1993)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.send(JmsMessageProducerImpl.java:1486)
at com.ibm.mq.jms.MQMessageProducer.send(MQMessageProducer.java:293)
at org.example.MQWriter.write(MQWriter.java:50)
at org.example.Application.run(Application.java:22)
at org.example.Application.main(Application.java:13)
Caused by: com.ibm.mq.MQException: JMSCMQ0001: IBM MQ call failed with compcode '2' ('MQCC_FAILED') reason '2009' ('MQRC_CONNECTION_BROKEN').
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:203)
... 14 more
Caused by: com.ibm.mq.jmqi.JmqiException: CC=2;RC=2009
at com.ibm.mq.jmqi.remote.api.RemoteHconn$ReconnectionState.recordFailure(RemoteHconn.java:4931)
at com.ibm.mq.jmqi.remote.api.RemoteHconn.setReconnectionFailureInner(RemoteHconn.java:2650)
at com.ibm.mq.jmqi.remote.api.RemoteParentHconn.setReconnectionFailure(RemoteParentHconn.java:152)
at com.ibm.mq.jmqi.remote.impl.RemoteReconnectThread.bestHconn(RemoteReconnectThread.java:265)
at com.ibm.mq.jmqi.remote.impl.RemoteReconnectThread.run(RemoteReconnectThread.java:115)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueItem.runTask(WorkQueueItem.java:319)
at com.ibm.msg.client.commonservices.workqueue.SimpleWorkQueueItem.runItem(SimpleWorkQueueItem.java:99)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueItem.run(WorkQueueItem.java:343)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueManager.runWorkQueueItem(WorkQueueManager.java:312)
at com.ibm.msg.client.commonservices.j2se.workqueue.WorkQueueManagerImplementation$ThreadPoolWorker.run(WorkQueueManagerImplementation.java:1227)
Question Update from February 12, 2020
Added this sample and findings based on JoshMc's answer from February 11, 2020. My comments on this sample:
MQWriter2.java
public class MQWriter2 {
private static final Logger LOGGER = LoggerFactory.getLogger(MQWriter2.class);
private Connection connection = null;
private Session session = null;
private Queue destination = null;
private MessageProducer producer = null;
public MQWriter2() {
try {
MQConnectionFactory factory = new MQConnectionFactory();
factory.setTransportType(WMQConstants.WMQ_CM_CLIENT);
factory.setConnectionNameList("XXX.XXX.XXX.XXX(1414)");
factory.setQueueManager(MQConnectionDetails.QM_NAME);
factory.setChannel(MQConnectionDetails.CHANNEL);
factory.setClientReconnectOptions(WMQConstants.WMQ_CLIENT_RECONNECT);
factory.setClientReconnectTimeout(MQConnectionDetails.RECONNECT_TIMEOUT);
LOGGER.info("Initializing connection to write queue {} on {}:{}...",
MQConnectionDetails.QUEUE,
MQConnectionDetails.HOST,
MQConnectionDetails.PORT);
connection = factory.createConnection();
connection.setExceptionListener(new MQExceptionListener());
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
destination = session.createQueue(MQConnectionDetails.QUEUE);
producer = session.createProducer(destination);
connection.start();
} catch (JMSException ex) {
LOGGER.error("Error initializing connection to write queue", ex);
}
}
public void write(String message) {
try {
TextMessage textMessage = session.createTextMessage(message);
producer.send(textMessage);
} catch (Exception ex) {
LOGGER.error("Error sending message to write queue", ex);
}
}
}
Console Output
2020-02-12 08:39:11,628 INFO [MQWriter2.<init>:29] (main) Initializing connection to write queue DEV.QUEUE.1 on 54.161.121.207:1414...
2020-02-12 08:39:14,552 INFO [Application.run:19] (main) Sending message Hello Testing 1 to MQ server...
2020-02-12 08:39:15,710 INFO [Application.run:19] (main) Sending message Hello Testing 2 to MQ server...
2020-02-12 08:39:16,841 INFO [Application.run:19] (main) Sending message Hello Testing 3 to MQ server...
...
2020-02-12 08:39:41,973 INFO [Application.run:19] (main) Sending message Hello Testing 25 to MQ server...
2020-02-12 08:41:27,314 ERROR [MQExceptionListener.onException:14] (JMSCCThreadPoolWorker-10) =====
2020-02-12 08:41:27,314 ERROR [MQExceptionListener.onException:15] (JMSCCThreadPoolWorker-10) com.ibm.msg.client.jms.DetailedJMSException: JMSWMQ1107: A problem with this connection has occurred.
An error has occurred with the IBM MQ JMS connection.
Use the linked exception to determine the cause of this error.
2020-02-12 08:41:27,314 ERROR [MQWriter2.write:49] (main) Error sending message to write queue
com.ibm.msg.client.jms.DetailedJMSException: JMSWMQ2007: Failed to send a message to destination 'DEV.QUEUE.1'.
JMS attempted to perform an MQPUT or MQPUT1; however IBM MQ reported an error.
Use the linked exception to determine the cause of this error.
at com.ibm.msg.client.wmq.common.internal.Reason.reasonToException(Reason.java:595)
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:215)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.checkJmqiCallSuccess(WMQMessageProducer.java:1288)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.checkJmqiCallSuccess(WMQMessageProducer.java:1245)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.access$800(WMQMessageProducer.java:76)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer$SpiIdentifiedProducerShadow.sendInternal(WMQMessageProducer.java:906)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer$ProducerShadow.send(WMQMessageProducer.java:566)
at com.ibm.msg.client.wmq.internal.WMQMessageProducer.send(WMQMessageProducer.java:1428)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.sendMessage(JmsMessageProducerImpl.java:855)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.synchronousSendInternal(JmsMessageProducerImpl.java:2055)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.sendInternal(JmsMessageProducerImpl.java:1993)
at com.ibm.msg.client.jms.internal.JmsMessageProducerImpl.send(JmsMessageProducerImpl.java:1486)
at com.ibm.mq.jms.MQMessageProducer.send(MQMessageProducer.java:293)
at org.example.MQWriter2.write(MQWriter2.java:47)
at org.example.Application.run(Application.java:20)
at org.example.Application.main(Application.java:11)
Caused by: com.ibm.mq.MQException: JMSCMQ0001: IBM MQ call failed with compcode '2' ('MQCC_FAILED') reason '2009' ('MQRC_CONNECTION_BROKEN').
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:203)
... 14 more
Caused by: com.ibm.mq.jmqi.JmqiException: CC=2;RC=2009
at com.ibm.mq.jmqi.remote.api.RemoteHconn$ReconnectionState.recordFailure(RemoteHconn.java:4931)
at com.ibm.mq.jmqi.remote.api.RemoteHconn.setReconnectionFailureInner(RemoteHconn.java:2650)
at com.ibm.mq.jmqi.remote.api.RemoteParentHconn.setReconnectionFailure(RemoteParentHconn.java:152)
at com.ibm.mq.jmqi.remote.impl.RemoteReconnectThread.bestHconn(RemoteReconnectThread.java:265)
at com.ibm.mq.jmqi.remote.impl.RemoteReconnectThread.run(RemoteReconnectThread.java:115)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueItem.runTask(WorkQueueItem.java:319)
at com.ibm.msg.client.commonservices.workqueue.SimpleWorkQueueItem.runItem(SimpleWorkQueueItem.java:99)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueItem.run(WorkQueueItem.java:343)
at com.ibm.msg.client.commonservices.workqueue.WorkQueueManager.runWorkQueueItem(WorkQueueManager.java:312)
at com.ibm.msg.client.commonservices.j2se.workqueue.WorkQueueManagerImplementation$ThreadPoolWorker.run(WorkQueueManagerImplementation.java:1227)
I faced the same issue as the topic starter. After spending hours sifting information available in the internet, speaking to colleagues and pulling hair in an attempt to make the reconnection work, I gave up and made a decision to work around the problem by emulating that incomprehensible reconnection functionality. I hope it will help other people struggling with IBM MQ. I wrote the class that, basically, does 2 things:
First, here's the class itself:
package com.raiks.mqclient;
import javax.jms.Destination;
import javax.jms.JMSConsumer;
import javax.jms.JMSContext;
import javax.jms.JMSException;
import com.ibm.msg.client.jms.JmsConnectionFactory;
import com.ibm.msg.client.wmq.WMQConstants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.raiks.mqclient.IbmMqMessageListener;
/**
* This class implements the reconnection logic for JMS brokers that don't support it
* In particular, it does it for IBM MQ with its incomprehensible reconnection algorithm
* It's expected that each connection manager receives a separate connection factory
* and a message listener - it's not guaranteed for those to be thread safe
*/
public final class IbmMqJmsConnectionManager {
private static final Logger LOGGER = LoggerFactory.getLogger(IbmMqJmsConnectionManager.class);
private static final int INITIAL_RECONNECTION_DELAY_MS = 6000;
private static final int MAX_RECONNECTION_DELAY_MS = 60000;
private static final String QUEUE_PREIX = "queue:///";
private final String connectorName;
private final JmsConnectionFactory connectionFactory;
private final String queueName;
private final IbmMqMessageListener messageListener;
private final int initialReconnectionDelayMs;
private final int maxReconnectionDelayMs;
public IbmMqJmsConnectionManager(
String connectorName,
JmsConnectionFactory connectionFactory,
String queueName,
IbmMqMessageListener messageListener,
int initialReconnectionDelayMs,
int maxReconnectionDelayMs
) {
this.connectorName = connectorName;
this.connectionFactory = connectionFactory;
this.queueName = queueName;
this.messageListener = messageListener;
this.initialReconnectionDelayMs = initialReconnectionDelayMs;
this.maxReconnectionDelayMs = maxReconnectionDelayMs;
}
/**
* Attempts to connect to a JMS broker and makes continuous retries with an increasing interval if fails
* When the maximum interval is reached, issues an error and keeps on trying
* Sets the exception listener (a callback) in the created JMSContext which calls this method when the
* connection with the broker goes down due to network issue or intentional connection termination
*/
public void connectToBrokerWithRetries() {
String connectionDetails = formatConnectionDetails();
LOGGER.info("Attempting to connect to JMS broker '{}'. Connection details = {}", connectorName, connectionDetails);
JMSContext context = null;
int sleepingTimeMs = INITIAL_RECONNECTION_DELAY_MS;
int accumulatedSleepingTimeMs = 0;
// Try to reconnect until we succeed. IMPORTANT! This is a blocking loop that never ends so it must be run in a separate thread
while (context == null) {
try {
context = connectionFactory.createContext(JMSContext.AUTO_ACKNOWLEDGE);
LOGGER.info("Successfully connected to the JMS broker '{}'. Connection details = {}", connectorName, connectionDetails);
boolean hadUnsuccessfulConnectionAttempts = accumulatedSleepingTimeMs > 0;
if (hadUnsuccessfulConnectionAttempts) {
LOGGER.warn(
"Before this successful attempt, I spent {} ms repeatedly trying to connect to '{}'. Please check the broker's health. Connection details = {}",
accumulatedSleepingTimeMs, connectorName, connectionDetails
);
}
Destination destination = context.createQueue(QUEUE_PREIX + queueName);
JMSConsumer jmsConsumer = context.createConsumer(destination);
jmsConsumer.setMessageListener(messageListener);
LOGGER.info("Successfully connected to the queue '{}' at '{}'. Connection details = {}", queueName, connectorName, connectionDetails);
// Sets a callback that will be invoked when something happens with a connection to a broker
context.setExceptionListener(
jmsException -> {
LOGGER.warn("Something bad happened to JMS broker connection to '{}'. I will try to reconnect. Connection details = {}", connectorName, connectionDetails);
connectToBrokerWithRetries();
}
);
} catch (Exception e) {
LOGGER.warn(
"Failed to create a JMS context for '{}'. I will wait for {} ms and then make a reconnection attempt. Connection details = {}",
connectorName, sleepingTimeMs, connectionDetails, e
);
context = null;
try {
Thread.sleep(sleepingTimeMs);
accumulatedSleepingTimeMs += sleepingTimeMs;
int doubledSleepingTime = sleepingTimeMs * 2;
// We double the sleeping time on each subsequent attempt until we hit the limit
// Then we just keep on reconnecting forever using the limit value
boolean nextReconnectionDelayWillExceedMaxDelay = doubledSleepingTime >= MAX_RECONNECTION_DELAY_MS;
if (nextReconnectionDelayWillExceedMaxDelay) {
sleepingTimeMs = MAX_RECONNECTION_DELAY_MS;
LOGGER.error(
"Repeatedly failed to create a JMS context for {} ms. I will keep on trying every {} ms but please check the broker availability. Connection details = {}",
accumulatedSleepingTimeMs, sleepingTimeMs, connectionDetails
);
} else {
sleepingTimeMs = doubledSleepingTime;
}
} catch (InterruptedException ex) {
throw new RuntimeException(ex);
}
}
}
}
private String formatConnectionDetails() {
String connectionDetails = "[]";
try {
connectionDetails = String.format(
"[ host = %s, port = %d, queueManager = %s, channel = %s, user = %s ]",
connectionFactory.getStringProperty(WMQConstants.WMQ_HOST_NAME),
connectionFactory.getIntProperty(WMQConstants.WMQ_PORT),
connectionFactory.getStringProperty(WMQConstants.WMQ_QUEUE_MANAGER),
connectionFactory.getStringProperty(WMQConstants.WMQ_CHANNEL),
connectionFactory.getStringProperty(WMQConstants.USERID)
);
} catch (Exception e) {
LOGGER.warn("Failed to get the connection details. This is not critical, but the details will be unavailable");
}
return connectionDetails;
}
}
And here's how you use it:
LOGGER.info("Starting the initial connection thread");
Thread cftInitialConnectionThread = new Thread(cftConnectionManager::connectToBrokerWithRetries);
cftInitialConnectionThread.start();