public void publish(String topicName, int qos, byte[] payload) throws MqttException {
final MqttTopic topic = client.getTopic(topicName);
final MqttMessage message = new MqttMessage(payload);
topic.publish(message);
System.out.println("Published data. Topic: " + topic.getName() + " Message: " + payload);
}
void repeatedlyPub() {
String methodName = Utility.getMethodName();
int i = 0;
while (mqttClient.isConnected()) {
try {
if (i > 999999) {
i = 0;
}
byte[] payload =
("Message payload " + getClass().getName() + ".publish" + (i++)).getBytes();
MqttTopic mqttTopic = mqttClient.getTopic(FirstSubTopicString);
log.info("Publishing to..." + FirstSubTopicString);
mqttTopic.publish(payload, 1, false);
} catch (Exception exception) {
log.fine("Caught exception:" + exception);
// Don't fail - we are going to get an exception as we disconnected during takeOver
// Its likely the publish rate is too high i.e. inflight window is full
}
}
}
/**
* Test that a client actively doing work can be taken over
*
* @throws Exception
*/
@Test
public void testLiveTakeOver() throws Exception {
String methodName = Utility.getMethodName();
LoggingUtilities.banner(log, cclass, methodName);
log.entering(className, methodName);
IMqttClient mqttClient = null;
try {
FirstClient firstClient = new FirstClient();
Thread firstClientThread = new Thread(firstClient);
log.info("Starting the firstClient thread");
firstClientThread.start();
log.info("firstClientThread Started");
firstClient.waitForState(FirstClientState.READY);
log.fine("telling the 1st client to go and let it publish for 2 seconds");
// Tell the first client to go and let it publish for a couple of seconds
firstClient.setState(FirstClientState.RUNNING);
Thread.sleep(2000);
log.fine("Client has been run for 2 seconds, now taking over connection");
// Now lets take over the connection
// Create a second MQTT client connection with the same clientid. The
// server should spot this and kick the first client connection off.
// To do this from the same box the 2nd client needs to use either
// a different form of persistent store or a different locaiton for
// the store to the first client.
// MqttClientPersistence persist = new MemoryPersistence();
mqttClient = clientFactory.createMqttClient(serverURI, ClientId, null);
MqttV3Receiver mqttV3Receiver =
new MqttV3Receiver(mqttClient, LoggingUtilities.getPrintStream());
mqttClient.setCallback(mqttV3Receiver);
MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
mqttConnectOptions.setCleanSession(false);
mqttConnectOptions.setWill("WillTopic", "payload".getBytes(), 2, true);
log.info("Connecting...(serverURI:" + serverURI + ", ClientId:" + ClientId);
mqttClient.connect(mqttConnectOptions);
// We should have taken over the first Client's subscription...we may have some
// of his publishes arrive.
// NOTE: as a different persistence is used for the second client any inflight
// publications from the client will not be recovered / restarted. This will
// leave debris on the server.
log.fine(
"We should have taken over the first Client's subscription...we may have some of his publishes arrive.");
// Ignore his publishes that arrive...
ReceivedMessage oldMsg;
do {
oldMsg = mqttV3Receiver.receiveNext(1000);
} while (oldMsg != null);
log.fine("Now check we have grabbed his subscription by publishing..");
// Now check we have grabbed his subscription by publishing..
byte[] payload =
("Message payload from second client " + getClass().getName() + "." + methodName)
.getBytes();
MqttTopic mqttTopic = mqttClient.getTopic(FirstSubTopicString);
log.info("Publishing to..." + FirstSubTopicString);
mqttTopic.publish(payload, 1, false);
log.info("Publish sent, checking for receipt...");
boolean ok = mqttV3Receiver.validateReceipt(FirstSubTopicString, 1, payload);
if (!ok) {
throw new Exception("Receive failed");
}
} catch (Exception exception) {
log.throwing(className, methodName, exception);
throw exception;
} finally {
try {
mqttClient.disconnect();
log.info("Disconnecting...");
mqttClient.close();
log.info("Close...");
} catch (Exception exception) {
log.throwing(className, methodName, exception);
throw exception;
}
}
log.exiting(className, methodName);
}