I'm using rabbitMQ in order to send tasks to workers (consumers) which are created on the run. Currently, each time a new task is created, a new worker is created. The problem goes like that :
-A user creates a task
-A worker is created then the task is sent on the queue for the workers to process
-The worker starts processing the queue (the worker basically sleeps for a time)
-Another user creates a task
-New worker is created and task sent on the queue
-The new worker doesn't process the new task and does absolutly nothing meanwhile, and the new task is processed by the first worker once he's done with the first task
I've checked on the admin part of rabbitmq and there are two consumers bound to the queue, but one of them seems to do all the work while the other just waits.
Here's the code for the worker:
public class Worker extends Thread {
private final static String QUEUE_NAME = "Tasks";
private final static String QUEUE_COMPL = "Completed";
public static int id = 0;
private static final String EXCHANGE_NAME = "logs";
public int compteur;
String identifier;
public Worker() {
Worker.id++;
compteur = id;
}
public void run() {
try {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
channel.basicQos(1);
final Consumer consumer = new DefaultConsumer(channel) {
#Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
String message = new String(body, "UTF-8");
System.out.println("WORKER " + compteur + " : Message received :" + message);
String taskName = message.split(" ")[0];
String length = message.split(" ")[1];
try {
System.out.println("WORKER " + compteur + " : Commencing job :" + message);
doWork(length);
System.out.println("WORKER " + compteur + " : Job's finished :" + message);
taskName += " done by " + compteur;
// confirm(taskName);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
System.out.println("WORKER " + compteur + " : Waiting for a new task...");
}
}
};
channel.basicConsume(QUEUE_NAME, true, consumer);
} catch (IOException ex) {
Logger.getLogger(Worker.class.getName()).log(Level.SEVERE, null, ex);
} catch (TimeoutException ex) {
Logger.getLogger(Worker.class.getName()).log(Level.SEVERE, null, ex);
}
}
private static void doWork(String taskLength) throws InterruptedException {
int temps = Integer.parseInt(taskLength);
Thread.sleep(temps);
}
}
and the code for the part which puts the messages into the queue:
public class serveurSD {
private final static String QUEUE_NAME = "Tasks";
private Manager MANAGER = new Manager();
#WebMethod(operationName = "processTask")
public String processTask(#WebParam(name = "message") String txt, #WebParam(name = "duree") int duree) throws IOException, TimeoutException {
if (MANAGER == null){
MANAGER= new Manager();
MANAGER.listen();
}
System.out.println("SERVER : Message received : " + txt + " " + duree);
MANAGER.giveTask();
ConnectionFactory factory = new ConnectionFactory();
String message = txt + " " + duree;
System.out.println("SERVER : Sending message to workers : " + message);
factory.setHost("localhost");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
channel.close();
connection.close();
return "Your task is being processed";
}
}
(Manager is the class creating the workers on the go.)
I'm sorry if a similar question has already been asked but I couldn't find it.
Thanks for any possible help :)
the second parameter of the basicConsume method is "auto acknowledge". Having this parameter set to true means the consumer will tell RabbitMQ that the message has been acknowledged, as soon as it receives the message.
When the consumer is set to autoAck true, it is highly likely that it will immediately receive the next available message from the queue, even when basicQos is set to 1. this happens, because the 1 limit is immediately decremented by the consumer, to say it no longer has any message and it can accept the next one.
Changing the auto ack parameter to false prevents this problem, when combined with the basic QoS setting of 1, because it forces your consumer to say "hey, i've got a message and i'm currently working on it. don't send me anything else until i'm done."
this allows the other consumer to say "hey, i have a spot open. go ahead and send me the message"
Okay, I seem to have found a way to make it work, problem is I don't know why it works, so if anyone knows, I'd be glad to have an explanation
I changed the second argument of channel.basicConsume(QUEUE_NAME, true, consumer); to false, but I'm not sure to have understood why does it fix my problem.
Related
Would be super grateful if someone can explain me how wait/notify/notifyAll works and if is there better solution for the problem I am facing. Basically, we have to send a bunch of SMS messages. For sending messages an object called SMPPSession is used but in this example I'll just use superficial code. SMPPSession is supposed to send messages to SMSC server and to reestablish session in situations when connection breaks. I would like to use multiple threads for sending multiple messages, and to have a separate single thread, some sort of "guardian"/ "watcher"/"notifier". The role of that separate thread is to stop all other threads from executing their code, while it works on reestablishing session. Naturally, SMPPSession is shared among all these threads. Once that guardian finishes reconnecting, all other thread needs to continue with using the session and proceed with sending.
Now, I have some code and getting exception. Any help?
In reality we do send real SMS messages using jsmpp library and inside it there is SMPPSession object.
public class SMPPSession {
private boolean bind;
private static final Random idGenerator = new Random();
public int sendMessage(String msg){
try{
Thread.sleep(1000L);
System.out.println("Sending message: " + msg);
return Math.abs(idGenerator.nextInt());
} catch (InterruptedException e){
e.printStackTrace();
}
return -1;
}
public void reBind(){
try{
System.out.println("Rebinding...");
Thread.sleep(1000L);
this.bind = true;
System.out.println("Session established!");
} catch (InterruptedException e){
e.printStackTrace();
}
}
public boolean isBind(){
return this.bind;
}
}
public class Sender extends Thread{
private SMPPSession smppSession;
public Sender(String name, SMPPSession smppSession){
this.setName(name);
this.smppSession = smppSession;
}
#Override
public void run(){
while (!Client.messages.isEmpty()){
synchronized (Client.messages){
if (smppSession.isBind()){
final String msg = Client.messages.remove(0);
final int msgId = smppSession.sendMessage(msg);
System.out.println(Thread.currentThread().getName() + " sent msg and received msgId: " + msgId);
Client.messages.notifyAll();
} else {
try {
Client.messages.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
}
}
}
public class SessionProducer extends Thread{
private SMPPSession smppSession;
public SessionProducer(String name, SMPPSession smppSession){
this.setName(name);
this.smppSession = smppSession;
}
#Override
public void run(){
while (!Client.messages.isEmpty()){
synchronized (Client.messages){
if (!smppSession.isBind()){
smppSession.reBind();
System.out.println(Thread.currentThread().getName() + " managed to reestablish SMPP session.");
Client.messages.notifyAll();
} else{
try {
Client.messages.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
}
}
}
public class Client {
public static final List<String> messages = new CopyOnWriteArrayList<>();
public static void main(String[] args) {
//populate messages from db
messages.add("msg1"); messages.add("msg2"); messages.add("msg3"); messages.add("msg4"); messages.add("msg5"); messages.add("msg6");
SMPPSession smppSession = new SMPPSession();
SessionProducer sessionProducer = new SessionProducer("SessionProducer1", smppSession);
Sender sender1 = new Sender("Sender1", smppSession);
Sender sender2 = new Sender("Sender2", smppSession);
Sender sender3 = new Sender("Sender3", smppSession);
Sender sender4 = new Sender("Sender4", smppSession);
sessionProducer.start();
sender1.start();
sender2.start();
sender3.start();
sender4.start();
}
}
Naturally, I get exception and have no idea why. Somehow threads are not in sync.
Rebinding...
Session established!
SessionProducer1 managed to reestablish SMPP session.
Sending message: msg1
Sender4 sent msg and received msgId: 432995458
Sending message: msg2
Sender4 sent msg and received msgId: 113629699
Sending message: msg3
Sender4 sent msg and received msgId: 611735717
Sending message: msg4
Sender4 sent msg and received msgId: 1234995659
Sending message: msg5
Sender4 sent msg and received msgId: 922228968
Sending message: msg6
Sender4 sent msg and received msgId: 2097204472
Exception in thread "Sender2" Exception in thread "Sender1" Exception in thread "Sender3" java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
at java.base/java.util.concurrent.CopyOnWriteArrayList.elementAt(CopyOnWriteArrayList.java:385)
at java.base/java.util.concurrent.CopyOnWriteArrayList.remove(CopyOnWriteArrayList.java:478)
at demo.Sender.run(Sender.java:20)
java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
at java.base/java.util.concurrent.CopyOnWriteArrayList.elementAt(CopyOnWriteArrayList.java:385)
at java.base/java.util.concurrent.CopyOnWriteArrayList.remove(CopyOnWriteArrayList.java:478)
at demo.Sender.run(Sender.java:20)
java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
at java.base/java.util.concurrent.CopyOnWriteArrayList.elementAt(CopyOnWriteArrayList.java:385)
at java.base/java.util.concurrent.CopyOnWriteArrayList.remove(CopyOnWriteArrayList.java:478)
at demo.Sender.run(Sender.java:20)
Your loops call Client.messages.isEmpty() with no synchronization. I haven't spent the time to really understand what your code does—can't see all of it anyway—but I can guess what's happening.
Maybe the list contains one message.
Four threads all see it as not empty.
Four threads all try enter the synchronized(Client.messages) block.
One-by-one, they get in to the block, see that smppSession.isBind() is true, and try to remove a message from the list.
The first thread to remove a message succeeds, and then each of the other four throws an exception because it tried to remove from an empty list.
Recommend a SMS development library sms-client from China to support Smpp.
<dependency>
<groupId>com.chinamobile.cmos</groupId>
<artifactId>sms-client</artifactId>
<version>0.0.7</version>
</dependency>
public void testsmpp() throws Exception {
SmsClientBuilder builder = new SmsClientBuilder();
SmsClient smsClient = builder.uri("smpp://127.0.0.1:18890?username=test01&password=1qaz2wsx&version=52&window=32&maxchannel=1")
.receiver(new MessageReceiver() {
public void receive(BaseMessage message) {
logger.info("receive : {}",message.toString());
}
}).build();
for (int i = 0; i < 5; i++) {
SubmitSm pdu = new SubmitSm();
pdu.setRegisteredDelivery((byte)1);
pdu.setSourceAddress(new Address((byte)0,(byte)0,"10086"));
pdu.setDestAddress(new Address((byte)0,(byte)0,"13800138000"));
pdu.setSmsMsg(new SmsTextMessage("SmsTextMessage " + i,SmsDcs.getGeneralDataCodingDcs(SmsAlphabet.GSM,SmsMsgClass.CLASS_UNKNOWN)));
try {
smsClient.send(pdu, 1000);
} catch (Exception e) {
logger.info("send ", e);
}
}
Thread.sleep(5000000);
}
In my application I have 3 classes:
- Company, which hires Workers for any of 3 jobs
- Workers, each can do 2 jobs
- Administrator, which receives copies of all messages in the program and can send messages to all companies, all workers or just everyone
I'm using work.companies.companyName for companies keys and work.workers.workerName for workers keys, they both use default exchange and queue for communication. The Administrator receives messages with admin Topic Exchange.
The problem is with the Administrator -> everyone else communication. It works exactly like Direct exchange - I can get Companies and Workers any names, even like "#", "company1.#" etc. and they won't receive anything, unless in the Administrator I explicitly send the message with key like "work.companies.company1".
I would like to be able to use just e. g. "work.companies.#" to send message to all companies. What am I doing wrong?
Administrator.java:
public class Administrator
{
public static void main(String[] args) throws IOException, TimeoutException
{
new Thread(new TopicListener("admin", ign -> {})).start();
TopicWriter writer = new TopicWriter();
// lots of code
TopicListener.java:
public class TopicListener implements Runnable
{
private final String EXCHANGE_NAME = "space";
private String key;
private Consumer<String> msgHandler;
public TopicListener(String key, Consumer<String> msgHandler)
{
this.key = key;
this.msgHandler = msgHandler;
}
#Override
public void run()
{
try
{
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, "topic");
String queueName = channel.queueDeclare().getQueue();
channel.queueBind(queueName, EXCHANGE_NAME, key);
com.rabbitmq.client.Consumer consumer = new DefaultConsumer(channel)
{
#Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body)
{
String msg = new String(body, StandardCharsets.UTF_8);
System.out.println("Received: \"" + msg + "\"");
msgHandler.accept(msg);
}
};
channel.basicConsume(queueName, true, consumer);
}
catch (IOException | TimeoutException e)
{ e.printStackTrace(); }
}
}
TopicWriter.java:
public class TopicWriter
{
private final String EXCHANGE_NAME = "space";
private final Channel channel;
public TopicWriter() throws IOException, TimeoutException
{
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
Connection connection = factory.newConnection();
this.channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, "topic");
}
public void send(String msg, String key) throws IOException
{
channel.basicPublish(
EXCHANGE_NAME,
key,
null,
msg.getBytes(StandardCharsets.UTF_8));
}
}
Company.java contains:
new Thread(new TopicListener("space.agencies." + agencyID, ign -> {})).start();
Worker.java contains:
new Thread(new TopicListener("space.carriers." + carrierID, consumer)).start();
I found out where the problem was: I was trying to send message to everyone using Topic, where in RabbitMQ Topic is used to specify who should receive the message. The "#" or "*" should be used in the queue key declaration, not while sending the message with a given key.
So I wrote a program where I have a email table and it contains columns such as id,user,recipient,content,subject,etc. I would be running this as a backend service for 24/7 to keep fetching records to keep sending emails.
It's something like this:
public void schedule(){
Thread service;
service = new Thread(new Runnable() {
public void run() {
try {
System.out.println("Email service is ready");
email();
} catch (Exception e) {
e.printStackTrace();
}
}
});
service.start();
}
public void email() throws Exception {
try{
while(true) {
readConfig();
String portNumber = (String) settingsMap.get("COBRA_PORT");
if (ejbCon.checkConnection(portNumber) == -1) {
TerminalLogger.printMsg("failed to init EJB Beans on cobra port : " + portNumber);
stop = true;
}
List<Emailqueue> emailList=ejbCon.getSettingsFacade().emailrecord();
for (Emailqueue obj : emailList) {
String emailStatus = "DONE";
String errormsg=sendEmail(obj.getRecipient(), obj.getSubject(), obj.getContent(),obj.getUlnodeid(),obj.getUser());
if (!errormsg.equals("")) {
emailStatus = "FAILED";
}
TerminalLogger.printMsg("Status : " + emailStatus);
}
}
}catch(Exception e){
e.printStackTrace();
TerminalLogger.printMsg("Exception: "+e.toString());
}
Thread.sleep(2000);
}
So in email method,it fetches record from the table where the status are 'pending' and get it's relevant values and pass them as parameters.So if there are two pending records,it will fetch them and for loop each to send to their respectively recipient. It works fine.
However,I kept the program running and I tried inserting new record to the table but it is not picking it up.There's no error too.I thought while(true) always keep picking up records from the table if there are pending email records.
Did I do any mistake?
Edit:
Apparently the while loop keeps running and picking newly inserted records when I implemented with JDBC but with JPA(in this case),it does not keep looping.
Edit 2:
Apparently, the while(true) works now and I have no idea why. Although,the program will throw an communication timeout error after a period of time,probably because there's no record. Would need to resolve that.
This is how the loop looks like now:
try{
while(true) {
readConfig();
String portNumber = (String) settingsMap.get("COBRA_PORT");
if (ejbCon.checkConnection(portNumber) == -1) {
TerminalLogger.printMsg("failed to init EJB Beans on cobra port : " + portNumber);
stop = true;
}
List<Emailqueue> emailList=ejbCon.getSettingsFacade().emailrecord();
for (Emailqueue obj : emailList) {
String emailStatus = "DONE";
String errormsg=sendEmail(obj.getRecipient(), obj.getSubject(), obj.getContent(),obj.getUlnodeid(),obj.getUser());
if (!errormsg.equals("")) {
emailStatus = "FAILED";
}
TerminalLogger.printMsg("Status : " + emailStatus);
}
Thread.sleep(2000);
}
I think its prefer use cron scheduler rather than using while(true) inside of thread. it will be more safe than while(true) itself.
I took the example from here http://www.rabbitmq.com/tutorials/tutorial-six-java.html, added one more RPC call from RPCClient and added some logging into stdout. As a result, when the second call is executed, rabbitmq uses the consumer with wrong correlation id which is not expected behavior. Is it a bug or am I getting anything wrong?
RPCServer:
package com.foo.rabbitmq;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Envelope;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class RPCServer {
private static final String RPC_QUEUE_NAME = "sap-consume";
private static int fib(int n) {
if (n ==0) return 0;
if (n == 1) return 1;
return fib(n-1) + fib(n-2);
}
public static void main(String[] argv) {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = null;
try {
connection = factory.newConnection();
final Channel channel = connection.createChannel();
channel.queueDeclare(RPC_QUEUE_NAME, false, false, false, null);
channel.basicQos(1);
System.out.println(" [x] Awaiting RPC requests");
Consumer consumer = new DefaultConsumer(channel) {
#Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
AMQP.BasicProperties replyProps = new AMQP.BasicProperties
.Builder()
.correlationId(properties.getCorrelationId())
.build();
String response = "";
try {
String message = new String(body,"UTF-8");
int n = Integer.parseInt(message);
System.out.println(" [.] fib(" + message + ")");
response += fib(n);
}
catch (RuntimeException e){
System.out.println(" [.] " + e.toString());
}
finally {
channel.basicPublish( "", properties.getReplyTo(), replyProps, response.getBytes("UTF-8"));
channel.basicAck(envelope.getDeliveryTag(), false);
// RabbitMq consumer worker thread notifies the RPC server owner thread
synchronized(this) {
this.notify();
}
}
}
};
channel.basicConsume(RPC_QUEUE_NAME, false, consumer);
// Wait and be prepared to consume the message from RPC client.
while (true) {
synchronized(consumer) {
try {
consumer.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
} catch (IOException | TimeoutException e) {
e.printStackTrace();
}
finally {
if (connection != null)
try {
connection.close();
} catch (IOException _ignore) {}
}
}
}
RPCCLient:
package com.bar.rabbitmq;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Envelope;
import java.io.IOException;
import java.util.UUID;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeoutException;
public class RPCClient {
private Connection connection;
private Channel channel;
private String requestQueueName = "sap-consume";
private String replyQueueName;
public RPCClient() throws IOException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
connection = factory.newConnection();
channel = connection.createChannel();
replyQueueName = channel.queueDeclare().getQueue();
}
public String call(String message) throws IOException, InterruptedException {
final String corrId = UUID.randomUUID().toString();
AMQP.BasicProperties props = new AMQP.BasicProperties
.Builder()
.correlationId(corrId)
.replyTo(replyQueueName)
.build();
channel.basicPublish("", requestQueueName, props, message.getBytes("UTF-8"));
final BlockingQueue<String> response = new ArrayBlockingQueue<String>(1);
channel.basicConsume(replyQueueName, true, new DefaultConsumer(channel) {
#Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
if (properties.getCorrelationId().equals(corrId)) {
System.out.println("Correlation Id" + properties.getCorrelationId() + " corresponds to expected one.");
response.offer(new String(body, "UTF-8"));
} else {
System.out.println("Correlation Id" + properties.getCorrelationId() + " doesn't correspond to expected one " + corrId);
}
}
});
return response.take();
}
public void close() throws IOException {
connection.close();
}
public static void main(String[] argv) {
RPCClient rpc = null;
String response = null;
try {
rpc = new RPCClient();
System.out.println(" [x] Requesting fib(30)");
response = rpc.call("30");
System.out.println(" [.] Got '" + response + "'");
System.out.println(" [x] Requesting fib(40)");
response = rpc.call("40");
System.out.println(" [.] Got '" + response + "'");
} catch (IOException | TimeoutException | InterruptedException e) {
e.printStackTrace();
} finally {
if (rpc != null) {
try {
rpc.close();
} catch (IOException _ignore) {
}
}
}
}
}
Yes you found a bug in the tutorial code. I have opened a pull request to fix it here and you can find the explanation of what's happening as well:
https://github.com/rabbitmq/rabbitmq-tutorials/pull/174
NOTE: the RabbitMQ team monitors the rabbitmq-users mailing list and only sometimes answers questions on StackOverflow.
This example is simplistic: it uses one queue for the reply. By sending a second request, you register a new consumer to the reply, but the consumer of the first request is still listening and actually steals the response of the second request. That's why the client seems to use the same correlation ID.
We updated the client code to use an exclusive, auto-delete queue for each request. This queue will be auto-deleted by the server because its only consumer is unsubscribed after the response has been received. This is a bit more involved but closer to a real-world scenario.
Note the best way to deal with the reply queue with RabbitMQ is to use direct reply-to. This uses pseudo-queues which are lighter than real queues. We don't mention direct reply-to in the tutorial to keep it as simple as possible, but this is the preferred feature to use in production.
I use snmp4j ver 1.10.1 from org.snmp4j and this is my trap receiver code to catch data from snmp trap.
public class TrapReceiver extends Thread implements CommandResponder {
//#Autowired
private CarService carService;
List<PDUv1> listPdu = new ArrayList<PDUv1>();
List<PDUv1> temp = new ArrayList<PDUv1>();
String message = "";
int totReceivedTrap = 0;
public TrapReceiver(CarService carService){
this.carService = carService;
}
public synchronized void processPdu(CommandResponderEvent cmdRespEvent) {
PDUv1 pdu = (PDUv1) cmdRespEvent.getPDU();
if (pdu != null) {
System.out.println(pdu.getVariableBindings().toString());
}
totReceivedTrap++;
System.out.println("total received trap "+totReceivedTrap);
}
public void run() {
while (true) {
try {
this.listen(new UdpAddress("192.168.1.5/162")); //alamat PDU akan listen
} catch (Exception e) {
e.printStackTrace();
}
}
}
public synchronized void listen(TransportIpAddress address) throws IOException {
AbstractTransportMapping transport;
if (address instanceof TcpAddress) {
transport = new DefaultTcpTransportMapping((TcpAddress) address);
} else {
transport = new DefaultUdpTransportMapping((UdpAddress) address);
}
ThreadPool threadPool = ThreadPool.create("DispatcherPool", 10);
MessageDispatcher mDispathcher = new MultiThreadedMessageDispatcher(
threadPool, new MessageDispatcherImpl());
// add message processing models
mDispathcher.addMessageProcessingModel(new MPv1());
mDispathcher.addMessageProcessingModel(new MPv2c());
// add all security protocols
SecurityProtocols.getInstance().addDefaultProtocols();
SecurityProtocols.getInstance().addPrivacyProtocol(new Priv3DES());
// Create Target
CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
Snmp snmp = new Snmp(mDispathcher, transport);
snmp.addCommandResponder(this);
transport.listen();
message ="Listening on " + address;
System.out.println(message);
try {
this.wait();
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
public String getMessage(){
return this.message;
}
}
But one variable value is missing, the value of this variable is latitude and longitude (format : -903849323.20384;+230349402.03000). And when i catch the data using wireshark, I got the value is missing too.
The screenshot
http://www.mediafire.com/view/?kjz1drb9jhda88a
http://www.mediafire.com/view/?ov6lqn6u9n669my
Why the data is null, what wrong.
If you do not see the value inside the packet captured by wireshark, then it is completely valid that you get the null value in the code. What else would you expect?
This seems to be more likely a problem/feature of the SNMP agent running on the device (e.g. geo location was not set, GPS signal is not available, etc.)