We are using WildFly + HornetQ as our application server and JMS message queue, and have the requirement to be able to pause/resume queues from the application. Is this possible?
This can be done using JMX or using the hornetq core management api.
For the purposes of this example, wildfly 8.1.0.Final was used running the standalone-full-ha profile.
Required Maven Dependencies:
<dependency>
<groupId>org.hornetq</groupId>
<artifactId>hornetq-jms-client</artifactId>
<version>2.4.1.Final</version>
</dependency>
<dependency>
<groupId>org.wildfly</groupId>
<artifactId>wildfly-jmx</artifactId>
<version>8.1.0.Final</version>
</dependency>
Here is a test class demonstrating the use of JmsQueueControl via JMX:
package test.jmx.hornetq;
import org.hornetq.api.jms.management.JMSQueueControl;
import javax.management.*;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
public class WildflyJmsControl {
public static void main(String[] args) {
try {
//Get a connection to the WildFly 8 MBean server on localhost
String host = "localhost";
int port = 9990; // management-web port
String urlString = System.getProperty("jmx.service.url","service:jmx:http-remoting-jmx://" + host + ":" + port);
JMXServiceURL serviceURL = new JMXServiceURL(urlString);
JMXConnector jmxConnector = JMXConnectorFactory.connect(serviceURL, null);
MBeanServerConnection connection = jmxConnector.getMBeanServerConnection();
String queueName = "testQueue"; // use your queue name here
String mbeanObjectName = "jboss.as:subsystem=messaging,hornetq-server=default,jms-queue=" + queueName;
ObjectName objectName = ObjectName.getInstance(mbeanObjectName);
JMSQueueControl jmsQueueControl = (JMSQueueControl) MBeanServerInvocationHandler.newProxyInstance(connection, objectName, JMSQueueControl.class, false);
assert jmsQueueControl != null;
long msgCount = jmsQueueControl.countMessages(null);
System.out.println(mbeanObjectName + " message count: " + msgCount);
jmsQueueControl.pause();
System.out.println("queue paused");
jmsQueueControl.resume();
System.out.println("queue resumed");
jmxConnector.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
To access hornetq management via JMS use:
package test.jms.hornetq;
import org.hornetq.api.core.TransportConfiguration;
import org.hornetq.api.core.client.*;
import org.hornetq.api.core.management.ManagementHelper;
import org.hornetq.core.remoting.impl.invm.InVMConnectorFactory;
public class HornetqService {
public void testPauseResumeQueue() {
// this class needs to run in the same jvm as the wildfly server (i.e. not a remote jvm)
try {
ServerLocator locator = HornetQClient.createServerLocatorWithoutHA(new TransportConfiguration(
InVMConnectorFactory.class.getName()));
ClientSession session = locator.createSessionFactory().createSession();
session.start();
ClientRequestor requester = new ClientRequestor(session, "jms.queue.hornetq.management");
String queueName = "testQueue"; // use your queue name here
// get queue message count
ClientMessage message = session.createMessage(false);
ManagementHelper.putAttribute(message, queueName, "messageCount");
ClientMessage reply = requester.request(message);
int count = (Integer) ManagementHelper.getResult(reply);
System.out.println("There are " + count + " messages in exampleQueue");
// pause the queue
message = session.createMessage(false);
ManagementHelper.putOperationInvocation(message, queueName, "pause");
requester.request(message);
// get queue paused
message = session.createMessage(false);
ManagementHelper.putAttribute(message, queueName, "paused");
reply = requester.request(message);
Object result = ManagementHelper.getResult(reply);
System.out.println("result: " + result.getClass().getName() + " : " + result.toString());
// resume queue
message = session.createMessage(false);
ManagementHelper.putOperationInvocation(message, queueName, "resume");
requester.request(message);
// get queue paused
message = session.createMessage(false);
ManagementHelper.putAttribute(message, queueName, "paused");
reply = requester.request(message);
Object result2 = ManagementHelper.getResult(reply);
System.out.println("result2: " + result2.getClass().getName() + " : " + result2.toString());
requester.close();
session.close();
}catch (Exception e){
System.out.println("Error pausing queue" + e.getMessage());
}
}
}
Are you looking for way to stop and and start delivery of messages? If so, then JMS defines connection.Stop method to pause delivery of messages. Message delivery can be resumed with connection.Start method.
So HornetQ JMS client would have these methods implemented. You will need to use these methods.
Related
I am implementing MQTT Client with Eclipse Paho and has some problems:
Both Publisher and Subscriber connect to broker with qos = 1 and setCleanSession =
false.
My flow:
Connect Subscriber and Publisher to broker, it's ok.
Disconnect Subscriber (I force stop My Project which include Subscriber ), Publisher continuing publishing message.
Reconnect Subscriber -> it cannot connect and throw exception: connectionLost.
If i set qos of Subscriber = 0, it not throw exception but The client does not receive messages sent by the publisher while the subscriber is offline, which I do not want
Can someone help me with this?
This is my code in subcriber
try {
// Create an Mqtt client
MqttAsyncClient mqttClient
= new MqttAsyncClient("tcp://" + swmConfig.getMqttApiLink(), "MeasureTransactionApi");
// new MqttAsyncClient(serverURI, clientId, persistence)
MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setUserName(swmConfig.getMqttUsername());
connOpts.setPassword(swmConfig.getMqttPassword().toCharArray());
connOpts.setCleanSession(false);
// Connect to RabbitMQ Broker
log.info("Connecting to RabbitMQ broker: " + swmConfig.getMqttApiLink());
IMqttToken conToken = mqttClient.connect(connOpts);
conToken.waitForCompletion(10000);
if (!conToken.isComplete() || conToken.getException() != null) {
log.info("Error connecting: " + conToken.getException());
System.exit(-1);
}
log.info("Connected");
// Latch used for synchronizing b/w threads
final CountDownLatch latch = new CountDownLatch(1);
// Callback - Anonymous inner-class for receiving messages
mqttClient.setCallback(new MqttCallback() {
public void messageArrived(String topic, MqttMessage message) {
String time = new Timestamp(System.currentTimeMillis()).toString();
log.info("\nReceived a Message from RabbitMQ Broker" + "\n\tTime: " + time
+ "\n\tTopic: " + topic + "\n\tMessage: "
+ new String(message.getPayload()) + "\n\tQoS: "
+ message.getQos() + "\n");
handleMQTTMessageService.handleMessageArrived(message);
}
public void connectionLost(Throwable cause) {
log.info("Connection to RabbitMQ broker lost!" + cause.getMessage());
latch.countDown();
}
public void deliveryComplete(IMqttDeliveryToken token) {
log.info("deliveryComplete");
}
});
// Subscribe client to the topic filter with QoS level of 1
log.info("Subscribing client to topic: " + topic);
IMqttToken subToken = mqttClient.subscribe(topic, 1);
subToken.waitForCompletion(10000);
if (!subToken.isComplete() || subToken.getException() != null) {
log.info("Error subscribing: " + subToken.getException());
System.exit(-1);
}
} catch (MqttException me) {
log.error("Error:", me);
}
QOS is independent for publishers and subscribers.
To ensure delivery to the subscribing client you need to subscribe at greater than QOS 0.
What happens to QOS 0 subscriptions depends on the broker, by default most will not queue messages for QOS 0 subscriptions, but mosquitto can be forced to with the queue_qos0_messages configuration flag
I have an issue with respect to consuming offline MQTT messages in Moquette server through eclipse Paho client.
Following are the steps which I have followed.
Created and spinned up the Moquette MQTT broker.
Created a simple MQTT consumer application using eclipse Paho client.
Set consumer to consume data on topic : "devices/reported/#" with QOS : 1 and CleanSession : False
Created a simple MQTT data publisher to publish data to MQTT broker using Eclipse Paho.
Used MQTT data publisher to publish messages to : "devices/reported/client_1" topic with QOS : 1
Above steps were successful without any issue.
Then I stopped my consumer application and sent MQTT data to broker with the same topic. using my publisher application - Server was able to receive these messages but in this moment there was no any consumer to consume this message since I have stopped my consumer.
Then I started my consumer application again. It was connected to the broker successfully but, it did not receive any message which I sent to broker while the consumer shutdown.
Do I need to do any specific configuration to my Moquette server to persist data (with clean session : false) ?
Or am I missing something ?
Please find my sample code below,
Moquette Server initialization
package com.gbids.mqtt.moquette.main;
import com.gbids.mqtt.moquette.server.PublishInterceptor;
import io.moquette.interception.InterceptHandler;
import io.moquette.server.Server;
import io.moquette.server.config.IConfig;
import io.moquette.server.config.MemoryConfig;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;
public class ServerLauncher {
public static void main(String[] args) throws IOException {
Properties props = new Properties();
final IConfig configs = new MemoryConfig(props);
final Server mqttBroker = new Server();
final List<? extends InterceptHandler> userHandlers = Arrays.asList(new PublishInterceptor());
mqttBroker.startServer(configs, userHandlers);
System.out.println("moquette mqtt broker started, press ctrl-c to shutdown..");
Runtime.getRuntime().addShutdownHook(new Thread() {
#Override
public void run() {
System.out.println("stopping moquette mqtt broker..");
mqttBroker.stopServer();
System.out.println("moquette mqtt broker stopped");
}
});
}
}
MQTT Consumer
package com.gbids.mqtt.moquette.main;
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
public class ConsumerLauncher implements MqttCallback {
private static final String topicPrefix = "devices/reported";
private static final String broker = "tcp://0.0.0.0:1883";
private static final String clientIdPrefix = "consumer";
public static void main(String[] args) throws MqttException {
final String clientId = "consumer_1";
MqttClient sampleClient = new MqttClient(broker, clientId, new MemoryPersistence());
MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setCleanSession(false);
sampleClient.connect(connOpts);
sampleClient.subscribe(topicPrefix + "/#", 1);
sampleClient.setCallback(new ConsumerLauncher());
}
public void connectionLost(Throwable throwable) {
System.out.println("Consumer connection lost : " + throwable.getMessage());
}
public void messageArrived(String s, MqttMessage mqttMessage) throws Exception {
System.out.println("Message arrived from topic : " + s + " | Message : " + new String(mqttMessage.getPayload()) + " | Message ID : " +mqttMessage.getId());
}
public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
System.out.println("Delivery completed from : " + clientIdPrefix + "_1");
}
}
MQTT Publisher
package com.gbids.mqtt.moquette.main;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
public class ClientLauncher {
private static final String content = "{\"randomData\": 25}";
private static final String willContent = "Client disconnected unexpectedly";
private static final String broker = "tcp://0.0.0.0:1883";
private static final String clientIdPrefix = "client";
public static void main(String[] args) throws Exception{
sendDataWithQOSOne();
System.exit(0);
}
private static void sendDataWithQOSOne(){
try {
final String clientId = "client_1";
MqttClient sampleClient = new MqttClient(broker, clientId, new MemoryPersistence());
MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setCleanSession(false); // for publisher - this is not needed I think
sampleClient.connect(connOpts);
MqttMessage message = new MqttMessage(content.getBytes());
message.setQos(1);
final String topic = "devices/reported/" + clientId;
sampleClient.publish(topic, message);
System.out.println("Message published from : " + clientId + " with payload of : " + content);
sampleClient.disconnect();
} catch (MqttException me) {
me.printStackTrace();
}
}
}
In your case you need to set the retained flag to true when creating the MqttMessage in your ClientLauncher (publisher). The default value is false as in the documentation.
...
message.setRetained(true)
...
Setting this flag enables messages to be retained on the broker and be sent to newly connected clients. Please be aware, that the broker only keeps the last message for a topic. There is no way to keep more than one message for a specific topic.
I started JMS for a week now. I created JMS using Netbeans,maven and glassfish.
I have one producer and one durable consumer and I wanted to add another durable consumer to the same topic(not queue). Is it possible to do so?
because I want all the consumers consume all the message being sent by the producer whether the consumers are offline or not.
Any advice?
Thanks
public class DurableReceive {
#Resource(lookup = "jms/myDurableConnectionFactory")
private static ConnectionFactory connectionFactory;
#Resource(lookup = "jms/myNewTopic")
private static Topic topic;
public static void main(String[] args) {
Destination dest = (Destination) topic;
JMSConsumer consumer;
boolean messageReceived = false;
String message;
System.out.println("Waiting for messages...");
try (JMSContext context = connectionFactory.createContext();) {
consumer = context.createDurableConsumer(topic, "Subscriber1");
while (!messageReceived) {
message = consumer.receiveBody(String.class);
if (message != null) {
System.out.print("Received the following message: " + message);
System.out.println("(Received date: " + new Date() + ")\n");
} else {
messageReceived = true;
}
}
} catch (JMSRuntimeException e) {
System.err.println("##$%RuntimeException occurred: " + e.toString());
System.exit(1);
}
}
}
You can set different clientID for different durable consumers. Jms-broker uses combination of subscriptionName and clientId to identify the unique client (so if your subscriber have unique clientID - it can receive own messages). You can set clientID in your JmsContext.
Background
I'm working of a proof of concept that consist of a server-client system using websocket communication. I use a small jetty solution (jetty-all-9.1.3.v20140225.jar together with servlet-api-3.1.jar). I have most of the basic functionality in order for a PoC.
I have 2 classes:
TestServer (With a main function creating a Server instance, see code)
ClientSocket (WebSocket-object instantiated for each client)
Problem
The problem I would like to discuss has to do with broadcasting client disconnects. The server saves all instances of ClientSockets in one array, the ClientSockets are added to this array in their "onConnect"-function.
The system will later on limit broadcasts to groups of clients, but for the PoC, all connected clients shall get broadcasts. If one client disconnects I want to send a notification to all other clients ("myClient has disconnected." or similar).
To do this I implement a broadcast function in the server that loops through the list of clients, sending this information to all connected clients except the one who disconnected. This function is also used to inform all clients about other things, such as new connections, and this problem should most likely occur here as well in the case a client disconnects at the very same time as someone connects or broadcasts something.
The problem is easy to produced by connecting several (10+) clients (I do it in js) and then disconnect them all at the same time. If I do this I always get concurrency errors, for very few clients (2-3) it works sometimes, depending on timing I guess.
Questions
How should I handle the task of broadcasting to all other clients, taking into account that any clients can disconnect (asynchronously) at any time? Can I do this without generating exceptions? Since it's asynchronous I can't see any other way than dealing with the exceptions occurring. Any suggestions are greatly appreciated.
Code
TestServer.java
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.websocket.server.WebSocketHandler;
import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
public class TestServer {
private static final TestServer testServer = new TestServer();
private ArrayList<ClientSocket> clients = new ArrayList<>();
public static void main(String[] args) throws Exception {
int port = 8080;
Server server = new Server(port);
WebSocketHandler wsHandler = new WebSocketHandler() {
#Override
public void configure(WebSocketServletFactory factory) {
factory.register(ClientSocket.class);
}
};
server.setHandler(wsHandler);
System.out.println("Starting server on port " + port + ".");
server.start();
server.join();
}
public static TestServer getServer() {
return testServer;
}
public void addClient(ClientSocket client) {
this.clients.add(client);
}
public void removeClient(ClientSocket client) {
this.clients.remove(client);
this.broadcast("disconnect " + client.id, client);
}
public void broadcast(String message, ClientSocket excludedClient) {
log("Sending to all clients: " + message);
for (ClientSocket cs : this.clients) {
if (!cs.equals(excludedClient) && cs.session.isOpen() && cs != null) {
try {
cs.session.getRemote().sendStringByFuture(message);
} catch (Exception e) {
log("Error when broadcasting to " + cs.id + " (" + cs.address + "):");
log(e.getMessage());
}
}
}
}
Since looping through an array in this way generally doesn't work if you meddle with the array in the process so I also tried this broadcast function:
public void broadcast(String message, ClientSocket excludedClient) {
log("Sending to all clients: " + message);
Iterator<ClientSocket> cs = this.clients.iterator();
while (cs.hasNext()) {
ClientSocket client = cs.next();
if (client != null) {
if (!client.equals(excludedClient) && client.session.isOpen()) {
try {
client.session.getRemote().sendStringByFuture(message);
} catch (Exception e) {
log("Error when broadcasting to " + client.id + " (" + client.address + "):");
log(e.getMessage());
}
}
}
}
It doesn't work any better though, since the problem is that the array can be meddled with asynchronously if another ClientSocket object disconnects as the first one is broadcasting it's disconnection.
ClientSocket.java
import java.io.IOException;
import org.eclipse.jetty.websocket.api.Session;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketError;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
import org.eclipse.jetty.websocket.api.annotations.WebSocket;
#WebSocket(maxIdleTime=0)
public class ClientSocket {
TestServer server = TestServer.getServer();
Session session;
String id;
String address;
#OnWebSocketClose
public void onClose(Session session, int statusCode, String reason) {
server.log("Disconnected: " + this.id + "(" + this.address + ")" + " (statusCode=" + statusCode + ", reason=" + reason + ")");
server.removeClient(this);
}
#OnWebSocketError
public void onError(Session session, Throwable t) {
server.log(this.id + "(" + this.address + ") error: " + t.getMessage());
}
#OnWebSocketConnect
public void onConnect(Session session) {
this.session = session;
this.address = this.session.getRemoteAddress().getAddress().toString().substring(1);
this.id = this.address; //Until user is registered their id is their IP
server.log("New connection: " + this.address);
server.addClient(this);
try {
session.getRemote().sendString("Hello client with address " + this.address + "!");
} catch (IOException e) {
server.log("Error in onConnect for " + this.id + "(" + this.address + "): " + e.getMessage());
}
}
#OnWebSocketMessage
public void onMessage(Session session, String message) {
server.log("Received from " + this.id + "(" + this.address + "): " + message);
String replyMessage;
String[] commandList = message.split("\\s+");
switch (commandList[0].toLowerCase()) {
case "register":
if (commandList.length > 1) {
this.id = commandList[1];
replyMessage = "Registered on server as " + this.id;
server.broadcast(this.id + " has connected", this);
} else {
replyMessage = "Incorrect register message";
}
break;
default:
replyMessage = "echo " + message;
break;
}
server.log("Sending to " + this.id + "(" + this.address + "): " + replyMessage);
try {
session.getRemote().sendString(replyMessage);
} catch (IOException e) {
server.log("Error during reply in onMessage for " + this.id + "(" + this.address + "): " + e.getMessage());
}
}
}
I pasted this whole class for completeness, even though I removed some of the cases in the switch for onMessage. The parts to take notice in however are the onConnect and onClose functions that will populate and remove clients from the client array in the server.
Error log
[2014-04-17 17:40:17.961] Sending to all clients: disconnect testclient4
2014-04-17 17:40:17.962:WARN:ClientSocket:qtp29398564-17: Unhandled Error (closing connection)
org.eclipse.jetty.websocket.api.WebSocketException: Cannot call method public void ClientSocket#onClose(org.eclipse.jetty.websocket.api.Session, int, java.lang.String) with args: [org.eclipse.jetty.websocket.common.WebSocketSession, java.lang.Integer, <null>]
at org.eclipse.jetty.websocket.common.events.annotated.CallableMethod.call(CallableMethod.java:99)
at org.eclipse.jetty.websocket.common.events.annotated.OptionalSessionCallableMethod.call(OptionalSessionCallableMethod.java:68)
at org.eclipse.jetty.websocket.common.events.JettyAnnotatedEventDriver.onClose(JettyAnnotatedEventDriver.java:122)
at org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:125)
at org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:302)
at org.eclipse.jetty.websocket.common.extensions.AbstractExtension.nextIncomingFrame(AbstractExtension.java:163)
at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.nextIncomingFrame(PerMessageDeflateExtension.java:92)
at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.incomingFrame(PerMessageDeflateExtension.java:66)
at org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:210)
at org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:219)
at org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:257)
at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.read(AbstractWebSocketConnection.java:500)
at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:409)
at org.eclipse.jetty.io.AbstractConnection$1.run(AbstractConnection.java:505)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:607)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:536)
at java.lang.Thread.run(Thread.java:744)
Caused by:
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.eclipse.jetty.websocket.common.events.annotated.CallableMethod.call(CallableMethod.java:71)
at org.eclipse.jetty.websocket.common.events.annotated.OptionalSessionCallableMethod.call(OptionalSessionCallableMethod.java:68)
at org.eclipse.jetty.websocket.common.events.JettyAnnotatedEventDriver.onClose(JettyAnnotatedEventDriver.java:122)
at org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:125)
at org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:302)
at org.eclipse.jetty.websocket.common.extensions.AbstractExtension.nextIncomingFrame(AbstractExtension.java:163)
at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.nextIncomingFrame(PerMessageDeflateExtension.java:92)
at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.incomingFrame(PerMessageDeflateExtension.java:66)
at org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:210)
at org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:219)
at org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:257)
at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.read(AbstractWebSocketConnection.java:500)
at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:409)
at org.eclipse.jetty.io.AbstractConnection$1.run(AbstractConnection.java:505)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:607)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:536)
at java.lang.Thread.run(Thread.java:744)
Caused by:
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
at java.util.ArrayList$Itr.next(ArrayList.java:831)
at TestServer.broadcast(TestServer.java:61)
at TestServer.removeClient(TestServer.java:45)
at ClientSocket.onClose(ClientSocket.java:22)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.eclipse.jetty.websocket.common.events.annotated.CallableMethod.call(CallableMethod.java:71)
at org.eclipse.jetty.websocket.common.events.annotated.OptionalSessionCallableMethod.call(OptionalSessionCallableMethod.java:68)
at org.eclipse.jetty.websocket.common.events.JettyAnnotatedEventDriver.onClose(JettyAnnotatedEventDriver.java:122)
at org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:125)
at org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:302)
at org.eclipse.jetty.websocket.common.extensions.AbstractExtension.nextIncomingFrame(AbstractExtension.java:163)
at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.nextIncomingFrame(PerMessageDeflateExtension.java:92)
at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.incomingFrame(PerMessageDeflateExtension.java:66)
at org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:210)
at org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:219)
at org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:257)
at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.read(AbstractWebSocketConnection.java:500)
at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:409)
at org.eclipse.jetty.io.AbstractConnection$1.run(AbstractConnection.java:505)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:607)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:536)
at java.lang.Thread.run(Thread.java:744)
[2014-04-17 17:40:17.97] testclient7(94.246.80.30) error: Cannot call method public void ClientSocket#onClose(org.eclipse.jetty.websocket.api.Session, int, java.lang.String) with args: [org.eclipse.jetty.websocket.common.WebSocketSession, java.lang.Integer, <null>]
This happens, sometimes for several clients, when disconnecting all the clients at the same time. I'm pretty sure that it has to do with ClientSocket objects disappearing at the same time as a broadcast is made.
Replace:
private ArrayList<ClientSocket> clients = new ArrayList<>();
With:
private List<ClientSocket> clients = new CopyOnWriteArrayList<>();
In your broadcast method just use the for each statement:
for( ClientSocket client : clients )
{
if ( !client.equals(excludedClient) && client.session.isOpen() )
{
// Broadcast...
}
}
This will give you thread safe iteration. ConcurrentModificationException occurs because you are modifying the List at the same time as iterating over it. A CopyOnWriteArrayList copies the internal array on write so modifications do not interfere with iteration. This adds some additional overhead to mutating the list of course, so you may want to think about another method of ensuring thread safety, however I suspect this will be sufficient for your needs. If reads are a lots more common than writes (as is usually the case) then a 'copy on write' data structure will do fine.
Good morning, I have the following code:
int numero = 22492;
String PhnNoStr = String.valueOf (numero);
String transaction = WriteText(tipoTransacao);
String SmsStr = "ECART" + "" + transaction + idToken;
System.out.println ("Message:" + smsStr);
MessageConnection msgCon = null;
msgCon = (MessageConnection) Connector.open ("sms :/ /" + + phnNoStr ": 500");
TextMessage TxtMsg = (TextMessage) msgCon.newMessage (MessageConnection.TEXT_MESSAGE);
txtMsg.setPayloadText (smsStr);
msgCon.send (TxtMsg);
so I send that message by default it returns me a message. I can send and receive this message, however I need to intercept when I receive this message, does anyone know how I can do this?
Thank you
You can use PushRegistry to have your midlet launched when a SMS is received and midlet is not running.
PushRegistry.registerConnection("sms://:500", "your_package.Your_MIDlet", "*");
To handle incoming SMS, you need to open connection and listen for incoming message, eg:
class SMSHandler implements MessageListener, Runnable {
public void start() {
...
connection = (MessageConnection) Connector.open("sms://:500", Connector.READ);
connection.setMessageListener(this);
}
public void notifyIncomingMessage(MessageConnection messageConnection) {
(new Thread(this)).start();
}
public void run() {
final Message message = connection.receive();
...
}
(The reason for processing the message in another thread is that blocking I/O should not be done in system callback - at least WTK emulator will print warning, and on some phones midlet will just freeze).