I am trying to access a jedis client with multiple threads where one thread can simple read and write to the database while the other thread can subscribe and a listen to a channel . Is this possible in jedis . Or if it is possible to write variables to one client by any other client that would also work.
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPubSub;
public class Testing1 {
public static void main(String args[])
{
final Jedis jedis = new Jedis("localhost");
Runnable runnable =()->
{
System.out.println(jedis.clientId());
jedis.set("acd","acg");
String str=jedis.get("acd");
System.out.println(str);
};
Runnable runnable2 =()->
{
System.out.println(jedis.clientId());
JedisPubSub jedisPubSub = new JedisPubSub()
{
#Override
public void onMessage(String channel, String message) {
System.out.println("Channel " + channel + " has sent a message : " + message );
if(channel.equals("C1")) {
/* Unsubscribe from channel C1 after first message is received. */
unsubscribe(channel);
}
}
#Override
public void onSubscribe(String channel, int subscribedChannels) {
System.out.println("Client is Subscribed to channel : "+ channel);
System.out.println("Client is Subscribed to "+ subscribedChannels + " no. of channels");
}
#Override
public void onUnsubscribe(String channel, int subscribedChannels) {
System.out.println("Client is Unsubscribed from channel : "+ channel);
System.out.println("Client is Subscribed to "+ subscribedChannels + " no. of channels");
}
};
jedis.subscribe(jedisPubSub, "__redis__:invalidate");
};
/ Thread thread= new Thread(runnable);
Thread thread1= new Thread(runnable2);
thread.start();
thread1.start();
jedis.set("harry","veer");
System.out.println(jedis.get("harry"));
}
}
Here is what I am trying basically please help me with this
Related
Lets say i have a publisher app and it runs and publishes 20 messages and then goes down
import org.apache.pulsar.client.api.Producer;
import org.apache.pulsar.client.api.PulsarClient;
import org.apache.pulsar.client.api.PulsarClientException;
public class TestPub {
public static void main(String[] args) throws PulsarClientException, InterruptedException {
PulsarClient client = PulsarClient.builder()
.serviceUrl("pulsar://172.20.170.147:6650")
.build();
Producer<byte[]> producer = client.newProducer()
.topic("example-topic")
.create();
for (int i = 0; i < 20; i++)
{
String msg = ""+i;
producer.newMessage()
.value(msg.getBytes())
.send();
System.out.println("Sent:"+msg);
Thread.sleep(1000);
}
}
}
and then i have a subscriber app which can use either a consumer or reader but it starts after the publisher is done, i need it to read only the latest message published by publisher before i thought this code should do it but somehow it is not working, any clues folks?
import org.apache.pulsar.client.api.*;
public class TestSub {
public static void main(String[] args) throws PulsarClientException {
PulsarClient client = PulsarClient.builder()
.serviceUrl("pulsar://172.20.170.147:6650")
.build();
read(client);
consume(client);
}
static void consume(PulsarClient client) throws PulsarClientException {
Consumer consumer = client.newConsumer()
.topic("example-topic")
.subscriptionName("my-subscription-consumer")
.subscriptionType(SubscriptionType.Exclusive)
.subscriptionInitialPosition(SubscriptionInitialPosition.Latest)
.startMessageIdInclusive()
.subscribe();
//consumer.seek(MessageId.latest);
while (true) {
// Wait for a message
Message msg = consumer.receive();
try {
System.out.println("Message consumed: " +
new String(msg.getData()));
//consumer.acknowledge(msg);
} catch (Exception e) {
consumer.negativeAcknowledge(msg);
}
}
}
static void read(PulsarClient client) throws PulsarClientException {
Reader consumer = client.newReader()
.topic("example-topic")
.subscriptionName("my-subscription-reader")
.startMessageIdInclusive()
.startMessageId(MessageId.latest)
.create()
;
while (true) {
// Wait for a message
Message msg = consumer.readNext();
try {
System.out.println("Message read: " +
new String(msg.getData()));
//consumer.acknowledge(msg);
} catch (Exception e) {
System.out.println(e);
}
}
}
}
Based on the Pulsar API, Message.latest is "MessageId that represents the next message published in the topic." It is NOT the last message published to the topic, but rather the next one to be published. I can see where the naming of this enum could cause that confusion.
So in this scenario the expected behavior is for the readers/consumers to wait until another message is published to the topic before they are triggered to run.
Can someone please provide example code on how to use the Bluetooth cn1 library to read and write text data? I tried looking through the project source code (https://github.com/chen-fishbein/bluetoothle-codenameone) for example code, but could not find any that reads/writes text data using the appropriate methods. Those methods also don't have any Java docs.
Here's the code I'm using to send:
public void sendMessage(String message) {
if (Display.getInstance().isSimulator()) {
System.out.println(message);
} else {
// System.out.println("Sending message: " + message);
String b64WriteString = Base64.encode(message.getBytes());
try {
bt.write(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
}
}, deviceAddress, services.get(0), sendDataCharacteristic, b64WriteString, false);
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
And here to receive:
private void registerNotifications() {
System.out.print("Registering notifications...");
try {
bt.subscribe(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
JSONObject dataIncoming = (JSONObject) evt.getSource();
String base64Value = "";
try {
if (dataIncoming.getString("status").equals("subscribedResult")) {
base64Value = dataIncoming.getString("value");
}
} catch (JSONException e) {
e.printStackTrace();
}
String message = new String(Base64.decode(base64Value.getBytes()));
Display.getInstance().callSerially(new Runnable() {
#Override
public void run() {
messageReceived.set(message);
}
});
}
}, deviceAddress, services.get(0), receiveDataCharacteristic);
System.out.println("Registered");
System.out.println("Starting communication");
} catch (IOException e) {
System.err.println("Unable to register notifications " + e.getMessage());
e.printStackTrace();
}
}
I have fields defined for the service and characteristic UUID's. Also, the callSerially might not be needed anymore. I think I recall that the CN1LIB was updated to do that, but I don't remember for certain.
For that device, the service characteristic is "6E400001-B5A3-F393-E0A9-E50E24DCCA9E"
The sendCharacteristic is "0x0002"
The receiveCharacteristic is "0x0003"
After taking the suggestions of James H, and some more trial an error, I finally manage to get data transfer between the Adafruit's Bluefruit LE Friend working consistently, at least on an Android device. Not sure about iOS though, since I haven't tested it. Here are the critical code pieces needed.
First, you need the Service, TX and RX Characteristics UUIDs. These UUIDs were found here. Note, these don't need to be upper case.
public static final String UUID_SERVICE = "6e400001-b5a3-f393-e0a9-e50e24dcca9e";
public static final String UUID_RX = "6e400003-b5a3-f393-e0a9-e50e24dcca9e";
public static final String UUID_TX = "6e400002-b5a3-f393-e0a9-e50e24dcca9e";
Next, once you scanned and found the devices, call the connect() method to make the actual connection, and critically call the discover() method. Once the discover() callback gets called, then add the "subscriber" to receive data.
private void connect(String address) {
bleAddress = address; // set the global BLE address
if (!connected) {
// start an infinite progress dialog
final Dialog ip = new InfiniteProgress().showInifiniteBlocking();
try {
bt.connect(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
ip.dispose();
Object obj = evt.getSource();
print("Connected to Bluetooth LE device ...\n" + obj, true);
// must be called on Android devices in order to load on the UUIDs, otherwise there is an error that service can't be found. Won't do anything on ios though?
discover();
connected = true;
}
}, address);
} catch (IOException ex) {
ip.dispose();
String message = "Error connecting to bluetooth device: " + address;
print(message + "\n" + ex.getMessage(), false);
}
} else {
String message = "BLE device already connected to: " + address;
print(message, false);
}
}
private void discover() {
try {
bt.discover(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
print("BLE Information Received ...", true);
addSubscriber();
}
}, bleAddress);
} catch (Exception ex) {
print(ex.getMessage(), false);
}
// if we running on is add the subscriber here since the above bt call
// does nothing?
if (Display.getInstance().getPlatformName().equals("ios")) {
print("Adding subscriber for iOS Device", true);
addSubscriber();
}
}
private void addSubscriber() {
try {
bt.subscribe(new ActionListener() {
StringBuilder sb = new StringBuilder();
#Override
public void actionPerformed(ActionEvent evt) {
JSONObject dataIncoming = (JSONObject) evt.getSource();
String base64Value = "";
try {
if (dataIncoming.getString("status").equals("subscribedResult")) {
base64Value = dataIncoming.getString("value");
}
} catch (JSONException e) {
console.setText("Error reading data: " + e.getMessage());
}
String message = new String(Base64.decode(base64Value.getBytes()));
sb.append(message);
if (message.endsWith("\r\n")) {
processData(sb.toString());
sb = new StringBuilder();
}
}
}, bleAddress, UUID_SERVICE, UUID_RX);
String message = console.getText() + "\nSubcriber added ...";
console.setText(message);
} catch (IOException ex) {
String message = "Error Subscribing: " + ex.getMessage();
console.setText(message);
}
}
So this sets up the connection, discovers the services, and finally adds the subscriber method which receives the data, and critically uses a buffer to collect the received data until the CRLF characters are received.
However, another major issue I ran into was the default 23 byte send limit (maybe an Android only issue?) of the BLE specification. If you tried sending more than this, the connection just gets dropped with no meaningful error message being returned. To get around this, I used the technique suggested here, which entails splitting data into chunks of 20 byte arrays. Since we sending regular ASCII text, then 20 characters should be 20 bytes, so I just split the text into Strings 20 characters long. Not the most efficient by it works and it easier to debug.
private void sendText(final String data) {
try {
String b64String = Base64.encode(data.getBytes());
bt.write(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
if(data.endsWith("\r\n")) {
print("Data sent ...", true);
}
}
}, bleAddress, UUID_SERVICE, UUID_TX, b64String, false);
} catch (IOException ex) {
String message = "Error sending: " + data + "\n"
+ UUID_SERVICE + "\n"
+ UUID_TX + "\n"
+ ex.getMessage();
print(message, false);
}
}
private void splitAndSend(String text) {
text += "\r\n";
// first split data in chunk size of 20 chracters
ArrayList<String> sl = new ArrayList<>();
char[] data = text.toCharArray();
int len = data.length;
int chunkSize = 20;
for (int i=0; i < len; i+= chunkSize) {
sl.add(new String(data, i, Math.min(chunkSize,len - i)));
}
// now send chunks amd wait 100 ms to prevent any erros
for(String word: sl) {
sendText(word);
try {
Thread.sleep(100);
} catch (InterruptedException ex) {}
}
}
The complete source code with GUI stuff can be found here, but this is definitely a work in progress.
im writing a multithread chat program where i hope to have a server connected to multiple clients, the clients can talk to each and send messages to each other. I want all messages from the clients to be visible to the server, moreover that the server can send messages to all visible clients. My program only connects the server to one client and they can send messages.
package chatserver2;
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;
// import all the class that you will need for functionailty
// extends jframe to develop gui's in java
public class Server2 {
private static JTextField userInput; //
private static JTextArea theChatWindow; //
private static ObjectOutputStream output; // stream data out
private static ObjectInputStream input; // stream data in
private static ServerSocket server;
private static Socket connection; // socket means set up connetion between 2 computers
private static JFrame frame;
private static int n;
//Constructor
public static void main(String[] args) throws IOException {
Server2 obj = new Server2();
// Socket sock=new Socket("localhost",6789);
System.out.println("Hello 4");
obj.RunServer();
System.out.println("Hello 3");
try {
while (true) {
System.out.println("Hello 2");
Handler obj2 = new Handler();
//Handler obj3=new Handler();
obj2.start();
System.out.println("Accepted connection from "
+ connection.getInetAddress() + " at port "
+ connection.getPort());
n++;
System.out.println("Count " + n);
}
} finally {
connection.close();
}
}
public Server2() {
frame = new JFrame();
userInput = new JTextField();
userInput.setEditable(false); // set this false so you dont send messages when noone is available to chat
// action event listener to check when the user hits enter for example
userInput.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
sendMessage(event.getActionCommand()); // string entered in the textfield
userInput.setText(""); // reset text area to blank again
}
}
);
// create the chat window
frame.add(userInput, BorderLayout.NORTH);
theChatWindow = new JTextArea();
frame.add(new JScrollPane(theChatWindow));
frame.setSize(300, 150);
frame.setVisible(true);
}
// run the server after gui created
public void RunServer() {
try {
server = new ServerSocket(6789); // 1st number is port number where the application is located on the server, 2nd number is the amount of people aloud to connect
while (true) {
try {
waitForConnection(); // wait for a connection between 2 computers
setupStreams(); // set up a stream connection between 2 computers to communicate
whileChatting(); // send message to each other
// connect with someone and have a conversation
} catch (EOFException eofException) {
showMessage("\n Server ended Connection");
}
}
} catch (IOException ioException) {
ioException.printStackTrace();
}
}
//Wait for a connection then display connection information
private void waitForConnection() {
showMessage("waiting for someone to connect to chat room....\n");
try {
connection = server.accept();
} catch (IOException ioexception) {
ioexception.printStackTrace();
}
showMessage("Now connected to" + connection.getInetAddress().getHostName());
showMessage(" at port " + connection.getPort());
}
// stream function to send and recive data
private void setupStreams() throws IOException {
output = new ObjectOutputStream(connection.getOutputStream()); // set up pathway to send data out
output.flush(); // move data away from your machine
input = new ObjectInputStream(connection.getInputStream()); // set up pathway to allow data in
// String message = "WAIT";
// sendMessage(message);
//showMessage("\n Connection streams are now setup \n");
}
// this code while run during chat conversions
private void whileChatting() throws IOException {
String message = "WAIT ";
sendMessage(message);
allowTyping(true); // allow user to type when connection
do {
// have conversion while the client does not type end
try {
message = (String) input.readObject(); // stores input object message in a string variable
showMessage("\n " + message);
System.out.println("Message from Client " + message);
} catch (ClassNotFoundException classnotfoundException) {
showMessage("\n i dont not what the user has sent");
}
} while (!message.equals("CLIENT - END"));// if user types end program stops
}
private void closeChat() {
showMessage("\n closing connections...\n");
allowTyping(true);
try {
output.close(); // close output stream
input.close(); // close input stream
connection.close(); // close the main socket connection
} catch (IOException ioexception) {
ioexception.printStackTrace();
}
}
// send message to the client
private void sendMessage(String message) {
try {
output.writeObject(message);
output.flush(); // send all data out
showMessage("\nServer - " + message);
System.out.println("Message to client " + message);
} catch (IOException ioexception) {
theChatWindow.append("\n ERROR: Message cant send");
}
}
// update the chat window (GUI)
private void showMessage(final String text) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
theChatWindow.append(text);
}
}
);
}
// let the user type messages in their chat window
private void allowTyping(final boolean trueOrFalse) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
userInput.setEditable(trueOrFalse);
}
}
);
}
public static class Handler extends Thread {
private Socket connection;
// static private ServerSocket server;
public Handler() {
// this.socket = socket;
String message = "WAIT";
}
//connection = server.accept();
public void run() {
System.out.println("Connect" + Server2.connection);
while (true) {
try {
waitForConnection();
setupStreams();
whileChatting();
} catch (IOException ex) {
Logger.getLogger(Server2.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
private void waitForConnection() {
System.out.println("Heelo");
showMessage("waiting for someone to connect to chat room....\n");
System.out.println("server" + server);
try {
connection = server.accept();
} catch (IOException ioexception) {
ioexception.printStackTrace();
}
System.out.println("Connection" + connection);
showMessage("Now connected to" + connection.getInetAddress().getHostName());
showMessage("AT port" + connection.getPort());
}
private void setupStreams() throws IOException {
output = new ObjectOutputStream(connection.getOutputStream()); // set up pathway to send data out
output.flush(); // move data away from your machine
input = new ObjectInputStream(connection.getInputStream()); // set up pathway to allow data in
showMessage("\n Connection streams are now setup \n");
}
// this code while run during chat conversions
private void whileChatting() throws IOException {
String message = " You are now connected ";
sendMessage(message);
allowTyping(true); // allow user to type when connection
do {
// have conversion while the client does not type end
try {
message = (String) input.readObject(); // stores input object message in a string variable
showMessage("\n " + message);
} catch (ClassNotFoundException classnotfoundException) {
showMessage("\n i dont not what the user has sent");
}
} while (!message.equals("CLIENT - END"));// if user types end program stops
}
private void closeChat() {
showMessage("\n closing connections...\n");
allowTyping(true);
try {
output.close(); // close output stream
input.close(); // close input stream
connection.close(); // close the main socket connection
} catch (IOException ioexception) {
ioexception.printStackTrace();
}
}
// send message to the client
static private void sendMessage(String message) {
try {
output.writeObject(message);
output.flush(); // send all data out
showMessage("\nServer - " + message);
} catch (IOException ioexception) {
theChatWindow.append("\n ERROR: Message cant send");
}
}
// update the chat window (GUI)
static private void showMessage(final String text) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
theChatWindow.append(text);
}
}
);
}
// let the user type messages in their chat window
private void allowTyping(final boolean trueOrFalse) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
userInput.setEditable(trueOrFalse);
}
}
);
}
}
}
Here is the client :
package chatserver2;
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
// import all the class that you will need for functionailty
// extends jframe to develop gui's in java
public class Client2 extends JFrame {
private JTextField userInput; //
private JTextArea theChatWindow; //
private ObjectOutputStream output; // stream data out
private ObjectInputStream input; // stream data in
private Socket connection; // socket means set up connetion between 2 computers
//Constructor
public Client2() {
super("My Chat Service");
userInput = new JTextField();
userInput.setEditable(false); // set this false so you dont send messages when noone is available to chat
// action event listener to check when the user hits enter for example
userInput.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
sendMessage(event.getActionCommand()); // string entered in the textfield
userInput.setText(""); // reset text area to blank again
}
}
);
// create the chat window
add(userInput, BorderLayout.NORTH);
theChatWindow = new JTextArea();
add(new JScrollPane(theChatWindow));
setSize(300, 150);
setVisible(true);
}
// run the server after gui created
public void RunServer() {
try {
connection = new Socket("localhost", 6789);// 1st number is port number where the application is located on the server, 2nd number is the amount of people aloud to connect
while (true) {
try {
// wait for a connection between 2 computers
setupStreams(); // set up a stream connection between 2 computers to communicate
whileChatting(); // send message to each other
// connect with someone and have a conversation
} catch (EOFException eofException) {
showMessage("\n Server ended Connection");
} finally {
closeChat();
}
}
} catch (IOException ioException) {
ioException.printStackTrace();
}
}
//Wait for a connection then display connection information
// stream function to send and recive data
private void setupStreams() throws IOException {
output = new ObjectOutputStream(connection.getOutputStream()); // set up pathway to send data out
output.flush(); // move data away from your machine
input = new ObjectInputStream(connection.getInputStream()); // set up pathway to allow data in
showMessage("\n Connection streams are now setup \n");
}
// this code while run during chat conversions
private void whileChatting() throws IOException {
String message = "";
allowTyping(true); // allow user to type when connection
do {
// have conversion while the client does not type end
try {
message = (String) input.readObject(); // stores input object message in a string variable
System.out.println("message " + message);
if (message.equals("WAIT")) {
ServerSocket server2 = new ServerSocket(5000);
System.out.println("Hello");
message = "5000";
sendMessage(message);
}
System.out.println("From server " + message);
showMessage("\n " + message);
} catch (ClassNotFoundException classnotfoundException) {
showMessage("\n i dont not what the user has sent");
}
} while (!message.equals("CLIENT - END"));// if user types end program stops
}
private void closeChat() {
showMessage("\n closing connections...\n");
allowTyping(true);
try {
output.close(); // close output stream
input.close(); // close input stream
connection.close(); // close the main socket connection
} catch (IOException ioexception) {
ioexception.printStackTrace();
}
}
// send message to the client
private void sendMessage(String message) {
try {
output.writeObject(" - " + message);
output.flush(); // send all data out
showMessage("\nServer - " + message);
} catch (IOException ioexception) {
theChatWindow.append("\n ERROR: Message cant send");
}
}
// update the chat window (GUI)
private void showMessage(final String text) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
theChatWindow.append(text);
}
}
);
}
// let the user type messages in their chat window
private void allowTyping(final boolean trueOrFalse) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
userInput.setEditable(trueOrFalse);
}
}
);
}
public static void main(String[] args) {
Client2 obj = new Client2();
obj.RunServer();
}
}
I am currently working on Internet Of Things, in my current project I was Created the One Azure Cloud Service Project in that I Created the Worker Role, inside the worker role i have wrote below lines of code.
public class WorkerRole : RoleEntryPoint
{
private readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
private readonly ManualResetEvent runCompleteEvent = new ManualResetEvent(false);
private static string connectionString;
private static string eventHubName;
public static ServiceClient iotHubServiceClient { get; private set; }
public static EventHubClient eventHubClient { get; private set; }
public override void Run()
{
Trace.TraceInformation("EventsForwarding Run()...\n");
try
{
this.RunAsync(this.cancellationTokenSource.Token).Wait();
}
finally
{
this.runCompleteEvent.Set();
}
}
public override bool OnStart()
{
// Set the maximum number of concurrent connections
ServicePointManager.DefaultConnectionLimit = 12;
// For information on handling configuration changes
// see the MSDN topic at http://go.microsoft.com/fwlink/?LinkId=166357.
bool result = base.OnStart();
Trace.TraceInformation("EventsForwarding OnStart()...\n");
connectionString = ConfigurationManager.AppSettings["Microsoft.ServiceBus.ConnectionString"];
eventHubName = ConfigurationManager.AppSettings["Microsoft.ServiceBus.EventHubName"];
string storageAccountName = ConfigurationManager.AppSettings["AzureStorage.AccountName"];
string storageAccountKey = ConfigurationManager.AppSettings["AzureStorage.Key"];
string storageAccountString = string.Format("DefaultEndpointsProtocol=https;AccountName={0};AccountKey={1}",
storageAccountName, storageAccountKey);
string iotHubConnectionString = ConfigurationManager.AppSettings["AzureIoTHub.ConnectionString"];
iotHubServiceClient = ServiceClient.CreateFromConnectionString(iotHubConnectionString);
eventHubClient = EventHubClient.CreateFromConnectionString(connectionString, eventHubName);
var defaultConsumerGroup = eventHubClient.GetDefaultConsumerGroup();
string eventProcessorHostName = "SensorEventProcessor";
EventProcessorHost eventProcessorHost = new EventProcessorHost(eventProcessorHostName, eventHubName, defaultConsumerGroup.GroupName, connectionString, storageAccountString);
eventProcessorHost.RegisterEventProcessorAsync<SensorEventProcessor>().Wait();
Trace.TraceInformation("Receiving events...\n");
return result;
}
public override void OnStop()
{
Trace.TraceInformation("EventsForwarding is OnStop()...");
this.cancellationTokenSource.Cancel();
this.runCompleteEvent.WaitOne();
base.OnStop();
Trace.TraceInformation("EventsForwarding has stopped");
}
private async Task RunAsync(CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested)
{
//Trace.TraceInformation("EventsToCommmandsService running...\n");
await Task.Delay(1000);
}
}
}
Next I have wrote the below lines of code in SensorEventProcessor, for receiving the messages from event hub and send those messages to IoT hub.
class SensorEventProcessor : IEventProcessor
{
Stopwatch checkpointStopWatch;
PartitionContext partitionContext;
public async Task CloseAsync(PartitionContext context, CloseReason reason)
{
Trace.TraceInformation(string.Format("EventProcessor Shuting Down. Partition '{0}', Reason: '{1}'.", this.partitionContext.Lease.PartitionId, reason.ToString()));
if (reason == CloseReason.Shutdown)
{
await context.CheckpointAsync();
}
}
public Task OpenAsync(PartitionContext context)
{
Trace.TraceInformation(string.Format("Initializing EventProcessor: Partition: '{0}', Offset: '{1}'", context.Lease.PartitionId, context.Lease.Offset));
this.partitionContext = context;
this.checkpointStopWatch = new Stopwatch();
this.checkpointStopWatch.Start();
return Task.FromResult<object>(null);
}
public async Task ProcessEventsAsync(PartitionContext context, IEnumerable<EventData> messages)
{
Trace.TraceInformation("\n");
Trace.TraceInformation("........ProcessEventsAsync........");
//string commandParameterNew = "{\"Name\":\"AlarmThreshold\",\"Parameters\":{\"SensorId\":\"" + "Hello World" + "\"}}";
//await WorkerRole.iotHubServiceClient.SendAsync("astranidevice", new Microsoft.Azure.Devices.Message(Encoding.UTF8.GetBytes(commandParameterNew)));
foreach (EventData eventData in messages)
{
try
{
string jsonString = Encoding.UTF8.GetString(eventData.GetBytes());
Trace.TraceInformation(string.Format("Message received at '{0}'. Partition: '{1}'",
eventData.EnqueuedTimeUtc.ToLocalTime(), this.partitionContext.Lease.PartitionId));
Trace.TraceInformation(string.Format("-->Raw Data: '{0}'", jsonString));
SimpleTemperatureAlertData newSensorEvent = this.DeserializeEventData(jsonString);
Trace.TraceInformation(string.Format("-->Serialized Data: '{0}', '{1}', '{2}', '{3}', '{4}'",
newSensorEvent.Time, newSensorEvent.RoomTemp, newSensorEvent.RoomPressure, newSensorEvent.RoomAlt, newSensorEvent.DeviceId));
// Issuing alarm to device.
string commandParameterNew = "{\"Name\":\"AlarmThreshold\",\"Parameters\":{\"SensorId\":\"" + "Hello World" + "\"}}";
Trace.TraceInformation("Issuing alarm to device: '{0}', from sensor: '{1}'", newSensorEvent.DeviceId, newSensorEvent.RoomTemp);
Trace.TraceInformation("New Command Parameter: '{0}'", commandParameterNew);
await WorkerRole.iotHubServiceClient.SendAsync(newSensorEvent.DeviceId, new Microsoft.Azure.Devices.Message(Encoding.UTF8.GetBytes(commandParameterNew)));
}
catch (Exception ex)
{
Trace.TraceInformation("Error in ProssEventsAsync -- {0}\n", ex.Message);
}
}
await context.CheckpointAsync();
}
private SimpleTemperatureAlertData DeserializeEventData(string eventDataString)
{
return JsonConvert.DeserializeObject<SimpleTemperatureAlertData>(eventDataString);
}
}
When I was debug my code, the ProcessEventsAsync(PartitionContext context, IEnumerable messages) method will never call and just enter into OpenAsync() method then itstop the debugging.
Please tell me Where I did mistake in my project and tell me when the ProcessEventsAsync() method will call.
Regards,
Pradeep
IEventProcessor.ProcessEventsAsync is invoked when there are any unprocessed messages in the EventHub.
An Event Hub contains multiple partitions. A partition is an ordered sequence of events. Within a partition, each event includes an offset. This offset is used by consumers (IEventProcessor) to show the location in the event sequence for a given partition. When an IEventProcessor connects (EventProcessorHost.RegisterEventProcessorAsync), it passes this offset to the Event Hub to specify the location at which to start reading. When there are unprocessed messages (events with higher offset), they are delivered to the IEventProcessor. Checkpointing is used to persist the offset of processed messages (PartitionContext.CheckpointAsync).
You can find detailed information about the internals of EventHub: Azure Event Hubs overview
Have you sent any messages to the EventHub (EventHubClient.SendAsync(EventData))?
I am having trouble coding the socket side of a JavaFX chat client. This is my first time having to deal with socket in any sort of way, so some trouble was expected. I've been following this page to design the server-client side:
http://pirate.shu.edu/~wachsmut/Teaching/CSAS2214/Virtual/Lectures/chat-client-server.html
My problem is getting text I enter into the GUI into a DataInputSteam and DataOutputStream so that others on the same server can see the changes. I do
not understand how to convert the text in the UI to something the sockets
can work with.
Here is part of my controller class:
#FXML
private TextArea messageArea;
#FXML
private Button sendButton;
private ChatClient client;
#FXML
public void initialize() {
client = new ChatClient(ChatServer.HOSTNAME, ChatServer.PORT);
sendButton.setOnAction(event -> {
client.handle(messageArea.getText());
});
}
The ChatClient class is a Runnable with a DataInputStream and DataOutputStream field that connects to a Socket. I haven't changed much from the link:
public class ChatClient implements Runnable {
private Socket socket;
private Thread thread;
private DataInputStream streamIn;
private DataOutputStream streamOut;
private ChatClientThread client;
public ChatClient(String serverName, int port) {
System.out.println("Establishing connection...");
try {
socket = new Socket(serverName, port);
System.out.println("Connected: " + socket);
start();
} catch (UnknownHostException e) {
System.out.println("Unknown host: " + e.getMessage());
} catch (IOException e) {
System.out.println("Unexpected: " + e.getMessage());
}
}
#Override
public void run() {
while (thread != null) {
try {
streamOut.writeUTF(streamIn.readUTF());
streamOut.flush();
} catch (IOException e) {
System.out.println("Sending error: " + e.getMessage());
stop();
}
}
}
public void handle(String msg) {
try {
streamOut.writeUTF(msg);
streamOut.flush();
} catch (IOException e) {
System.out.println("Could not handle message: " + e.getMessage());
}
System.out.println(msg);
}
public void start() throws IOException {
streamIn = new DataInputStream(socket.getInputStream());
streamOut = new DataOutputStream(socket.getOutputStream());
if (thread == null) {
client = new ChatClientThread(this, socket);
thread = new Thread(this);
thread.start();
}
}
So in the controller class, I am calling the handle method which deals with the streams. The original code just wrote to the console, so I had to change the line:
streamIn = new DataInputStream(System.in)
to
streamIn = new DataInputStream(socket.getInputStream());
There is also a ChatClientThread class that extends Thread and just calls ChatClient.handle() in its run method.
I guess my question is how to update a GUI whenever writeUTF and readUTF interact with the DataStreams. I understand that streamOut.writeUTF(msg) changes the DataOutputStream to "have" that string, but I'm not sure how I'm supposed to use that datastream to update my gui so that all clients using the application can see the update. The way I have it now, if I run two instances of the JavaFX app, they dont' communicate through the UI or the console. My program just stalls whenever I click the send button