I have modified the example shown on https://code.google.com/p/java-simple-serial-connector/wiki/jSSC_examples to show read/write from java program. I can run the program, however the data I send using serialPort.writeString("HelloWorld"); does not seem to be read in the SerialPortReader event class. Could any one please point what the issue is ?
public class SerialReaderWriter {
static SerialPort serialPort;
public static void main(String[] args) {
serialPort = new SerialPort("COM1");
try {
serialPort.openPort();
serialPort.setParams(9600, 8, 1, 0);
//Preparing a mask. In a mask, we need to specify the types of events that we want to track.
//Well, for example, we need to know what came some data, thus in the mask must have the
//following value: MASK_RXCHAR. If we, for example, still need to know about changes in states
//of lines CTS and DSR, the mask has to look like this: SerialPort.MASK_RXCHAR + SerialPort.MASK_CTS + SerialPort.MASK_DSR
int mask = SerialPort.MASK_RXCHAR;
//Set the prepared mask
serialPort.setEventsMask(mask);
//Add an interface through which we will receive information about events
serialPort.addEventListener(new SerialPortReader());
serialPort.writeString("HelloWorld");
}
catch (SerialPortException ex) {
System.out.println(ex);
}
}
static class SerialPortReader implements SerialPortEventListener {
public void serialEvent(SerialPortEvent event) {
//Object type SerialPortEvent carries information about which event occurred and a value.
//For example, if the data came a method event.getEventValue() returns us the number of bytes in the input buffer.
System.out.println(event.getEventType());
if(event.isRXCHAR()){
if(event.getEventValue() == 10){
try {
String data= serialPort.readString();
System.out.println(data);
}
catch (SerialPortException ex) {
System.out.println(ex);
}
}
}
//If the CTS line status has changed, then the method event.getEventValue() returns 1 if the line is ON and 0 if it is OFF.
else if(event.isCTS()){
if(event.getEventValue() == 1){
System.out.println("CTS - ON");
}
else {
System.out.println("CTS - OFF");
}
}
else if(event.isDSR()){
if(event.getEventValue() == 1){
System.out.println("DSR - ON");
}
else {
System.out.println("DSR - OFF");
}
}
}
}
}
You can't read data from the same port where you write(COM1 here). I have followed the below steps for reading and writing using JSSC.
Fake your serial port with SerialPortMonitor.
Send data from COM2 from the SerialPortMonitor device installed.
Mode->Spy would show your written string "HelloWorld" and received String "OK"
Make the below modifications and check your code:
serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_RTSCTS_IN |
SerialPort.FLOWCONTROL_RTSCTS_OUT);
serialPort.writeBytes("HelloWorld");//Write data to port
PortReader portReader=new PortReader(serialPort)
serialPort.addEventListener(portReader, SerialPort.MASK_RXCHAR);
int[][] eventArray=serialPort.waitEvents()
for (int i = 0; i < eventArray.length; i++) {
if ((eventArray[i][0] > 0) ) {
serialPort.eventListener.serialEvent(new SerialPortEvent("COM1", eventArray[i][0], eventArray[i][1])); // wait for the listener event to complete
}
}
The port reader class: (You were missing the Override annotation and passing in the serial port)
public class PortReader implements SerialPortEventListener{
SerialPort serialPort
public PortReader(){}
public PortReader(SerialPort serialPort){this.serialPort=serialPort}
#Override
public void serialEvent(SerialPortEvent event) {
if(event.isRXCHAR() && event.getEventValue() > 0) {
try {
String receivedData = this.serialPort.readString(event.getEventValue());
System.out.println("Received response: " + receivedData);
this.serialPort.closePort();//Close serial port
}
catch (SerialPortException ex) {
System.out.println("Error in receiving string from COM-port: " + ex);
this.serialPort.closePort();//Close serial port
}
}
}
}
The command
serialPort.writeString("HelloWorld");
sends the string
HelloWorld
from COM1. The SerialPortReader class that you are implementing causes COM1 to listen for the event type isRXCHAR (AKA when COM1 receives a char).
Do you have a serial cable connected to the serial port?
Unless you cross the RX and TX pins of COM1 or have a separate COM port (whose TX and RX is connected to COM1's RX and TX pins respectively), the SerialPortReader will never be activated.
if your device doesn't require RTS/CTS flow control
or you dont have a fully connected serial cable
( only RX, TX, GND)
you should switch off the data terminal ready (dtr)
signal for the serial communication
add this
serialPort.setRTS(false);
serialPort.setDTR(false);
after
serialPort.addEventListener(new SerialPortReader());
Related
I modified an open-source project on github for a school project to fit my needs
it had a broadcast() method to send messages and it was called in the run() method in a while loop but the problem is that broadcast() sends a message to all users in a userList<>i wanted to add the ability to send a private message to one of the users by writing #username.
Here is the code for broadcast method:
private synchronized void broadcast(String msg) {
for (int i = 0; i < clientList.size(); i++) {
clientList.get(i).write(msg);
}
System.out.println("Log: Message broadcast --> " + msg);
}
and here is the run() method
public void run() {
System.out.println("Log: Got input/output streams for connected client.");
/** Get the first message from the client, attempt communication */
String clientMsg = null;
boolean accepted = false;
/** Allow client to create an account, login, or quit */
do {
clientMsg = client.read();
if (clientMsg.equals("QUIT")) {
System.out.println("Log: Client disconnected without signing in.");
client.disconnect();
return;
}
else if (clientMsg.startsWith("NEWUSER: ")) {
createUser(clientMsg);
}
else if (clientMsg.startsWith("LOGIN: ")) {
accepted = authenticate(clientMsg);
}
else
{
System.out.println("Log: Unexpected client message -> " + clientMsg);
client.disconnect();
return;
}
} while(!accepted);
/** Run main chat loop. Will read from the client, and broadcast each read
* until the client disconnects. */
while (true) {
int i=0;
String username= clientList.get(i).getUsername();
String line = client.read();
if (line == null) break;
else if(line.startsWith("#"+username)){
broadcastp(line,username);
}
else {
broadcast(line);
}
i++;
}
/** The only way for the client to exit the above loop is to disconnect.
* Therefore, call the handler's exit routine */
exit();
}
Here is the broadcastp() method that i tried to implement this feature with, but it doesn't work. It compiles and runs perfectly though just without the private chat feature.
private synchronized void broadcastp(String msg,String username) {
for (int i = 0; i < clientList.size(); i++) {
username = clientList.get(i).getUsername();
if(msg.startsWith("#"+username))
{clientList.get(i).write(msg);}
else {
continue;
}}
System.out.println("Log: Message broadcast --> " + msg);}
I do not have the full picture of how your program works, but you say the program runs perfectly, but does not do the private messaging part.
If I look at your code, in the while loop you always take the first username from the clientList (i = 0) and only call broadcastp if the line starts with that name.
First of all.. is broadcastp ever invoked? In broadcastp you have another loop, but that will always match on i == 0 given the way you invoke it (with the line and username from the while loop).
The problem seems to be be there. So something like this within the while loop might work for you (remove the i variable, and no need for broadcastp):
boolean isPrivate = false;
String line = client.read();
for (User user : clientList) {
if (line.startsWith("#" + user.getUsername())) {
user.write(line);
isPrivate = true;
break;
}
}
if (!isPrivate) {
broadcast(line);
}
I am trying to create a messenger program and have successfully set up client-server connections using sockets. However I am finding it difficult to code the process of having several clients communicating simultaneously. Shown in the code below is the methods for the chats that are held within a ClientThread class that regulates the interaction between client and server using threads stored in a shared ArrayList. How would you implement the code for multiple peer-to-peer chats here?
startChat method:
public void startChat()
{
// start the convo!
// first of all the user chooses who to speak to
// starts a loop until user enters a valid username or 'Group'
String line = "";
boolean validCommand = false;
while(validCommand == false)
{
try {
line = in.readLine();
} catch (IOException e) {
System.out.println("Problem reading reply about user chat");
}
if(line.equalsIgnoreCase("Group"))
{
validCommand = true;
chatAll(); // an integer of negative one starts a chat with everyone
}
else
{
synchronized(this){
// find user
for(int i = 0; i < threads.size(); i++)
{
if(threads.get(i) != null && threads.get(i).username != null)
{
if(threads.get(i).username.equals(line)) // means that we have found the index of the thread that the client wants to speak to
{
/*// START : BETWEEN THESE CAPITALISED COMMENTS IS MY ATTEMPT TO INITIATE TWO WAY CHAT
int thisIndex = -1;
for(int j = 0; j < threads.size(); j++) // gets the index of this thread object in the array
{
if(threads.get(j) == this)
{
thisIndex = j;
// out.println(j);
}
}
if(thisIndex != -1)
{
threads.get(i).out.println(username + " is trying to connect");
threads.get(i).processChat(thisIndex); // this is the line causing the problem!
}
// END : BETWEEN THESE CAPITALISED COMMENTS IS MY ATTEMPT TO INITIATE TWO WAY CHAT */
threads.get(i).out.println(username + " is trying to connect");
out.println("Chat with " + threads.get(i).username);
processChat(i);
validCommand = true;
}
// if the command is not group and not a username, it is not valid and we ask the user to re-enter
else if(i == threads.size() - 1)
{
out.println("This command is not valid, please re-enter");
}
}
}
} // end of synchronised bit
} // end of else statement
} // end of while loop
}
allChat method:
void chatAll()
//for the purpose of group chat
{
out.println("Group chat initiated");
boolean d = true;
while(d == true)
{
String message = "";
try {
message = in.readLine();
} catch (IOException e) {
System.out.println("Can't read line from client");
}
if(message.contains("goodbye") == true)
{
d = false;
}
else
{
synchronized(this)
{
for(int j = 0; j < threads.size(); j++)
{
if(threads.get(j) != null)
{
threads.get(j).out.println(username + ": " + message);
}
}
}
}
}
}
processChat method:
void processChat(int i)
//for the purpose of talking to pre-defined user
{
boolean d = true;
while(d == true)
{
String message = "";
try {
message = in.readLine();
} catch (IOException e) {
System.out.println("Can't read message from client");
}
if(message.contains("goodbye") == true)
{
d = false;
}
else {
if(threads.get(i) != null)
{
threads.get(i).out.println(username + ": " + message);
}
}
}
}
Just for good measure and a reference here is the overall client class (confusingly labelled ThreadedClient as opposed to ClientThread haha)
ThreadedClient class:
import java.net.*;
import java.io.*;
public class ThreadedClient implements Runnable {
// client socket
private static Socket clientSocket = null;
//I/O streams to and from the server
private static BufferedReader in = null;
private static PrintStream out = null;
// Input stream to read user input
private static BufferedReader inputReader = null;
private boolean open = true;
public ThreadedClient(String host, int port)
{
startConnection(host, port);
}
public void startConnection(String host, int port)
{
//open up the socket
try {
clientSocket = new Socket(host, port);
} catch (UnknownHostException e) {
System.out.println("The host name '" + host + "' isn't known");
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("Cannot create socket");
}
// connect I/O streams
try {
in = new BufferedReader(new InputStreamReader(new DataInputStream(clientSocket.getInputStream())));
out = new PrintStream(clientSocket.getOutputStream());
inputReader = new BufferedReader(new InputStreamReader(System.in));
} catch (IOException e) {
System.out.println("Problem connecting streams");
}
// process the chat itself
// the thread deals with input coming in
Thread thread = new Thread(this);
thread.start();
// the loop deals with output
while(open == true)
{
String message;
try {
message = inputReader.readLine();
out.println(message);
if(message.contains("goodbye") == true)
{
open = false;
}
} catch (IOException e) {
System.out.println("Problem sending messages");
}
}
// chat is done, so we can close resources
try {
in.close();
inputReader.close();
out.close();
clientSocket.close();
} catch (IOException e) {
System.out.println("Problem closing resources");
}
}
// run method for sending input out. I imagine this will not be necessary in the GUI implemented version, as we can use
// an action listener for the send function, e.g. one that reads a text field into a output stream everytime the user clicks enter
public void run() {
while(open == true)
{
try {
String response = in.readLine();
if(response.contains("goodbye") == true)
{
open = false;
}
System.out.println(response);
} catch (IOException e) {
System.out.println("Problem recieving messages");
}
}
}
public static void main(String[] args)
{
ThreadedClient socket = new ThreadedClient("localhost", 50000);
}
}
I know that this code may not be as advanced as some others I have seen on this forum as well as DreamInCode and others but I was trying to build it from scratch and have been stuck here for what feels like a millennia. Trawling through the internet has not helped :(
Any suggestions and criticisms would be an absolute God send!
Thanks in advance guys.
OK.
You can do like this: Im focus on Console Application
- Define a class call Message:
class Message
{
public String username; // the sender that send this message to u.So you can reply back to this user
public boolean groupMessage; // this message is group message or not
public String message;
}
Define a global variable: ArrayList messages; to hold all incomming messages.
So when you start chat with a client --> create new Thread to read message from him.When you receive a message . You have to put that message to the array list: messages ( you have to remember to sync it. because it will be invoked by many thread)
synchorized(messages){
messages.add(....); // new message here
}
Then , you create a new Thread to show message & can reply back to the sender. In this read you will pop a message from array list messages & show it.
while(isrunning)
{
synchorized(messages){
if(messages.size()<=0) messages.wait(); // when you receive a new message you have to notify
}
synchorized(messages){
Message msg = messages.get(0);
messages.remove(0);
showmessage_to_ouput(msg); // something like this.
String s = read from input // to reply to this message.
Reply(....)// here you can check if this message is group message--> reply to all,..etc
}
}
P/S: That's a idea :) good luck
I can give you a solution , but you have to implement it
We have:
- Server A, Client B & C. B & C already connected to Server via TCP connection
- The first, client B want to chat with C. So B have to send a message by UDP to server
- 2nd, Server will receive a UDP messages from B ==> Server know which ip & port of B that B connected to Server by UDP. Then server send to C a message (TCP) that contains info about UDP ip:port of B .
- 3rd: Client C will receive that message from server via TCP . So C know ip:port that B is listenning .--> If C accept chat with B . C have to send a UDP message to Server to tell server that C accept to talk with B.
- 4th: Server will receive that message via UDP . So Server also know ip:port of C in UDP.
- 5th : The server will transfer UDP ip:port of C to B via TCP (or UDP if you want).
- 6th: Client B will receive it & know udp ip:port of C. So they can start to chat via UDP protocol now.
IT is call UDP/TCP Hole punching. You can research more about it to implement.
P/S: But this method doesnt work with Symetric NAT
I need a help I'm trying to make client server app for copying files in java... I've got MainWnd object which creates TCPServer object and on send button it will create TCPClient object which send initial data to opponent TCPServer and will open given number of Listen Thread (let it be n) (this Listen threads are here only because they accept a file) (every thread listen on different port which send back to TCPClient) TCPClient then creates n other TCPClients threads which send the file... This I've got and it's running. Problem is, that file receiving can be interrupted by receiver when he click on button Interrupt. I can't get information of this interruption to the receiver's TCPServer thread, which should kill this n threads which are downloading the file.
I think the problem is in TCPServer, where is infinit loop, but the Socket in this will cause blocking of loop so I can't enter to Connection class and kill this n threads.
TCP SERVER
public void setSendInterruption() {
this.interruptedSending = true;
//c.setSendInterruption();
}
public TCPServer(int port, int socketNums, Map<Byte, LinkedList<Byte>> realData, File file, int fileLength) {
this.serverPort = port;
this.socketNums = socketNums;
if(file != null)
this.file = file;
if(fileLength != -1)
this.fileLength = fileLength;
if(realData != null)
this.realData = realData;
if(tmpData != null)
this.tmpData = tmpData;
}
#Override
public void run() {
try {
System.out.println(this.getId());
listenSocket = new ServerSocket(serverPort);
System.out.println("server start listening... ... ...");
while(true) {
if(interruptedSending)
System.out.println("Here I never come");
Socket clientSocket = listenSocket.accept();
Connection c = new Connection(clientSocket, socketNums, realData, file, fileLength);
}
}
catch(IOException e) {
System.out.println("Listen :"+e.getMessage());}
}
Connection
while (true)
{
byteRead = input.read();
//Thread.sleep(100);
if(interruptedSending) {
TCPClient tcpClient = new TCPClient(clientSocket.getPort(), clientSocket.getInetAddress().getHostAddress());
tcpClient.sendInterruptedData();
interruptedSending = false;
}
char lowChar;
if(byteRead == -1) {
break;
} else
lowChar = (char)byteRead;
lowData += lowChar;
if(lowData.length() >= 2) {
if (lowData.substring(lowData.length()-2).compareTo("//") == 0) {
break;
} else if (lowData.length() > 6) {
byteData.add((byte)byteRead);
}
}
}
In connection there is more lines, but they are only mainly parsing a protocol.
Thanks a lof for your help. I hope I wrote it clean...
From what I understand each Connection has a Thread that runs it. You want to interrupt each of these threads but can't do that from within the threads because they are stuck in input.read().
If that is what you meant, just do this:
In the constructor of Connection save the Thread, so you can access it later.
Make a killThread()-Method or therelike, so you can access the thread from the outside:
public void killThread() {
thread.interrupt(); //thread is the thread you saved in the constructor
}
When you want to kill the Connection-thread call killThread(). This will cause the Thread to throw a java.lang.InterruptedException, wherever it is at the moment.
This one you can either ignore (since you want the thread to die anyways) or you encase the whole while-loop with a
try {
//your loop
} catch (InterruptedException e) {
return;
}
which will end the thread nicely without throwing the exception out.
I'm trying to get some values from rs232 (card reader Roger prt66lt) with a java simple serial connetor (jssc) but it look like i dont get any events started. I'm using the example code. The card reader is set to send card number when he reads it. But i dont get any event started coz i dont see event that System.out. I'm including jssc.jar (from 2.5.0 version) and its connecting to divice. Is this version of jssc doesnt need any .dll ? I think its included in it ? The similar code to this one but with RXTX library works fine but i need to include attahed dll library.
Card reader send me HEX value: 02, 10 chars DATA, 0D, 0A, 03
Code:
import jssc.SerialPort;
import jssc.SerialPortEvent;
import jssc.SerialPortEventListener;
import jssc.SerialPortException;
public class Main {
static SerialPort serialPort;
public static void main(String[] args) {
serialPort = new SerialPort("COM4");
try {
serialPort.openPort();//Open port
serialPort.setParams(9600, 8, 1, 0);//Set params
int mask = SerialPort.MASK_RXCHAR + SerialPort.MASK_CTS + SerialPort.MASK_DSR;//Prepare mask
serialPort.setEventsMask(mask);//Set mask
serialPort.addEventListener(new SerialPortReader());//Add SerialPortEventListener
}
catch (SerialPortException ex) {
System.out.println(ex);
}
}
static class SerialPortReader implements SerialPortEventListener {
public void serialEvent(SerialPortEvent event) {
System.out.println("Event started");
if(event.isRXCHAR()){//If data is available
if(event.getEventValue() == 10){//Check bytes count in the input buffer
//Read data, if 10 bytes available
try {
byte buffer[] = serialPort.readBytes(10);
}
catch (SerialPortException ex) {
System.out.println(ex);
}
}
}
else if(event.isCTS()){//If CTS line has changed state
if(event.getEventValue() == 1){//If line is ON
System.out.println("CTS - ON");
}
else {
System.out.println("CTS - OFF");
}
}
else if(event.isDSR()){///If DSR line has changed state
if(event.getEventValue() == 1){//If line is ON
System.out.println("DSR - ON");
}
else {
System.out.println("DSR - OFF");
}
}
}
}
}
The problem was that the default setting of RTS and DTR line is High so i need to use another setParams method and set the RTS line to false as needed by device.
Solution:
serialPort.setParams(9600, 8, 1, 0, false, true);
I'm making a simple chat server and just made it so each connection runs on a new thread.
The old version started a single thread for the server, it did a while loop, which would stop when a stop message was sent then close the socket.
The new version loops forever and create a new thread for each new connection. Now I cannot close the socket connection.
If you press a key and the main thread stops, the socket stays open. Thus when I run the program again I need to change the socket number.
code of server
while(true)
{
///////////////////////////////////////////////////
// get a new connection
///////////////////////////////////////////////////
System.out.println("Aceepting connections on port 1030 \r");
try{
// Get New Connection
// wait for ever on accepting new connections
server.setSoTimeout(0);
connection=server.accept();
cConnection thread = new cConnection("thread3", connection);
} catch(IOException ec)
{
System.out.println(ec.getMessage());
}
}
code that starts server
Now each message comes in on a new thread, so I cannot tell it to stop and close the socket.
You need to provide a flag that must be globally accesible, so when some client wants to stop the server then change the variable ans stops the bucle. By example:
class YourServer {
private static boolean execute = true;
public static synchronized void stop() {
execute = false;
}
public void yourMethod() {
while(execute) {
// implement your server here
}
}
}
When a client send the command STOP you must be do
YourServer.stop();
If you want a stop command to stop the server you can call System.exit() to force the program to store or just closing server is likely to be all you need.
Looking into your problem, I understood one thing, that since you are putting
while (true), so your control always gets stuck at connection=server.accept(); listening for a new connection. So in order to stop the sockets you need to first find a way to stop looping in that while loop. Either you can set a Variable, like (int clientsConnected) to check the number of Clients, when that comes to zero stop that while loop. So you can stop your sockets.
Below is my sample code for clients which is doing the same thing for closing the Sockets.
Hopefully this solves your problem.
class GetNamesFromServer implements Runnable
{
private Socket sForName, sForId;
private BufferedReader in, inForName, inForId;
private PrintWriter outForName, outForId;
private static String clientNames;
public GetNamesFromServer(Socket s1, Socket s2)
{
sForName = s1;
sForId = s2;
}
public void run()
{
try
{
outForName = new PrintWriter(sForName.getOutputStream(), true);
outForName.println(Client.clientName);
System.out.println("Send Name : " + Client.clientName);
outForName.flush();
}
catch(IOException e)
{
System.err.println("Error sending Name to the Server.");
}
try
{
inForId = new BufferedReader(new InputStreamReader(sForId.getInputStream()));
Client.clientId = (inForId.readLine()).trim();
System.out.println("Client ID is : " + Client.clientId);
}
catch(IOException e)
{
System.err.println("Error Receiving ID from Server.");
}
try
{
inForName = new BufferedReader(new InputStreamReader(sForName.getInputStream()));
while (true)
{
clientNames = inForName.readLine();
if (clientNames != null && clientNames != "")
{
clientNames = clientNames.substring(1, clientNames.length() - 1);
System.out.println("Names Received : " + clientNames);
String[] names = clientNames.split(", ");
Client.nameClients.clear();
for (String element: names)
Client.nameClients.add(element);
Client.nPane.setText("");
int size = Client.nameClients.size();
System.out.println("Size of list : " + size);
for (int i = 0; i < size; i++)
{
String name = Client.nameClients.get(i);
String colour = Character.toString(name.charAt(0));
name = name.substring(1, name.length()) + "\n";
appendToNamePane(name, ReceiveMessages.getColour(Integer.parseInt(colour)), "Lucida Console");
}
System.out.println("Clients Online : " + Client.nameClients);
}
int index = Client.nameClients.indexOf(Client.clientId + Client.clientName);
**if (index == -1)
{
sForName.close();
break;
}**
}
}
catch(IOException e)
{
System.err.println("Error Receiving Names of Clients from Server");
}
}
NEW EDITION :
You can add a cap to maximum number of clients that can connect, once that reaches your while loop will not go to connection = server.accept(); and hence when they are done chatting (after some time) i.e. totalClients = 0, you can stop your sockets as well, to stop the program.
if (totalClients == 0)
{
socket.close();
serverSocket.close();
}
Regards