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Simple Client-Server program using Swing GUI

I'm making a simple, no thread Client-Server program where GUI has one button on both server and client side. When client presses button it changes text on a button to "C" and sends to server "C" string, so the button on the server side changes text to "C". Server works similarly to client but sends "S" instead of "C". They work in turns: when it's the client's turn, server's button is locked and he cannot change his button. Client always starts first.
When client presses button it works fine, but when server presses button it changes button to "S" on the server side but not on client's side. I know what I'm doing wrong.
Server code:
public class Serv implements ActionListener
{
private JButton button;
private boolean myTurn;
private ServerSocket sock;
private Socket s;
private BufferedReader input;
private PrintStream output;
public Serv() throws UnknownHostException, IOException
{
button = new JButton();
myTurn = false;
sock = new ServerSocket(9001);
s = null;
button = new JButton();
}
public void createGUI()
{
JFrame frame = new JFrame("TicTacToe - Server");
JPanel mainPanel = new JPanel();
mainPanel.setPreferredSize(new Dimension(100, 100));
button = new JButton("");
button.setPreferredSize(new Dimension(100, 100));
button.setFont(new Font(button.getFont().getName(), button.getFont().getStyle(), 70));
button.setActionCommand("1");
button.addActionListener(this);
mainPanel.add(button);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public void startMyGame() throws IOException
{
createGUI();
s = sock.accept();
input = new BufferedReader(new InputStreamReader(s.getInputStream()));
output = new PrintStream(s.getOutputStream(), true);
while(true)
{
if(myTurn == false)
{
myTurn = true;
String out = input.readLine();
button.setText(out);
}
}
}
public static void main(String args[])
{
Serv tc = null;
try
{
tc = new Serv();
tc.startMyGame();
}
catch(Exception ex)
{
ex.printStackTrace();
}
finally
{
try
{
tc.close();
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
private void close() throws IOException
{
this.sock.close();
this.input.close();
this.output.close();
}
#Override
public void actionPerformed(ActionEvent e)
{
if(myTurn == true)
{
if(e.getActionCommand().equals("1"))
{
JButton b = (JButton) e.getSource();
b.setText("S");
output.println("S");
myTurn = false;
}
}
}
}
Client code:
public class Cli implements ActionListener
{
private JButton button;
private boolean myTurn;
private Socket sock;
private BufferedReader input;
private PrintStream output;
public Cli() throws UnknownHostException, IOException
{
button = new JButton();
myTurn = true;
sock = new Socket("127.0.0.1", 9001);
input = new BufferedReader(new InputStreamReader(sock.getInputStream()));
output = new PrintStream(sock.getOutputStream(), true);
}
public void createGUI()
{
JFrame frame = new JFrame("TicTacToe - Client");
JPanel mainPanel = new JPanel();
mainPanel.setPreferredSize(new Dimension(100, 100));
button = new JButton("");
button.setPreferredSize(new Dimension(100, 100));
button.setFont(new Font(button.getFont().getName(), button.getFont().getStyle(), 70));
button.setActionCommand("1");
button.addActionListener(this);
mainPanel.add(button);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public void startMyGame() throws IOException
{
createGUI();
while(true)
{
if(myTurn == false)
{
myTurn = true;
String out = input.readLine();
button.setText(out);
}
}
}
private void close() throws IOException
{
this.sock.close();
this.input.close();
this.output.close();
}
public static void main(String args[])
{
Cli tc = null;
try
{
tc = new Cli();
tc.startMyGame();
}
catch(Exception ex)
{
ex.printStackTrace();
}
finally
{
try
{
tc.close();
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
#Override
public void actionPerformed(ActionEvent e)
{
if(myTurn == true)
{
if(e.getActionCommand().equals("1"))
{
JButton b = (JButton) e.getSource();
if(!b.getText().equals("X") || !b.getText().equals("O"))
{
b.setText("C");
output.println("C");
myTurn = false;
}
}
}
}
}
I have deleted imports so the codes would be shorter.

Current issues with your code:
You're creating a Swing GUI and running it off of the Swing event dispatch thread or EDT. GUI's should be started on the event thread so that all Swing code is guaranteed to run on a single thread.
You've got a long-running while loop, and it is making Swing mutational calls, updating the state of a JButton. If this code were running on the Swing event thread, it would block/freeze the GUI. This block should be explicitly called in a background thread that is not the EDT, and all Swing calls should be queued onto the event thread as per the Lesson: Concurrency in Swing tutorial.
You're using a non-volatile boolean in different threads, risking the variable not being changed when it should be changed
You appear to be closing your streams immediately, preventing adequate communication between concerns.
Working on a cleaner example.......
For example:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import javax.swing.*;
public class SimpleServerClient {
private static final int PORT = 9001;
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
try {
SimpleServer server = new SimpleServer(PORT, "Server", false);
SimpleClient client = new SimpleClient(PORT, "Client", true);
server.createGui();
client.createGui();
} catch (IOException e) {
e.printStackTrace();
}
});
}
}
interface SimpleGui {
void sendLine(String nextLine);
}
// background thread handles listening to the Scanner
// which scans a Socket's InputStream
class MyWorker extends SwingWorker<Void, Void> {
public static final String LINE = "line";
private Scanner inputScanner;
private SimpleGui gui;
private String line = "";
public MyWorker(Scanner inputScanner, SimpleGui gui) {
this.inputScanner = inputScanner;
this.gui = gui;
}
#Override
protected Void doInBackground() throws Exception {
while (inputScanner.hasNext()) {
// get line from Scanner
// use the setter method in case we want to use a PropertyChangeListener later
setLine(inputScanner.nextLine());
// send line to the GUI
gui.sendLine(getLine());
}
return null;
}
public String getLine() {
return line;
}
// again rigged up to allow use of PropertyChangeListeners
public void setLine(String line) {
this.line = line;
firePropertyChange(LINE, null, line);
}
}
// code that both the client and server GUI classes share
abstract class DefaultGui implements SimpleGui {
// this guy ***must**** be volitile!
private volatile boolean myTurn;
protected Scanner inputScanner;
protected PrintStream out;
protected JButton button = new JButton("Blank");
protected Socket socket;
protected String name;
protected int port;
public DefaultGui(int port, String name, boolean myTurn) {
this.port = port;
this.name = name;
this.myTurn = myTurn;
}
#Override
public void sendLine(String nextLine) {
button.setText(nextLine);
myTurn = true;
}
public void createGui() {
button.addActionListener(e -> actionPerformed(e));
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(300, 300));
panel.add(button);
JFrame frame = new JFrame(getName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
protected void actionPerformed(ActionEvent e) {
if (!myTurn) {
return;
}
out.println(getName());
button.setText(getName());
myTurn = false;
}
public String getName() {
return name;
}
}
class SimpleServer extends DefaultGui {
private ServerSocket serverSocket;
public SimpleServer(int port, String name, boolean myTurn) throws IOException {
super(port, name, myTurn);
serverSocket = new ServerSocket(port);
new Thread(() -> {
try {
// accept() blocks the current thread, so must be called on a background thread
socket = serverSocket.accept();
inputScanner = new Scanner(socket.getInputStream());
out = new PrintStream(socket.getOutputStream(), true);
new MyWorker(inputScanner, this).execute();
} catch (IOException e) {
e.printStackTrace();
}
}).start();
}
}
class SimpleClient extends DefaultGui {
public SimpleClient(int port, String name, boolean myTurn) throws IOException {
super(port, name, myTurn);
socket = new Socket("localhost", port);
inputScanner = new Scanner(socket.getInputStream());
out = new PrintStream(socket.getOutputStream());
new MyWorker(inputScanner, this).execute();
}
}

GUI is not responding to button clicks

I'm trying to write a simple port scanner in Java. It works, but the entire window stops responding to clicks once the scanning begins. This won't allow me to use the stop button to pause the operation or exit the window. Here is my code:
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import javax.swing.*;
import java.awt.event.*;
public class GUIScanner {
JFrame frame = new JFrame("Port Scanner");
JTextField textField = new JTextField("",20);
JPanel panel = new JPanel();
JButton button = new JButton("Scan");
JButton button2 = new JButton("Stop");
JLabel label = new JLabel("");
boolean stopped = false;
public GUIScanner() {
initialize();
}
public static void main(String[] args) {
GUIScanner scanner = new GUIScanner();
}
public void initialize() {
panel.add(textField);
panel.add(button);
panel.add(button2);
frame.add(panel);
frame.setSize(500, 500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String address = textField.getText().toString();
scanHost(address, 200);
}
});
button2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(!stopped) {
stopped = true;
button2.setText("Resume");
} else {
stopped = false;
button2.setText("Stop");
}
}
});
}
public void scanHost(String ip, int timeout) {
while(!stopped) {
button2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(!stopped) {
stopped = true;
button2.setText("Resume");
} else {
stopped = false;
button2.setText("Stop");
}
}
});
for(int port = 0; port <= 65535; port++) {
frame.setTitle("Scanning port " + port + " of 65535");
Socket socket = new Socket();
try {
socket.connect(new InetSocketAddress(ip, port), timeout);
socket.close();
System.out.println(port);
} catch (IOException e) {
}
}
}
}
}
I'm not sure if the issue is a threading issue or if it is something else in my code. I'm fairly inexperienced with Java. I'm using Eclipse Oxygen if that helps.

Use a SwingWorker to run another thread in the background. This prevents Swing from being blocked when you pause the background thread. Here is the corrected version of the port scanner code:
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import javax.swing.*;
import java.awt.event.*;
public class GUIScanner {
JFrame frame = new JFrame("Port Scanner");
JTextField textField = new JTextField("", 20);
JPanel panel = new JPanel();
JButton button = new JButton("Scan");
JButton button2 = new JButton("Stop");
JLabel label = new JLabel("");
boolean stopped = false;
PausableSwingWorker<Void, String> scanningWorker;
abstract class PausableSwingWorker<K, V> extends SwingWorker<K, V> {
private volatile boolean isPaused;
final Object lock = new Object();
public final void pause() {
if (!isPaused() && !isDone()) {
isPaused = true;
}
}
public final void resume() {
if (isPaused() && !isDone()) {
isPaused = false;
synchronized(lock) {
lock.notify();
}
}
}
public final boolean isPaused() {
return isPaused;
}
}
public GUIScanner() {
initialize();
}
public static void main(String[] args) {
GUIScanner scanner = new GUIScanner();
}
public void initialize() {
panel.add(textField);
panel.add(button);
panel.add(button2);
frame.add(panel);
frame.setSize(500, 500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String address = textField.getText().toString();
scanHost(address, 200);
}
});
button2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (!stopped) {
stopped = true;
button2.setText("Resume");
scanningWorker.pause();
} else {
stopped = false;
button2.setText("Stop");
scanningWorker.resume();
}
}
});
}
public void scanHost(String ip, int timeout) {
scanningWorker = new PausableSwingWorker<Void, String>() {
#Override
public Void doInBackground() {
for (int port = 0; port <= 65535; port++) {
if (!isPaused()) {
frame.setTitle("Scanning port " + port + " of 65535");
Socket socket = new Socket();
try {
socket.connect(new InetSocketAddress(ip, port), timeout);
socket.close();
System.out.println("Port " + port + " is open");
} catch (IOException e) {
}
}
else {
synchronized(lock) {
try {
lock.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
return null;
}
#Override
public void done() {
}
};
scanningWorker.execute();
}
}

Welcome to the wonderful world of "Honey, I blocked the Event Dispatching Thread".
Start by taking a look at Concurrency in Swing for more of an overview.
Essentially, Swing is single threaded and NOT thread safe. This means you should never perform long running or blocking operations within the context of the EDT, but also, you should not update the UI from outside of the context of the EDT.
Instead, you should consider using something like SwingWorker, which allows you to run blocking/long running operations in the background, but provides functionality to publish and process updates in the EDT

Java error: java.net.BindException: Address already in use: JVM_Bindin server run class

When I run the client program I get this error. I checked to see if the port number is being used and already tried changing the port multiple times.
the server uses three classes:
the main and gui
class ServerGui extends Server implements ActionListener
{
public ServerGui() throws Exception
{
JFrame jfrm = new JFrame("Check in Desk");
jfrm.setLayout(new FlowLayout());
jfrm.setSize(500, 500);
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jfrm.setVisible(true);
//menu bar
JMenuBar jmb = new JMenuBar();
JMenu jmView = new JMenu("View");
// items
JMenu jmEdit = new JMenu("Edit");
// items
JMenu jmHelp = new JMenu("Help");
// items
jmb.add(jmView);
jmb.add(jmEdit);
jmb.add(jmHelp);
//add menuBar
jfrm.setJMenuBar(jmb);
}
public void actionPerformed(ActionEvent ae)
{
String comString = ae.getActionCommand();
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
try{
new ServerGui();
}
catch(Exception e)
{
System.out.println(e + "damn");
}
}
});
}
}
The server class
public class Server extends Thread
{
public Server() throws IOException
{
this.start();
}
public void run()
{
try
{
while(true)
{
ServerSocket socketOnWhichToListenForClients= new ServerSocket(9876);
Socket socketBackToClient = socketOnWhichToListenForClients.accept();
new ClientHandler(socketBackToClient);
}
}
catch(Exception e)
{
System.out.println(e + "in server run class");
}
}
}
client handler
public class ClientHandler extends Thread
{
private Socket socketBackToClient;
public ClientHandler(Socket socket)
{
socketBackToClient = socket;
this.start();
}
public void run()
{
try
{
InputStream is = socketBackToClient.getInputStream();
BufferedReader message = new BufferedReader(new InputStreamReader(is));
String input = message.readLine();
System.out.println(input);
socketBackToClient.close();
}
catch(Exception e)
{
System.out.println("Error");
}
}
}
The client gui
public class ClientGui extends Client implements ActionListener
{
//private String name = "";
public ClientGui() throws Exception
{
name = JOptionPane.showInputDialog("Enter your name.");
if(name.equals(""))
return;
JFrame jfrm = new JFrame("Check in Desk");
jfrm.setLayout(new FlowLayout());
jfrm.setSize(300, 170);
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jfrm.setVisible(true);
jfrm.setResizable(false);
//buttons
Font font1 = new Font("SansSerif",Font.PLAIN, 24);
Font font2 = new Font("SansSerif",Font.PLAIN, 20);
JButton jb1 = new JButton("Help");
jb1.setPreferredSize(new Dimension(100, 100));
jfrm.add(jb1);
JButton jb2 = new JButton("Check In");
jb2.setPreferredSize(new Dimension(125, 100));
jfrm.add(jb2);
jb1.setFont(font1);
jb2.setFont(font2);
//menu bar
JMenuBar jmb = new JMenuBar();
JMenu jmTools = new JMenu("Tools");
JMenuItem jmiName = new JMenuItem("Name");
JMenuItem jmiIP = new JMenuItem("Your IP");
jmTools.add(jmiName);
jmTools.add(jmiIP);
// items
JMenu jmEdit = new JMenu("Edit");
// items
JMenu jmHelp = new JMenu("Help");
JMenuItem jmiAbout = new JMenuItem("About");
jmHelp.add(jmiAbout);
// items
jmb.add(jmTools);
jmb.add(jmEdit);
jmb.add(jmHelp);
//add menuBar
jfrm.setJMenuBar(jmb);
jmiName.addActionListener(this);
jmiIP.addActionListener(this);
jb1.addActionListener(this);
jb2.addActionListener(this);
}
public void actionPerformed(ActionEvent ae)
{
String confirmHelp = "";
String confirmCheckIn = "";
if(ae.getActionCommand().equals("Name"))
JOptionPane.showMessageDialog(null,"Your name is " + getClientName());
if(ae.getActionCommand().equals("Your IP"))
JOptionPane.showMessageDialog(null,"Your IP is " + getIpAddress());
if(ae.getActionCommand().equals("Help"))
{
confirmHelp = JOptionPane.showInputDialog("Are You Sure You Want Help?");
if(confirmHelp != null && confirmHelp.equalsIgnoreCase("yes"))
{
Help();
}
}
if(ae.getActionCommand().equals("Check In"))
{
confirmCheckIn = JOptionPane.showInputDialog("Are You Sure You Want To Check In?");
if(confirmCheckIn != null && confirmCheckIn.equalsIgnoreCase("yes"))
{
CheckIn();
}
}
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
try{
new ClientGui();
Socket socket = new Socket(InetAddress.getLocalHost(), 9876); //new Client(); // add constructor with name or pc numb
}
catch(Exception e)
{
System.out.println("client closed");
}
}
});
}
}
The client
public class Client
{
public String name = "";
Socket clientSocket;
public Client() throws Exception
{
try
{
// clientSocket = new Socket(InetAddress.getLocalHost(), 9);
OutputStream os = clientSocket.getOutputStream();
PrintWriter pwrite = new PrintWriter(os, true);
pwrite.print("yolo");
}
catch(Exception e)
{
//System.out.println("Error cant connect"); add later
}
}
public void Help()
{
System.out.println("you pressed help");
}
public void CheckIn()
{
System.out.println("you pressed Check In");
}
public String getIpAddress()
{
String str = "";
try{
InetAddress ip = InetAddress.getLocalHost();
str = ip.toString();
}
catch(UnknownHostException e)
{
System.out.println("can not find IP address");
}
return str;
}
public String getClientName()
{
return name;
}
}

The problem is that you keep recreating the ServerSocket inside the while loop. Create it once, before the loop.

The problem is at below lines where same port is used in loop to create ServerSocket that results into below exception.
try {
while (true) {
ServerSocket socketOnWhichToListenForClients = new ServerSocket(9876);
}
} catch (Exception e) {
System.out.println(e + "in server run class");
}
Look at at the exception:
java.net.BindException: Address already in use: JVM_Bindin server run class
Don't forget to close the ServerSocket in the end. Use finally block to close it.

add jbutton at runtime

I am building an application on Socket programming in swing in which server listens for clients and if a client is connected I want
A button should be added for each client if connected on server screen
Add a listener on each button.For example add Send Message function for each client
I have created a thread in server which listens for client connections but I can not add jbutton at runtime.
Please reply.

Is that what you need ? :
import javax.swing.*;
import java.awt.event.*;
public class NewButtonOnRunTime {
static JPanel panel;
static JFrame frame;
public static void main(String[] args){
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
frame = new JFrame("Add Buttons");
JButton button = new JButton("Simulate new Client");
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
JButton jb = new JButton("A new Client");
jb.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null, "This is an button action");
}
});
panel.add(jb);
frame.revalidate();
}
});
panel = new JPanel();
panel.add(button);
frame.add(panel);
frame.setSize(400, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}

Assuming you already have some kind of isConnected bool,
if(isConnected){
JButton runTimeButton = new JButton();
runTimeButton.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
//do all the things you need to do in here,
//alternatively, define this inner class somewhere else and pass in
// an instance of it
}
});
frame.add(runTimeButton);
}

Based on ServerSocket communication in java (i.e. TCP), if a client is connected to the server with a particular port say 5555, no other clients will not be able to connect to the server with the same port at the same time because the port is already in use. So, each client should be using different port if you want to get simultaneous communication with the clients.
Look at this sample code, it adds JButton at runtime when a new client is connected :
(run client code and server code in separate machine connected together)
Server code
package com.test.socket;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextArea;
public class ServerFrame extends JFrame {
private Map<Integer, SocketVO> serverSocketMap;
private int startingPort = 5555;
public ServerFrame() {
}
public ServerFrame(String title) {
super(title);
setSize(Toolkit.getDefaultToolkit().getScreenSize());
setLayout(new FlowLayout());
initComponents();
serverSocketMap = new HashMap<Integer, SocketVO>();
keepStartServerSocket();
setVisible(true);
}
private JTextArea area = null;
private void initComponents() {
area = new JTextArea(20, 20);
add(area);
// addDynamicButton();
}
private void addDynamicButton(final int port) {
JButton button = new JButton("Client on " + port + " port");
add(button);
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
Socket socket = serverSocketMap.get(port).getSocket();
try {
String content = area.getText();
socket.getOutputStream().write(content.getBytes());
System.out.println("seding text area content to " + port);
System.out.println(content);
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
class SocketVO {
private ServerSocket serverSocket;
private Socket socket;
public ServerSocket getServerSocket() {
return serverSocket;
}
public void setServerSocket(ServerSocket serverSocket) {
this.serverSocket = serverSocket;
}
public Socket getSocket() {
return socket;
}
public void setSocket(Socket socket) {
this.socket = socket;
}
}
private void keepStartServerSocket() {
new Thread(new Runnable() {
#Override
public void run() {
while (true) {
System.out.println("waiting for a client at port "
+ startingPort);
openServerSocket(startingPort);
startingPort++;
}
}
}).start();
}
private void openServerSocket(final int port) {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(port);
final Socket socket = serverSocket.accept();
SocketVO socketVO = new SocketVO();
socketVO.setServerSocket(serverSocket);
socketVO.setSocket(socket);
serverSocketMap.put(port, socketVO);
addDynamicButton(port);
checkForCosing(port, socket);
} catch (IOException e) {
e.printStackTrace();
}
}
private void checkForCosing(final int port, final Socket socket) {
new Thread(new Runnable() {
#Override
public void run() {
InputStream inputStream = null;
try {
inputStream = socket.getInputStream();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
byte[] b = new byte[1024];
int read = 0;
try {
StringBuilder builder = new StringBuilder();
while ((read = inputStream.read(b)) != -1) {
builder.append(new String(b));
}
if (builder.toString().equals("close")) {
closeServerSocket(port);
System.out.println("server port " + port + " closed");
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}).start();
}
/**
* the method to close corresponding sockets
*
* #param port
*/
private void closeServerSocket(int port) {
Socket socket = serverSocketMap.get(port).getSocket();
ServerSocket serverSocket = serverSocketMap.get(port).getServerSocket();
try {
socket.close();
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
new ServerFrame("Server Socket Frame");
}
}
Client code :
package com.test.socket;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class Client {
private int startingPort = 5550;
private void bindToServer() {
while(true) {
try {
Socket socket = new Socket("127.0.0.1", startingPort);
InputStream inputStream = null;
try {
inputStream = socket.getInputStream();
} catch (IOException e1) {
e1.printStackTrace();
}
byte[] b = new byte[1024];
int read = 0;
try {
StringBuilder builder = new StringBuilder();
while((read = inputStream.read(b)) != -1) {
builder.append(new String(b));
}
System.out.println("message from server : "+builder);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
startingPort++;
}
if (startingPort == 5580) {
}
}
}
public static void main(String[] args) {
new Client().bindToServer();
}
}

As per your last comment:
I have tested the program with two clients. The server is connected to two clients successfully. But buttons are not added at runtime for each client.
You are able to connect with multiple client and you have added a button also but it's not visible on the server.
Calling validate() again on JFrame will solve your problem after adding new JButton.

public class Test extends JFrame {
private JButton field[];
public JButton[] getField() {
return field;
}
public void test(int n) {
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(0, 1));
field = new JButton[n];
for (int i = 0; i < field.length; i++) {
field[i] = new JButton("" + i + "");
field[i].addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
System.out.println("clicked button");
}
});
panel.add(field[i]);
}
add(panel);
}
public static void main(String[] args) {
Test test = new Test();
test.setSize(300, 300);
test.setVisible(true);
test.setLocationRelativeTo(null);
test.test(5);
}
}

Starting a thread in a Swing event

I'm working on the client side application of the client/server chat I'm doing for learning experience. My problem is I can't seem to get the socket and swing,both to run at the same time.
What I want to is, when the user opens a JOpionsPane and enters the hostname and port number, clicks okay, then they are connected. When the socket information was hardcoded it worked fine, but now I'm trying to get the users input for it.
What's meant to happen is, action listener is supposed to create the new SocketManager object that handles communication. Event though it says it's connected, it doesn't run. When I create the new SocketManager object and run it on a new thread it connects and revives messages form the server, but then the swings freezes and I have to end the process to shut it down.
Should I start it on a new worker thread or something? Maybe it's just because I'm tired, but I'm out of ideas.
EDIT
I updated my ActLis.class and SocketManager.class with the suggestion of adding a new thread for my SocketManager object 'network'. When I try and use 'network' though it returns null for some reason.
ActLis.clss
package com.client.core;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class ActLis implements ActionListener {
private Main main = new Main();;
private JTextField ipadress = new JTextField(),
portnumber = new JTextField(),
actionField;
private String username;
final JComponent[] ipinp = new JComponent[]{new JLabel("Enter Hostname (IP Adress): "),
ipadress,
new JLabel("Enter Port number: "), portnumber};
private SocketManager network;
private Window win;
public ActLis(){
}
public ActLis(JTextField t, Window w){
actionField = t;
win = w;
}
#Override
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
if(cmd == "Exit"){
System.exit(0);
} else if(cmd == "Connect to IP"){
try{
JOptionPane.showMessageDialog(null, ipinp, "Connect to IP", JOptionPane.PLAIN_MESSAGE);
if(network != null){
network.close();
}
network = new SocketManager(ipadress.getText(),Integer.parseInt(portnumber.getText()));
network.setGUI(win);
Thread t = new Thread(network);
t.start();
JOptionPane.showMessageDialog(null, "Connected to chat host successfully!","Connected", JOptionPane.INFORMATION_MESSAGE);
}catch(Exception ee){
JOptionPane.showMessageDialog(null, "Could not connect. Check IP adress or internet connection","Error - Could not connect", JOptionPane.ERROR_MESSAGE);
ee.printStackTrace();
}
} else if (cmd == "chatWriter"){
if( actionField.getText() != ""){
try{
network.send(actionField.getText());
win.updateChat(actionField.getText());
actionField.setText("");
actionField.requestFocus();
}catch(Exception ex){
JOptionPane.showMessageDialog(null, "You are not connected to a host. (File -> Connect to IP)","Error - Not Connected", JOptionPane.ERROR_MESSAGE);
ex.printStackTrace();
}
}
} else if (cmd == "setUsername"){
username = actionField.getText();
network.send("USERNAME:" + username);
}
}
}
Main.class
package com.client.core;
import javax.swing.JFrame;
public class Main extends JFrame{
private SocketManager network;
public static void main(String[] args){
Main main = new Main();
main.run();
}
private void run(){
Window win = new Window();
win.setVisible(true);
}
}
SocketManager.class
package com.client.core;
import java.io.*;
import java.net.*;
public class SocketManager implements Runnable {
private Socket sock;
private PrintWriter output;
private BufferedReader input;
private String hostname;
private int portnumber;
private String message;
private Window gui;
public SocketManager(String ip, int port){
try{
hostname = ip;
portnumber = port;
}catch(Exception e){
System.out.println("Client: Socket failed to connect.");
}
}
public synchronized void send(String data){
try{
//System.out.println("Attempting to send: " + data);
output.println(data);
output.flush();
//System.out.println("Message sent.");
}catch(Exception e){
System.out.println("Message could not send.");
}
}
public synchronized void setGUI(Window w){
gui = w;
}
public synchronized void connect(){
try{
sock = new Socket(hostname,portnumber);
}catch(Exception e){
}
}
public synchronized Socket getSocket(){
return sock;
}
public synchronized void setSocket(SocketManager s){
sock = s.getSocket();
}
public synchronized void close(){
try{
sock.close();
}catch(Exception e){
System.out.println("Could not close connection.");
}
output = null;
input = null;
System.gc();
}
public synchronized boolean isConnected(){
return (sock == null) ? false : (sock.isConnected() && !sock.isClosed());
}
public synchronized void listenStream(){
try {
while((message = input.readLine()) != null){
System.out.println("Server: " + message);
gui.updateChat(message);
}
} catch (Exception e) {
}
}
#Override
public void run() {
try {
sock = new Socket(hostname,portnumber);
output = new PrintWriter(sock.getOutputStream(),true);
input = new BufferedReader(
new InputStreamReader(sock.getInputStream()));
while(true){
listenStream();
}
} catch (Exception e) {
System.out.println("Run method fail. -> SocketManager.run()");
}finally{
try {
sock.close();
} catch (Exception e) {
}
}
}
}
Window.class
package com.client.core;
import java.awt.*;
import javax.swing.*;
public class Window extends JFrame{
private int screenWidth = 800;
private int screenHeight = 600;
private SocketManager network;
private JPanel window = new JPanel(new BorderLayout()),
center = new JPanel(new BorderLayout()),
right = new JPanel(new BorderLayout()),
display = new JPanel( new BorderLayout()),
chat = new JPanel(),
users = new JPanel(new BorderLayout());
private JTextArea chatBox = new JTextArea("Welcome to the chat!", 7,50),
listOfUsers = new JTextArea("None Online");
private JTextField chatWrite = new JTextField(),
userSearch = new JTextField(10),
username = new JTextField();
private JScrollPane userList = new JScrollPane(listOfUsers),
currentChat = new JScrollPane(chatBox);
private JMenuBar menu = new JMenuBar();
private JMenu file = new JMenu("File");
private JMenuItem exit = new JMenuItem("Exit"),
ipconnect = new JMenuItem("Connect to IP");
private JComponent[] login = new JComponent[]{new JLabel("Username:"), username};
public Window(){
//Initial Setup
super("NAMEHERE - Chat Client Alpha v0.0.1");
setResizable(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(screenWidth,screenHeight);
//Panels
listOfUsers.setLineWrap(true);
listOfUsers.setEditable(false);
display.setBackground(Color.black);
chat.setLayout(new BoxLayout(chat, BoxLayout.Y_AXIS));
chat.setBackground(Color.blue);
users.setBackground(Color.green);
//TextFields
addChatArea();
//Menu bar
addMenuBar();
//Adding the main panels.
addPanels();
//Listeners
addListeners();
for(int x = 0; x < 1; x++){
login();
}
}
private void login(){
JOptionPane.showMessageDialog(null, login, "Log in", JOptionPane.PLAIN_MESSAGE);
}
private void addChatArea(){
chatBox.setEditable(false);
userList.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
currentChat.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
users.add(userList);
users.add(userSearch, BorderLayout.NORTH);
chat.add(currentChat);
chat.add(chatWrite);
chat.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
}
private void addMenuBar(){
file.add(ipconnect);
file.add(exit);
menu.add(file);
}
private void addPanels(){
right.add(users);
center.add(display, BorderLayout.CENTER);
center.add(chat, BorderLayout.SOUTH);
window.add(center, BorderLayout.CENTER);
window.add(right, BorderLayout.EAST);
window.add(menu, BorderLayout.NORTH);
add(window);
}
private void addListeners(){
username.addActionListener(new ActLis(username, this));
chatWrite.addActionListener(new ActLis(chatWrite, this));
username.setActionCommand("setUsername");
chatWrite.setActionCommand("chatWriter");
ipconnect.addActionListener(new ActLis());
exit.addActionListener(new ActLis());
}
public void setNetwork(SocketManager n){
network = n;
}
public void updateChat(String s){
chatBox.setText(chatBox.getText() + "\n" + s);
}
}

Ok #Zexanima you have create a Socket class for socket manager. Something like this:
public class YouSocketClass {
static public Socket socket = null;
static public InputStream in = null;
static public OutputStream out = null;
public YouSocketClass() {
super();
}
public static final Socket getConnection(final String ip, final int port, final int timeout) {
try {
socket = new Socket(ip, port);
try {
socket.setSoTimeout(timeout);
} catch(SocketException se) {
log("Server Timeout");
}
in = socket.getInputStream();
out = socket.getOutputStream();
} catch(ConnectException e) {
log("Server name or server ip is failed. " + e.getMessage());
e.printStackTrace();
} catch(Exception e) {
log("ERROR Socket: " + e.getMessage() + " " + e.getCause());
e.printStackTrace();
}
return socket;
}
public static void closeConnection() {
try {
if(socket != null) {
if(in != null) {
if(out != null) {
socket.close();
in.close();
out.close();
}
}
}
} catch(Exception e2) {
e2.printStackTrace();
}
}
private static Object log(Object sms) {
System.out.println("Test Socket1.0: " + sms);
return sms;
}
}
I hope that serve. :)