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Handle Java Socket connection between 2 JFrames

I'm trying to create a client/server application using sockets, I have 2 JFrames (2 seperate classes) , a user will initially open up the one frame and there's a button to go to the other JFrame, when clicked it disposes the previous frame and opens the new frame.
I'd like to know how I could switch back and forth between these 2 JFrames without my program crashing and needing to forcefully close, I am establishing the connection in the constructor of each JFrame.
try {
server = new Socket("localhost", PORT);
// creates & instantiates objectInput and output streams
getStreams();
} catch (IOException ex) {
System.out.println("error creating socket: " + ex.getMessage());
}
I have these in the constructor of both JFrames
EDIT
Server
public class Testserver {
private ServerSocket serverSocket;
private Socket client;
private final int PORT = 5432;
private ObjectOutputStream objectOutputStream;
private ObjectInputStream objectInputStream;
public Testserver() {
try {
serverSocket = new ServerSocket(PORT);
} catch (IOException ex) {
JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
System.out.println("error creating server socket: " + ex.getMessage());
}
}
private void listenForClient() {
try {
System.out.println("Server is running and is waiting/listening for a connection to be established.");
////JOptionPane.showMessageDialog(null, "Server is running and is waiting/listening for a connection to be established." );
client = serverSocket.accept();
System.out.println("A client has connected");
objectOutputStream = new ObjectOutputStream(client.getOutputStream());
objectInputStream = new ObjectInputStream(client.getInputStream());
processClient();
} catch (IOException ex) {
JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
}
}
private void processClient() {
do {
try {
String messageFromClient = (String) objectInputStream.readObject();
// check for clients requests and handle them (database etc)
System.out.println("[CLIENT] " + messageFromClient);
} catch (IOException ex) {
Logger.getLogger(Testserver.class.getName()).log(Level.SEVERE, null, ex);
break;
} catch (ClassNotFoundException ex) {
Logger.getLogger(Testserver.class.getName()).log(Level.SEVERE, null, ex);
break;
}
} while (true);
closeConnections();
}
private void closeConnections() {
try {
objectInputStream.close();
objectInputStream.close();
client.close();
} catch (IOException ex) {
JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
}
}
public static void main(String[] args) {
new Testserver().listenForClient();
}
}
CustomerGUI
public class CustomerGUI extends JFrame implements ActionListener{
private Socket server;
private ObjectOutputStream objectOutputStream;
private ObjectInputStream objectInputStream;
private JPanel panel1;
private JButton btnAdminGUI;
private final int PORT = 5432;
public CustomerGUI() {
btnAdminGUI = new JButton("Go to Admin GUI");
try {
server = new Socket("localhost", PORT);
System.out.println("Connected to server");
objectOutputStream = new ObjectOutputStream(server.getOutputStream());
objectInputStream = new ObjectInputStream(server.getInputStream());
objectOutputStream.writeObject("from Customer");
objectOutputStream.flush();
} catch (IOException ex) {
JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage()););
}
btnAdminGUI.addActionListener(this);
}
public void setGUI() {
add(btnAdminGUI);
setSize(300, 400);
setVisible(true);
}
public static void main(String[] args) {
new CustomerGUI().setGUI();
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == btnAdminGUI) {
new AdminGUI().setGUI();
dispose();
}
}
}
AdminGUI
public class AdminGUI extends JFrame implements ActionListener{
private Socket server;
private ObjectOutputStream objectOutputStream;
private ObjectInputStream objectInputStream;
private JPanel panel1;
private JButton btnCustomerGUI;
private final int PORT = 5432;
public AdminGUI() {
btnCustomerGUI = new JButton("Go to Customer GUI");
try {
server = new Socket("localhost", PORT);
System.out.println("Connected to server");
objectOutputStream = new ObjectOutputStream(server.getOutputStream());
objectInputStream = new ObjectInputStream(server.getInputStream());
objectOutputStream.writeObject("from Admin");
objectOutputStream.flush();
} catch (IOException ex) {
JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
}
btnCustomerGUI.addActionListener(this);
}
public void setGUI() {
add(btnCustomerGUI);
setSize(300, 400);
setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == btnCustomerGUI) {
new CustomerGUI().setGUI();
dispose();
}
}
}

I'll post a solution this because I have done something similar recently, but I don't have a UI for it yet.
The idea is MVC, with two models, a Server and Client and there are two Views, JPanels, which can be displayed in a window/jframe/dialog, whichever is appropriate. The Controller is essentially an api for interacting with the model, for this simple example the controllers will be mixed with the models. I think this example has a lot of flaws, but I think it gives a good idea of what needs to be done.
A button starts a course of action,
serverControls.addActionListener( evt ->{ } );
The button does one of two actions, either it starts the server or it stops the server.
serverLoop.submit( ()->{
server.listen();
//should notify a listener that the server has stopped.
});
serverLoop is another thread of execution, server.listen() is a long running task. It shouldn't return until we want the server to stop listening.
The other button is on the client. It has a similar structure..
clientControls.addActionListener( evt->{
clientLoop.submit( () -> client.connect( server ) );
clientLoop.submit(
() -> SwingUtilities.invokeLater(
() -> response.setText( client.communicate() )
)
);
});
First the client is going to connect, then it communicates.
import javax.swing.*;
import java.util.concurrent.*;
public class ClientServerApp{
static class Server{
volatile boolean available = false;
public void listen(){
try{
available = true;
synchronized( this ){
wait(5000);
}
} catch(Exception e){
e.printStackTrace();
//if the server terminates unexpectedly.
}finally{
available = false;
}
}
public void stopListening(){
}
}
static class Client{
Server connected;
public void connect(Server host){
connected = host;
}
public String communicate(){
if(connected != null){
if(connected.available){
return "connected";
} else{
return "cannot connect";
}
}
return "no host";
}
}
public static void main(String[] args){
Server server = new Server();
Client client = new Client();
ExecutorService serverLoop = Executors.newSingleThreadExecutor();
JPanel serverView = new JPanel();
JButton serverControls = new JButton("start");
serverView.add( serverControls );
serverControls.addActionListener( evt ->{
if(serverControls.getText().equals("start") ){
serverControls.setText("stop");
serverLoop.submit( ()->{
server.listen();
//should notify a listener that the server has stopped.
});
} else{
server.stopListening();
serverLoop.submit( ()->{
//will be run after the listen loop has completed.
SwingUtilities.invokeLater( () - >
serverControls.setText("start")
);
});
}
} );
JPanel clientView = new JPanel();
JButton clientControls = new JButton("connect");
JTextField response = new JTextField(40);
clientView.add( clientControls );
clientView.add(response);
ExecutorService clientLoop = Executors.newSingleThreadExecutor();
System.out.println("creating client action listener");
clientControls.addActionListener( evt->{
clientLoop.submit( () -> client.connect( server ) );
clientLoop.submit( () ->
SwingUtilities.invokeLater(
() -> response.setText( client.communicate() )
)
);
});
JFrame mainWindow = new JFrame();
mainWindow.setContentPane( serverView);
mainWindow.pack();
mainWindow.setVisible(true);
JDialog clientWindow = new JDialog( mainWindow, "Client Window");
clientWindow.setContentPane(clientView);
clientWindow.pack();
clientWindow.setVisible(true);
}
}
In a more complete example, you would probably have a Listener interface, so that your swing gui can response to changes in state of the server or the client, and a controller that manages the threads.

Java Multiple threads using a client socket

I'm creating a server based chat program that has multiple worker threads each handling a client on a socket. It has a single server socket that passes off the client to the worker thread.
public static void main(String[] args) {
ExecutorService executor = Executors.newFixedThreadPool(5);
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(4001);
System.out.println("Listening server");
while (true) {
Socket socket = serverSocket.accept();
System.out.println("Connected");
Random rand= new Random();
int port=4001+rand.nextInt(5);
Worker worker = new Worker(port);
executor.execute(worker);
System.out.println("Thread started");
new PrintWriter(socket.getOutputStream(), true).println(port);
socket.close();
System.out.println("Closed");
// break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
public class Worker implements Runnable {
private int port;
public Worker(int i) {
port=i;
}
#Override
public void run() {
worker();
}
private static Socket socket;
private static PrintWriter out;
private static BufferedReader in;
private void worker() {
try {
ServerSocket serverSocket = new ServerSocket(port);
socket = serverSocket.accept();
out = new PrintWriter(socket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line;
while ((line = in.readLine()) != null) {
System.out.println("Received: " + line);
switch (line) {
case ("Button Press"):
System.out.println("Handled button");
out.println("Button acknowledged");
break;
case ("Give me some data"):
System.out.println("Handled data");
out.println("Have some data");
break;
}
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
out.close();
in.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
This works fine, however the issue is when I have an automated request by the client to check for messages and the user provides some input at the same type. This causes conflict as the actual methods take a couple of seconds to run and if more input is received then the request won't be handled because its in the middle of the method. For example:
private static BufferedReader in;
private static PrintWriter out;
public static void main(String[] args) {
Main main=new Main();
main.createWindow();
try {
Socket init = new Socket(InetAddress.getLocalHost(), 4001);
int port
=Integer.parseInt
(new BufferedReader
(new InputStreamReader(init.getInputStream())).readLine());
init.close();
Socket socket=new Socket(InetAddress.getLocalHost(), port);
out = new PrintWriter(socket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while(true){
try {
Thread.sleep(5000);
out.println("Give me some data");
if(in.readLine().equals("Have some data")){
System.out.println("Data recieved");
}else{
System.out.println("Data not recieved");
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
private void createWindow(){
JFrame frame =new JFrame("This is a button");
Container pane=getContentPane();
JButton button=new JButton("This is a button");
button.addActionListener(this);
pane.add(button);
frame.setTitle("Messaging");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(pane);
frame.setVisible(true);
frame.setSize(400, 350);
}
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Button press");
try {
out.println("Button Press");
if(in.readLine().equals("Button acknowledged")){
System.out.println("Button complete");
}else{
System.out.println("Button fail");
}
} catch (IOException e1) {
e1.printStackTrace();
}
}
If the button is pressed whilst the server is fetching data it conflicts and the wrong response is sent. So how would I deal with this? If I create a separate socket to just handle automated checks that's double the amount of threads the server has to cope with. Is there a better solution?
And please can you try to explain as this is a new area for me.

Your problem is that you have two threads interacting with the socket, your main thread and the Swing event handling thread. This means that the two threads can queue two different things, and the responses may be picked up by the wrong thread. The simplest way to get where you want to be is to put all the socket interaction in one thread.
There are two ways to do this. One would be for the main thread to queue the periodic automated checks to the Swing event handling thread. However, that's a bit complicated and also possibly buggy as the actual Swing threading model is different from what's documented.
The other way to do it would be for the Swing event handling thread to queue button presses to the main thread. In this case, you would queue the button press to the main thread using proper synchronization. The main loop of the main thread would check for button presses and send them through the socket and wait for the proper response.

Issue with Java Server class and socket connections

I am trying to set up a server class, and i'm running into a issue in which no error is being thrown.
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Server extends JFrame implements Runnable{
private static final long serialVersionUID = 1L;
private JTextField userText;
private JTextArea chatWindow;
private ObjectOutputStream output;
private ObjectInputStream input;
private ServerSocket server;
private Socket connection;
//constructor
public Server(){
super("Server");
userText = new JTextField();
userText.setEditable(false);
userText.addActionListener(
new ActionListener(){
public void actionPerformed(ActionEvent event){
sendMessage(event.getActionCommand());
userText.setText("");
}
}
);
add(userText, BorderLayout.NORTH);
chatWindow = new JTextArea();
add(new JScrollPane(chatWindow));
setSize(300, 150); //Sets the window size
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public void run(){
try{
server = new ServerSocket(6789, 100); //6789 is a dummy port for testing, this can be changed. The 100 is the maximum people waiting to connect.
while(true){
try{
//Trying to connect and have conversation
waitForConnection();
setupStreams();
whileChatting();
}catch(EOFException eofException){
showMessage("\n Server ended the connection! ");
} finally{
closeConnection(); //Changed the name to something more appropriate
}
}
} catch (IOException ioException){
ioException.printStackTrace();
}
}
//wait for connection, then display connection information
private void waitForConnection() throws IOException{
showMessage(" Waiting for someone to connect... \n");
connection = server.accept();
showMessage(" Now connected to " + connection.getInetAddress().getHostName());
}
//get stream to send and receive data
private void setupStreams() throws IOException{
output = new ObjectOutputStream(connection.getOutputStream());
output.flush();
input = new ObjectInputStream(connection.getInputStream());
showMessage("\n Streams are now setup \n");
}
//during the chat conversation
private void whileChatting() throws IOException{
String message = " You are now connected! ";
sendMessage(message);
ableToType(true);
do{
try{
message = (String) input.readObject();
showMessage("\n" + message);
}catch(ClassNotFoundException classNotFoundException){
showMessage("The user has sent an unknown object!");
}
}while(!message.equals("CLIENT - END"));
}
public void closeConnection(){
showMessage("\n Closing Connections... \n");
ableToType(false);
try{
output.close(); //Closes the output path to the client
input.close(); //Closes the input path to the server, from the client.
connection.close(); //Closes the connection between you can the client
}catch(IOException ioException){
ioException.printStackTrace();
}
}
//Send a mesage to the client
private void sendMessage(String message){
try{
output.writeObject("SERVER - " + message);
output.flush();
showMessage("\nSERVER -" + message);
}catch(IOException ioException){
chatWindow.append("\n ERROR: CANNOT SEND MESSAGE, PLEASE RETRY");
}
}
//update chatWindow
private void showMessage(final String text){
SwingUtilities.invokeLater(
new Runnable(){
public void run(){
chatWindow.append(text);
}
}
);
}
private void ableToType(final boolean tof){
SwingUtilities.invokeLater(
new Runnable(){
public void run(){
userText.setEditable(tof);
}
}
);
}
}
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class Menu extends JFrame implements ActionListener{
private static final long serialVersionUID = 1L;
private JButton server;
private JButton client;
private static String Host;
public Menu(){
this.getContentPane().setPreferredSize(new Dimension(300, 300));
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLayout(null);
this.pack();
this.setLocationRelativeTo(null);
server = new JButton();
server.setText("server");
server.setBounds(0, 0, 300, 150);
server.addActionListener(this);
client = new JButton();
client.setText("client");
client.setBounds(0, 150, 300, 150);
client.addActionListener(this);
this.add(server);
this.add(client);
this.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
if(e.getSource() == server){
Server s = new Server();
s.run();
}
if(e.getSource() == client){
Host = JOptionPane.showInputDialog("Enter Server I.P.");
Client c = new Client(Host);
c.run();
}
}
public static void main(String[] args){
new Menu();
}
}
The JFrame is created, but can only be exited by the termination button in eclipse, not the default_exit_on_close operation, and is see through (not opaque as it should be). The client class acts the same way, leading me to believe that the issue is the:
Server s = new Server();
s.run();
since if i have the main method call that, everything works fine.

Your constructor can never exit.
This waitForConnection()/setUpStreams() logic is not appropriate. You need an accept loop that just accepts sockets, constructs a Runnable to handle the connection, and starts a thread. That loop should be in a separate run() method and be executed in a separate thread. Not in a constructor.
NB The Socket that is returned by accept() must be a local variable in that loop, otherwise you are liable to run into concurrency problems.

Java : UI thread not resuming in two-threaded application

I'm currently building a Java application using two threads :
The first thread is about the UI of the application, and also the processing of command received via the bluetooth thread.
The bluetooth thread is bluetooth server waiting for a robot to connect and handling communication.
As of now, the UI thread is in wait() state until the bluetooth thread gets a new message to process.
The problem is, I can trace the notify/notifyAll call from the bluetooth thread, but my UI is not resuming it's activity.
I am now sure I misunderstood something about the proper way to manage synchronized threads, but I can't figure out what's wrong in my software.
Here is the code for the UI :
package mapper;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTable;
public class MapperUI extends JFrame implements Runnable {
private ArrayList<String> messageArray;
public MapperUI(){
super();
build();
this.setVisible(true);
new Thread(this).start();
}
private void build(){
setTitle("SLAM Mapper");
setSize(600,500);
setLocationRelativeTo(null);
setResizable(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setContentPane(buildContentPane());
}
private JPanel buildContentPane(){
JPanel main = new JPanel();
main.setLayout(new BorderLayout());
//TODO Implements auto-generated map after bluetooth communication
MapPanel map = new MapPanel();
main.add(map,BorderLayout.CENTER);
//TODO This fields will be buildt with stored message
JTable positions = new JTable(15,2);
main.add(positions,BorderLayout.EAST);
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
JButton bouton = new JButton("Start");
buttonPanel.add(bouton);
JButton bouton2 = new JButton("Send");
buttonPanel.add(bouton2);
main.add(buttonPanel,BorderLayout.SOUTH);
return main;
}
public synchronized void run(){
MapperCom bt = new MapperCom();
while(true){
try {
System.out.println("Mapper is Waiting......");
wait();
String message = bt.getMessage();
this.messageArray.add(message);
bt.setNextCommand(processMessage(message));
notifyAll();
System.out.println("Mapper Notify");
build();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public String processMessage(String message){
String command = "";
//TODO Build a response
command = "fffff\n";
return command;
}
}
Here is the bluetoothService :
package mapper;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import javax.bluetooth.DiscoveryAgent;
import javax.bluetooth.LocalDevice;
import javax.bluetooth.UUID;
import javax.microedition.io.Connector;
import javax.microedition.io.StreamConnection;
import javax.microedition.io.StreamConnectionNotifier;
public class MapperCom extends Thread {
public final UUID uuid = new UUID(
"27012f0c68af4fbf8dbe6bbaf7aa432a", false);
public final String name = "Server";
public final String url = "btspp://localhost:" + uuid
+ ";name=" + name
+ ";authenticate=false;encrypt=false;";
private LocalDevice local ;
private StreamConnectionNotifier server ;
private StreamConnection conn ;
private DataInputStream din ;
private DataOutputStream dout ;
private String command;
private String message;
public MapperCom(){
try {
this.command = "";
this.message = "";
System.out.println("Setting device to be discoverable...");
local = LocalDevice.getLocalDevice();
local.setDiscoverable(DiscoveryAgent.GIAC);
System.out.println("Start advertising service...");
server = (StreamConnectionNotifier)Connector.open(url);
System.out.println("Waiting for incoming connection...\n");
conn = server.acceptAndOpen();
System.out.println("Client Connected...");
din = new DataInputStream(conn.openInputStream());
dout = new DataOutputStream(conn.openOutputStream());
new Thread(this).start();
} catch (Exception e) {
System.out.println("Exception Occured: " + e.toString());
}
}
#Override
public synchronized void run(){
System.out.println("Bluetooth Thread Started");
while(true){
try {
String cmd = "";
char c;
System.out.println("Waiting for message");
while (((c = din.readChar()) > 0) && (c!='\n') ){
System.out.println("Char received :"+c);
cmd = cmd + c;
}
storeMessage(cmd);
System.out.println("Bt Notify......");
notifyAll();
System.out.println("Bt is Waiting for a command from mapper......");
wait();
sendResponse();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void sendResponse(){
try {
dout.writeChars(command);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public synchronized String getMessage(){
return this.message;
}
public synchronized void storeMessage (String data){
this.message = data;
System.out.println("Received " + data);
}
public synchronized int setNextCommand (String data){
int result = -1;
//TODO Implement proper protocol
this.command = data;
System.out.println("Sending " + data);
return result;
}
}

I think when you call notifyAll(), it calls this.notifyAll(). Which there are no other elements waiting in the same class. So what you can do is you share the same object over both classes and call obj.wait() and obj.notifyAll(). It will work.

Below is one sample program. Basically there needs some common lock between 2 threads if you want communication using wait & notify.
package ravi.tutorial.java.threads;
public class TestThreads {
/**
* #param args
*/
public static void main(String[] args) {
CommonLock commonLock = new CommonLock();
Thread1 thread1 = new Thread1(commonLock);
Thread2 thread2 = new Thread2(commonLock);
thread1.start();
thread2.start();
}
}
/*
* Common monitor lock between both threads, used for communication using wait
* notify.
*/
class CommonLock {
}
// Extending Thread instead of Runnable as its just a test
class Thread1 extends Thread {
private CommonLock commonLock;
public Thread1(CommonLock commonLock) {
this.commonLock = commonLock;
}
public void run() {
System.out.println("Started thread 1");
System.out.println("waiting thread 1");
try {
// TO wait on commonLock, first need to get lock on commonLock. SO
// put synchronized block of commonLock.
synchronized (commonLock) {
commonLock.wait();
}
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("DONE waiting thread 1 as I got notification from THread 2");
}
}
class Thread2 extends Thread {
private CommonLock commonLock;
public Thread2(CommonLock commonLock) {
this.commonLock = commonLock;
}
public void run() {
System.out.println("Running thread 2");
try {
System.out.println("Sleeping thread 2");
// Just take gap of 2 sec before notifying.
Thread.sleep(2000);
// TO notify on commonLock, first need to get lock on commonLock. SO
// put synchronized block of commonLock.
synchronized (commonLock) {
System.out.println("Notifying thread 2");
commonLock.notifyAll();
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

Look at this: Thread tutorial
wait( ) tells the calling thread to give up the monitor and go to
sleep until some other thread enters the same monitor and calls
notify( ).
notify( ) wakes up the first thread that called wait( ) on
the same object.
notifyAll( ) wakes up all the threads that called wait( ) on the
same object. The highest priority thread will run first.
This is main misunderstanding of thread conception in Java.

Server and Client using Sockets

Are there any examples of a server and a client that use sockets, but that have send and get methods? I'm doing this networked battleship program, almost finished, but can't get the server and clients to work. I have made a chat program that only sends strings, but this time I need to send objects. I'm already frustrated, so is there any source code that already has this.
Here's the code for the client... how would you modify it to allow to send objects? Also I need to be listening for incoming objects and process them right away.
import java.net.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SimpleChat extends JFrame {
private Socket communicationSocket = null;
private PrintWriter outStream = null;
private BufferedReader inStream = null;
private Boolean communicationContinue = true;
private String disconnectString = "disconnect764*#$1";
private JMenuItem disconnectItem;
private JTextField displayLabel;
private final Color colorValues[] = { Color.black, Color.blue, Color.red, Color.green };
// set up GUI
public SimpleChat() {
super("Simple Chat");
// set up File menu and its menu items
JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic('F');
// set up Activate Server menu item
JMenuItem serverItem = new JMenuItem("Activate Server");
serverItem.setMnemonic('S');
fileMenu.add(serverItem);
serverItem.addActionListener(new ActionListener() { // anonymous inner class
// display message dialog when user selects About...
public void actionPerformed(ActionEvent event) {
setUpServer();
}
} // end anonymous inner class
); // end call to addActionListener
// set up Activate Client menu item
JMenuItem clientItem = new JMenuItem("Activate Client");
clientItem.setMnemonic('C');
fileMenu.add(clientItem);
clientItem.addActionListener(new ActionListener() { // anonymous inner class
// display message dialog when user selects About...
public void actionPerformed(ActionEvent event) {
setUpClient();
}
} // end anonymous inner class
); // end call to addActionListener
// set up Activate Client menu item
disconnectItem = new JMenuItem("Disconnect Client/Server");
disconnectItem.setMnemonic('D');
disconnectItem.setEnabled(false);
fileMenu.add(disconnectItem);
disconnectItem.addActionListener(new ActionListener() { // anonymous inner
// class
// display message dialog when user selects About...
public void actionPerformed(ActionEvent event) {
disconnectClientServer(true);
}
} // end anonymous inner class
); // end call to addActionListener
// set up About... menu item
JMenuItem aboutItem = new JMenuItem("About...");
aboutItem.setMnemonic('A');
fileMenu.add(aboutItem);
aboutItem.addActionListener(new ActionListener() { // anonymous inner class
// display message dialog when user selects About...
public void actionPerformed(ActionEvent event) {
JOptionPane.showMessageDialog(SimpleChat.this, "This is an example\nof using menus", "About",
JOptionPane.PLAIN_MESSAGE);
}
} // end anonymous inner class
); // end call to addActionListener
// set up Exit menu item
JMenuItem exitItem = new JMenuItem("Exit");
exitItem.setMnemonic('x');
fileMenu.add(exitItem);
exitItem.addActionListener(new ActionListener() { // anonymous inner class
// terminate application when user clicks exitItem
public void actionPerformed(ActionEvent event) {
disconnectClientServer(true);
System.exit(0);
}
} // end anonymous inner class
); // end call to addActionListener
// create menu bar and attach it to MenuTest window
JMenuBar bar = new JMenuBar();
setJMenuBar(bar);
bar.add(fileMenu);
// set up label to display text
displayLabel = new JTextField("Sample Text", SwingConstants.CENTER);
displayLabel.setForeground(colorValues[0]);
displayLabel.setFont(new Font("Serif", Font.PLAIN, 72));
displayLabel.addActionListener(new ActionListener() { // anonymous inner
// class
// display message dialog when user selects About...
public void actionPerformed(ActionEvent event) {
sendData();
}
} // end anonymous inner class
); // end call to addActionListener
getContentPane().setBackground(Color.CYAN);
getContentPane().add(displayLabel, BorderLayout.CENTER);
setSize(500, 200);
setVisible(true);
} // end constructor
public static void main(String args[]) {
final SimpleChat application = new SimpleChat();
application.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
application.disconnectClientServer(true);
System.exit(0);
}
});
// application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
}
public void setCommunicationSocket(Socket sock) {
communicationSocket = sock;
communicationContinue = true;
disconnectItem.setEnabled(true);
}
public void setOutStream(PrintWriter out) {
outStream = out;
}
public void setInStream(BufferedReader in) {
inStream = in;
}
public void setUpServer() {
ServerThread st = new ServerThread(this);
st.start();
}
public void setUpClient() {
ClientThread st = new ClientThread(this);
st.start();
}
public void disconnectClientServer(Boolean sendMessage) {
if (communicationSocket == null)
return;
try {
// shut down socket read loop
communicationContinue = false;
disconnectItem.setEnabled(false);
// send notification to other end of socket
if (sendMessage == true)
outStream.println(disconnectString);
// sleep to let read loop shut down
Thread t = Thread.currentThread();
try {
t.sleep(500);
} catch (InterruptedException ie) {
return;
}
outStream.close();
inStream.close();
communicationSocket.close();
} catch (IOException e) {
System.err.println("Stream Read Failed.");
JOptionPane.showMessageDialog(SimpleChat.this, "Disconnection Failed", "SimpleChat", JOptionPane.PLAIN_MESSAGE);
return;
} finally {
communicationSocket = null;
}
}
public void sendData() {
if (communicationSocket != null) {
String data = displayLabel.getText();
outStream.println(data);
}
}
public void getData() {
String inputLine;
try {
while (communicationContinue == true) {
communicationSocket.setSoTimeout(100);
// System.out.println ("Waiting for Connection");
try {
while (((inputLine = inStream.readLine()) != null)) {
System.out.println("From socket: " + inputLine);
if (inputLine.equals(disconnectString)) {
disconnectClientServer(false);
return;
}
displayLabel.setText(inputLine);
}
} catch (SocketTimeoutException ste) {
// System.out.println ("Timeout Occurred");
}
} // end of while loop
System.out.println("communication is false");
} catch (IOException e) {
System.err.println("Stream Read Failed.");
JOptionPane.showMessageDialog(SimpleChat.this, "Input Stream read failed", "SimpleChat",
JOptionPane.PLAIN_MESSAGE);
return;
}
}
}
class ServerThread extends Thread {
private SimpleChat sc;
private JTextField display;
public ServerThread(SimpleChat scParam) {
sc = scParam;
}
public void run() {
ServerSocket connectionSocket = null;
try {
connectionSocket = new ServerSocket(10007);
} catch (IOException e) {
System.err.println("Could not listen on port: 10007.");
JOptionPane.showMessageDialog(sc, "Could not listen on port: 10007", "Server", JOptionPane.PLAIN_MESSAGE);
return;
}
JOptionPane.showMessageDialog(sc, "Server Socket is now activated", "Server", JOptionPane.PLAIN_MESSAGE);
Socket communicationSocket = null;
try {
communicationSocket = connectionSocket.accept();
} catch (IOException e) {
System.err.println("Accept failed.");
JOptionPane.showMessageDialog(sc, "Accept failed", "Server", JOptionPane.PLAIN_MESSAGE);
return;
}
JOptionPane.showMessageDialog(sc, "Comminucation is now activated", "Server", JOptionPane.PLAIN_MESSAGE);
try {
PrintWriter out = new PrintWriter(communicationSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(new InputStreamReader(communicationSocket.getInputStream()));
sc.setCommunicationSocket(communicationSocket);
sc.setOutStream(out);
sc.setInStream(in);
connectionSocket.close();
sc.getData();
} catch (IOException e) {
System.err.println("Accept failed.");
JOptionPane.showMessageDialog(sc, "Creation of Input//Output Streams failed", "Server", JOptionPane.PLAIN_MESSAGE);
return;
}
}
}
class ClientThread extends Thread {
private SimpleChat sc;
public ClientThread(SimpleChat scParam) {
sc = scParam;
}
public void run() {
Socket echoSocket = null;
PrintWriter out = null;
BufferedReader in = null;
String ipAddress = "127.0.0.1";
try {
echoSocket = new Socket(ipAddress, 10007);
out = new PrintWriter(echoSocket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(echoSocket.getInputStream()));
} catch (UnknownHostException e) {
System.err.println("Don't know about host: " + ipAddress);
JOptionPane.showMessageDialog(sc, "Don't know about host: " + ipAddress, "Client", JOptionPane.PLAIN_MESSAGE);
return;
} catch (IOException e) {
System.err.println("Couldn't get I/O for " + "the connection to: " + ipAddress);
JOptionPane.showMessageDialog(sc, "Couldn't get I/O for the connection to: " + ipAddress, "Client",
JOptionPane.PLAIN_MESSAGE);
return;
}
JOptionPane.showMessageDialog(sc, "Comminucation is now activated", "Client", JOptionPane.PLAIN_MESSAGE);
sc.setCommunicationSocket(echoSocket);
sc.setOutStream(out);
sc.setInStream(in);
sc.getData();
}
}

I suggest you read up on java serialization. There is an example here. Basically, there is built in serialization support. Your class needs to implement Serializable. Then you use ObjectOutputStream and ObjectInputStream to write object.

You would be well advised to use libraries that shield you from the error prone low level socket programming.
For C++ look to Boost (http://www.boost.com) or ACE (http://www.cs.wustl.edu/~schmidt/ACE.html)
For Java I only found a document that talks about the acceptor pattern http://www.hillside.net/plop/plop99/proceedings/Fernandez3/RACPattern.PDF
But I am sure there's an implementation out somewhere

Your on the right track. A chat program is a good place to start learning about sockets.
What you want is to use the ObjectOutputStream and ObjectInputStream classes. You simply have to wrap your input stream / output stream with these filters. ObjectOutputStream has a method writeObject(), and the ObjectInputStream has a corresponding readObject() method.
Most serialization examples show reading and writing objects to a file, but the same can be done using a socket stream. See http://www.acm.org/crossroads/xrds4-2/serial.html

I didn't bother to read through your piles and piles of code, but in general you can't directly send objects over the network. Network communication is just bits and bytes. If you want to send objects, you'll need to serialize them on the sending side, and de-serialize them on the receiving side. There are tons of methods of serializing, eg JSON, XML, or even Java's built-in serialization support (only recommended if both the client and server will always be Java).

You may find this code to be a decent starting point for making your own class. These are two classes I made to somewhat abstract the work needed for TCP and UDP socket protocols:
http://code.google.com/p/hivewars/source/browse/trunk/SocketData.java
http://code.google.com/p/hivewars/source/browse/trunk/UDPSocket.java
Quick dislaimer: These are kind of versions of a feature full class, I just added functionality as I needed it. However, it could help you start.