Java - Chatting Room ( GUI server)

// Client.java
package chatRoom;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.border.TitledBorder;

public class Client {

    private JFrame frame;
    private JList userList;
    private JTextArea textArea;
    private JTextField textField;
    private JTextField txt_port;
    private JTextField txt_hostIp;
    private JTextField txt_name;
    private JButton btn_start;
    private JButton btn_stop;
    private JButton btn_send;
    private JPanel northPanel;
    private JPanel southPanel;
    private JScrollPane rightScroll;
    private JScrollPane leftScroll;
    private JSplitPane centerSplit;

    private DefaultListModel listModel;

    private boolean isConnected = false;

    private Socket socket;
    private PrintWriter out;
    private BufferedReader in;
    private ReceiveMessage receiveMessage;
    //private Map<String, User> onLineUsers = new HashMap<String, User>();

    public Client() {

        init();

        btn_start.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                int port;
                if (isConnected) {
                    JOptionPane.showMessageDialog(frame, "isConnected",
                            "", JOptionPane.ERROR_MESSAGE);
                    return;
                }
                try {
                    try {
                        port = Integer.parseInt(txt_port.getText().trim());
                    } catch (NumberFormatException e2) {
                        throw new Exception("Port error");
                    }

                    String hostIp = txt_hostIp.getText().trim();

                    String name = txt_name.getText().trim();

                    if (name.equals("") || hostIp.equals("")) {
                        throw new Exception("No Login");
                    }

                    // ====> connect to server
                    boolean flag = connectServer(port, hostIp, name);

                    if (flag == false) {
                        throw new Exception("Connection error");
                    }

                    frame.setTitle(name);
                    JOptionPane.showMessageDialog(frame, "Welcome " + name);

                } catch (Exception exc) {
                    JOptionPane.showMessageDialog(frame, exc.getMessage(),
                            "", JOptionPane.ERROR_MESSAGE);
                }
            }
        });

        btn_stop.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (!isConnected) {
                    JOptionPane.showMessageDialog(frame, "Is not connected!",
                            "", JOptionPane.ERROR_MESSAGE);
                    return;
                }
                try {

                    // close connection to server
                    boolean flag = closeConnection();

                    if (flag == false) {
                        throw new Exception("Close error");
                    }

                    JOptionPane.showMessageDialog(frame, "I am leaving.");

                } catch (Exception exc) {
                    JOptionPane.showMessageDialog(frame, exc.getMessage(),
                            "", JOptionPane.ERROR_MESSAGE);
                }
            }
        });

        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                if (isConnected) {

                    // close connection to server
                    closeConnection();
                }
                System.exit(0);
            }
        });

        textField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                send();
            }
        });

        btn_send.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                send();
            }
        });

    }  // end of Client

    public void init() {

        textArea = new JTextArea();
        textArea.setEditable(false);
        textArea.setForeground(Color.blue);
        textField = new JTextField();
        txt_port = new JTextField("6666");
        txt_hostIp = new JTextField("127.0.0.1");
        txt_name = new JTextField("");
        btn_start = new JButton("Start");
        btn_stop = new JButton("Stop");
        btn_send = new JButton("Send");
        listModel = new DefaultListModel();
        userList = new JList(listModel);

        northPanel = new JPanel();
        northPanel.setLayout(new GridLayout(1, 7));
        northPanel.add(new JLabel("Port"));
        northPanel.add(txt_port);
        northPanel.add(new JLabel("IP"));
        northPanel.add(txt_hostIp);
        northPanel.add(new JLabel("Login"));
        northPanel.add(txt_name);
        northPanel.add(btn_start);
        northPanel.add(btn_stop);
        northPanel.setBorder(new TitledBorder(""));

        rightScroll = new JScrollPane(textArea);
        rightScroll.setBorder(new TitledBorder(""));
        leftScroll = new JScrollPane(userList);
        leftScroll.setBorder(new TitledBorder(""));
        southPanel = new JPanel(new BorderLayout());
        southPanel.add(textField, "Center");
        southPanel.add(btn_send, "East");
        southPanel.setBorder(new TitledBorder(""));

        centerSplit = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftScroll,
                rightScroll);
        centerSplit.setDividerLocation(100);

        frame = new JFrame("");
        //frame.setIconImage(Toolkit.getDefaultToolkit().createImage(Client.class.getResource("qq.png")));
        frame.setLayout(new BorderLayout());
        frame.add(northPanel, "North");
        frame.add(centerSplit, "Center");
        frame.add(southPanel, "South");
        frame.setSize(600, 400);
        int screen_width = Toolkit.getDefaultToolkit().getScreenSize().width;
        int screen_height = Toolkit.getDefaultToolkit().getScreenSize().height;
        frame.setLocation((screen_width - frame.getWidth()) / 2,
                (screen_height - frame.getHeight()) / 2);
        frame.setVisible(true);
    }

    //LOGIN
    public boolean connectServer(int port, String hostIp, String name) {

        try {
            socket = new Socket(hostIp, port);
            out = new PrintWriter(socket.getOutputStream());
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            //LOGIN
            // name@/x.x.x.x
            sendMessage(name + "@" + socket.getLocalAddress().toString());

            //receive message
            //receiveMessage = new ReceiveMessage(in, textArea);
            receiveMessage = new ReceiveMessage();
            receiveMessage.start();

            isConnected = true;
            return true;

        } catch (Exception e) {
            textArea.append("Server port: " + port + "Server IP: " + hostIp + "\r\n");
            isConnected = false;
            return false;
        }
    }

    @SuppressWarnings("deprecation")
    public synchronized boolean closeConnection() {
        try {

            sendMessage("CLOSE");
            receiveMessage.stop(); //NullPointerException

            if (in != null) { in.close(); }
            if (out != null) { out.close(); }
            if (socket != null) { socket.close(); }

            isConnected = false;
            return true;

        } catch (IOException e1) {
            e1.printStackTrace();
            isConnected = true;
            return false;
        }
    }

    public void send() {
        if (!isConnected) {
            JOptionPane.showMessageDialog(frame, "Is not connected!", "",
                    JOptionPane.ERROR_MESSAGE);
            return;
        }

        String message = textField.getText().trim();

        if (message == null || message.equals("")) {
            JOptionPane.showMessageDialog(frame, "No message", "",
                    JOptionPane.ERROR_MESSAGE);
            return;
        }

        // username@ALL@hello world
        sendMessage(frame.getTitle() + "@" + "ALL" + "@" + message);

        textField.setText(null);
    }

    public void sendMessage(String message) {

        out.println(message);
        out.flush();
    }

    class ReceiveMessage extends Thread {

        public void run() {
            String msgFromServer = "";
            while (true) {
                try {

                    // => CLOSE, ADD@, DELETE@, USERLIST@, MAX@, or username: hi
                    msgFromServer = in.readLine();
                    System.out.println(msgFromServer);

                    // '/' or, '@'
                    StringTokenizer tok = new StringTokenizer(msgFromServer, "/@");

                    String command = tok.nextToken();

                    // CLOSE
                    if (command.equals("CLOSE")) {
                        textArea.append("Server closed!\r\n");
                        removeUsers();
                        return;

                    // MAX@username/x.x.x.x
                    } else if (command.equals("MAX")) {
                        textArea.append("Max limited!\r\n");
                        removeUsers();
                        return;

                    // DELETE@username
                    } else if (command.equals("DELETE")) {

                        String username = tok.nextToken();

                        listModel.removeElement(username);

                    // ADD@username/x.x.x.x
                    } else if (command.equals("ADD")) {

                        String username = "";
                        String userIp = "";

                        if ((username = tok.nextToken()) != null
                                && (userIp = tok.nextToken()) != null) {

                            listModel.addElement(username);
                        }

                    // USERLIST@numOfUser@username@/x.x.x.x@username@/x.x.x.x
                    } else if (command.equals("USERLIST")) {

                        int numOfUser = Integer.parseInt(tok.nextToken());
                        String username = null;
                        String userIp = null;

                        for (int i = 0; i < numOfUser; i++) {
                            username = tok.nextToken();
                            userIp = tok.nextToken();

                            listModel.addElement(username);
                        }

                    // username: hello world
                    } else {
                        textArea.append(msgFromServer + "\r\n");
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }

        public synchronized void removeUsers() throws Exception {

            listModel.removeAllElements();

            if (in != null) { in.close(); }
            if (out != null) { out.close(); }
            if (socket != null) { socket.close(); }
            isConnected = false;
        }
    }
    public static void main(String[] args) {
        new Client();
    }
}


// Server.java
package chatRoom;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.StringTokenizer;

import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.border.TitledBorder;

public class Server {

    private JFrame frame;
    JTextArea contentArea;
    private JTextField txt_message;
    private JTextField txt_max;
    private JTextField txt_port;
    private JButton btn_start;
    private JButton btn_stop;
    private JButton btn_send;
    private JPanel northPanel;
    private JPanel southPanel;
    private JScrollPane rightPanel;
    private JScrollPane leftPanel;
    private JSplitPane centerSplit;
    private JList userList;
    DefaultListModel listModel;

    private ServerSocket serverSocket;
    private ServerConnect serverConnect;
    ArrayList<NewClient> clientArray = new ArrayList<NewClient>();

    String loginName = "";
    String loginIP = "";

    private boolean isStart = false;

    public Server() {

        init();

        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                if (isStart) {
                    closeServer();
                }
                System.exit(0);
            }
        });

        txt_message.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                send();
            }
        });

        btn_send.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                send();
            }
        });

        btn_start.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (isStart) {
                    JOptionPane.showMessageDialog(frame, "Already started",
                            "", JOptionPane.ERROR_MESSAGE);
                    return;
                }
                int max;
                int port;
                try {
                    try {
                        max = Integer.parseInt(txt_max.getText());
                    } catch (Exception e1) {
                        throw new Exception("max error");
                    }
                    if (max <= 0) {
                        throw new Exception("max is null");
                    }
                    try {
                        port = Integer.parseInt(txt_port.getText());
                    } catch (Exception e1) {
                        throw new Exception("port error");
                    }
                    if (port <= 0) {
                        throw new Exception("port is null");
                    }

                    serverStart(max, port);

                    contentArea.append("max is " + max + ", port is " + port
                            + "\r\n");

                    JOptionPane.showMessageDialog(frame, "Started!");

                    btn_start.setEnabled(false);
                    txt_max.setEnabled(false);
                    txt_port.setEnabled(false);
                    btn_stop.setEnabled(true);

                } catch (Exception exc) {
                    JOptionPane.showMessageDialog(frame, exc.getMessage(),
                            "", JOptionPane.ERROR_MESSAGE);
                }
            }
        });

        btn_stop.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (!isStart) {
                    JOptionPane.showMessageDialog(frame, "Not started!", "",
                            JOptionPane.ERROR_MESSAGE);
                    return;
                }
                try {

                    closeServer();

                    btn_start.setEnabled(true);
                    txt_max.setEnabled(true);
                    txt_port.setEnabled(true);
                    btn_stop.setEnabled(false);
                    contentArea.append("Closed!\r\n");
                    JOptionPane.showMessageDialog(frame, "Closed!");
                } catch (Exception exc) {
                    JOptionPane.showMessageDialog(frame, "Closing error!", "",
                            JOptionPane.ERROR_MESSAGE);
                }
            }
        });
    }

    public void init() {
        frame = new JFrame("");
        //frame.setIconImage(Toolkit.getDefaultToolkit().createImage(Client.class.getResource("qq.png")));
        //frame.setIconImage(Toolkit.getDefaultToolkit().createImage(Server.class.getResource("qq.png")));
        contentArea = new JTextArea();
        contentArea.setEditable(false);
        contentArea.setForeground(Color.blue);
        txt_message = new JTextField();
        txt_max = new JTextField("30");
        txt_port = new JTextField("6666");
        btn_start = new JButton("Start");
        btn_stop = new JButton("Stop");
        btn_send = new JButton("Send");
        btn_stop.setEnabled(false);
        listModel = new DefaultListModel();
        userList = new JList(listModel);

        southPanel = new JPanel(new BorderLayout());
        southPanel.setBorder(new TitledBorder(""));
        southPanel.add(txt_message, "Center");
        southPanel.add(btn_send, "East");
        leftPanel = new JScrollPane(userList);
        leftPanel.setBorder(new TitledBorder(""));

        rightPanel = new JScrollPane(contentArea);
        rightPanel.setBorder(new TitledBorder(""));

        centerSplit = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftPanel,
                rightPanel);
        centerSplit.setDividerLocation(100);
        northPanel = new JPanel();
        northPanel.setLayout(new GridLayout(1, 6));
        northPanel.add(new JLabel("Max of chatter"));
        northPanel.add(txt_max);
        northPanel.add(new JLabel("Port"));
        northPanel.add(txt_port);
        northPanel.add(btn_start);
        northPanel.add(btn_stop);
        northPanel.setBorder(new TitledBorder(""));

        frame.setLayout(new BorderLayout());
        frame.add(northPanel, "North");
        frame.add(centerSplit, "Center");
        frame.add(southPanel, "South");
        frame.setSize(600, 400);
        //frame.setSize(Toolkit.getDefaultToolkit().getScreenSize());
        int screen_width = Toolkit.getDefaultToolkit().getScreenSize().width;
        int screen_height = Toolkit.getDefaultToolkit().getScreenSize().height;
        frame.setLocation((screen_width - frame.getWidth()) / 2,
                (screen_height - frame.getHeight()) / 2);
        frame.setVisible(true);
    }

    public void serverStart(int max, int port) throws java.net.BindException {
        try {

            serverSocket = new ServerSocket(port);

            serverConnect = new ServerConnect(this, serverSocket, max);
            serverConnect.start();

            isStart = true;

        } catch (BindException e) {
            isStart = false;
            throw new BindException("Server is already connected");
        } catch (Exception e1) {
            e1.printStackTrace();
            isStart = false;
            throw new BindException("Bind Exception");
        }
    }

    @SuppressWarnings("deprecation")
    public void closeServer() {
        try {
            if (serverConnect != null) {
                serverConnect.stop();  //SocketException: Socket closed
            }
            for (int i = clientArray.size() - 1; i >= 0; i--) {

                clientArray.get(i).sendToMe("CLOSE");
                //guestArray.get(i).getWriter().flush();

                clientArray.get(i).stop(); // Exception
                clientArray.get(i).in.close();
                clientArray.get(i).out.close();
                clientArray.get(i).clientSocket.close();
                clientArray.remove(i);
            }
            if (serverSocket != null) {
                serverSocket.close();
            }
            listModel.removeAllElements();
            isStart = false;
        } catch (IOException e) {
            e.printStackTrace();
            isStart = true;
        }
    }

    public void send() {
        if (!isStart) {
            JOptionPane.showMessageDialog(frame, "Server is not working", "Warning",
                    JOptionPane.ERROR_MESSAGE);
            return;
        }
        if (clientArray.size() == 0) {
            JOptionPane.showMessageDialog(frame, "No client", "Warning",
                    JOptionPane.ERROR_MESSAGE);
            return;
        }
        String message = txt_message.getText().trim();
        if (message == null || message.equals("")) {
            JOptionPane.showMessageDialog(frame, "No message", "Warning",
                    JOptionPane.ERROR_MESSAGE);
            return;
        }
        sendServerMessage(message);

        contentArea.append("Server: " + txt_message.getText() + "\r\n");
        txt_message.setText(null);
    }

    public void sendServerMessage(String message) {
        for (NewClient newClient : clientArray) {
            newClient.sendToMe("Server: " + message);
        }
    }

    class ServerConnect extends Thread {

        private ServerSocket serverSocket;
        private int max;
        private Server server;

        public ServerConnect(Server server, ServerSocket serverSocket, int max) {
            this.server = server;
            this.serverSocket = serverSocket;
            this.max = max;
        }

        public void run() {
            while (true) {
                try {
                    Socket clientSocket = serverSocket.accept();

                    if (clientArray.size() == max) {

                        BufferedReader in = new BufferedReader(
                                new InputStreamReader(clientSocket.getInputStream()));
                        PrintWriter out = new PrintWriter(clientSocket.getOutputStream());

                        String infoUser = in.readLine();
                        // userName/127.0.0.1
                        StringTokenizer tok = new StringTokenizer(infoUser, "@");
                        //user = new ServerUser(tok.nextToken(), tok.nextToken());

                        loginName = tok.nextToken();
                        loginIP = tok.nextToken();

                        //send to limited user
                        out.println("MAX@" + loginName + loginIP);
                        out.flush();

                        in.close();
                        out.close();
                        clientSocket.close();
                        continue;
                    }

                    NewClient newClient = new NewClient(server, clientSocket);

                    newClient.start(); // receiving message from client

                    // clientArray will be added after receiving message from client
                    clientArray.add(newClient);

                    listModel.addElement(newClient.getUserName());

                    contentArea.append("Joined: " + newClient.getUserName()
                            + newClient.getUserIP() + "\r\n");

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }  // end of ServerConnect class

    public static void main(String[] args) {
        new Server();
    }
}


// NewClient.java
package chatRoom;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.StringTokenizer;

public class NewClient extends Thread {

    Socket clientSocket;
    Server server;

    BufferedReader in;
    PrintWriter out;

    String loginName = "";
    String loginIP = "";

    // LOGIN
    public NewClient(Server server, Socket clientSocket) throws IOException {

        this.server = server;
        this.clientSocket = clientSocket;

        in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        out = new PrintWriter(clientSocket.getOutputStream());

        String loginInfo = in.readLine();
        // userName@/127.0.0.1 => (userName, userIP)
        StringTokenizer tok = new StringTokenizer(loginInfo, "@");

        loginName = tok.nextToken();
        loginIP = tok.nextToken();

        sendToMe("Welcome " + loginName + loginIP);

        // ==> send the list of chatters to clients <==
        // clientArray is not added in the beginning
        // is added after run()
        // new user
        if (server.clientArray.size() > 0) {
            String temp = "";
            for (NewClient newClient : server.clientArray) {
                temp += (newClient.loginName + newClient.loginIP) + "@";
            }
            // send other's login info to me
            sendToMe("USERLIST@" + server.clientArray.size() + "@" + temp);
        }

        // old user
        for (NewClient newClient : server.clientArray) {
            // send my login info to other
            newClient.sendToMe("ADD@" + loginName + loginIP);
        }
    }

    // RECEIVING MESSAGE
    public void run() {
        String msgFromClient = null;
        while (true) {
            try {
                // msgFromClient = username@ALL@hello world
                msgFromClient = in.readLine();

                if (msgFromClient.equals("CLOSE")) {

                    server.contentArea.append("Left: " + loginName + loginIP + "\r\n");

                    in.close();
                    out.close();
                    clientSocket.close();

                    for (NewClient newClient : server.clientArray) {
                        newClient.sendToMe("DELETE@" + loginName);
                    }

                    server.listModel.removeElement(loginName);

                    server.clientArray.remove(this);

                    return;  // error without "return"

                } else {

                    // msgFromClient = username@ALL@hello world
                    StringTokenizer tok = new StringTokenizer(msgFromClient, "@");

                    String sender = tok.nextToken();
                    String receiver = tok.nextToken();
                    String content = tok.nextToken();

                    for (NewClient newClient : server.clientArray) {
                        if (receiver.equals("ALL")) {
                            if (!sender.equals(newClient.getUserName())) {
                                msgFromClient = sender + ": " + content;
                                newClient.sendToMe(msgFromClient);
                            } else {
                                String msgFromMe = "Me" + ": " + content;
                                sendToMe(msgFromMe);
                                msgFromClient = sender + ": " + content;
                            }
                        }
                    }
                    server.contentArea.append(msgFromClient + "\r\n");
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public void sendToMe(String msg) {
        out.println(msg);
        out.flush();
    }

    public String getUserName() {
        return loginName;
    }

    public String getUserIP() {
        return loginIP;
    }
}