ClientGUI.java

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.SystemColor;
import javax.swing.ButtonGroup;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JRadioButton;
import javax.swing.SwingUtilities;
import java.awt.Toolkit;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.io.EOFException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;

public class ClientGUI extends JFrame {

    private static final long serialVersionUID = 1L;
    private JFrame frame;
    private JTextField enterField;
    private JTextField txtServerIP;
    private JTextField txtServerPort;
    private JTextArea displayArea;
    public String clientNick = "";

    private ObjectOutputStream output;
    private ObjectInputStream input;
    private String message = "";
    private String chatServer;
    private Socket client;

    private final ButtonGroup buttonGroup = new ButtonGroup();

    /**
     * Launch the application.
     */

    public ClientGUI(String host) {
        super("Client Interface");
        chatServer = host;
        initialize();

    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setIconImage(Toolkit
                .getDefaultToolkit()
                .getImage(
                        ClientGUI.class
                                .getResource("/com/sun/java/swing/plaf/windows/icons/Computer.gif")));
        frame.setBounds(100, 100, 640, 589);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JPanel panel1 = new JPanel();
        panel1.setBackground(SystemColor.inactiveCaptionBorder);
        panel1.setBounds(10, 11, 604, 100);
        frame.getContentPane().add(panel1);
        panel1.setLayout(null);




        JLabel lblServerIP = new JLabel("Server IP");
        lblServerIP.setBounds(10, 39, 60, 14);
        panel1.add(lblServerIP);

        txtServerIP = new JTextField();
        txtServerIP.setText("127.0.0.1");
        txtServerIP.setBounds(73, 36, 160, 20);
        panel1.add(txtServerIP);
        txtServerIP.setColumns(10);

        JLabel lblServerPort = new JLabel("Server Port");
        lblServerPort.setBounds(10, 64, 60, 14);
        panel1.add(lblServerPort);

        txtServerPort = new JTextField();
        txtServerPort.setText("14789");
        txtServerPort.setBounds(73, 61, 160, 20);
        panel1.add(txtServerPort);
        txtServerPort.setColumns(10);

        JRadioButton rdbtnTcp = new JRadioButton("TCP");
        rdbtnTcp.setSelected(true);
        rdbtnTcp.setBackground(SystemColor.inactiveCaptionBorder);
        buttonGroup.add(rdbtnTcp);
        rdbtnTcp.setBounds(260, 30, 60, 23);
        panel1.add(rdbtnTcp);

        JRadioButton rdbtnUdp = new JRadioButton("UDP");
        rdbtnUdp.setBackground(SystemColor.inactiveCaptionBorder);
        buttonGroup.add(rdbtnUdp);
        rdbtnUdp.setBounds(260, 55, 53, 23);
        panel1.add(rdbtnUdp);

        JLabel lblProtocol = new JLabel("Protocol");
        lblProtocol.setBounds(260, 14, 46, 14);
        panel1.add(lblProtocol);

        JButton btnConnect = new JButton("Connect to Server");
        btnConnect.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
            }
        });
        btnConnect.setBounds(326, 11, 109, 30);
        panel1.add(btnConnect);

        JPanel panel2 = new JPanel();
        panel2.setBackground(SystemColor.info);
        panel2.setBounds(10, 122, 604, 418);
        frame.getContentPane().add(panel2);
        panel2.setLayout(null);

        enterField = new JTextField();
        enterField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                sendData(e.getActionCommand());
                enterField.setText("");
            }
        });
        enterField.setBounds(10, 372, 584, 35);
        panel2.add(enterField);
        enterField.setColumns(10);

        JTextArea displayArea = new JTextArea();
        displayArea.setEditable(false);
        displayArea.setBounds(10, 11, 584, 350);
        panel2.add(displayArea);
    }

    // public static String istemciNick = "CLIENT";

    private void connectToServer() throws IOException {
        displayMessage("Connecting...");

        client = new Socket(txtServerIP.getText(),
                Integer.parseInt(txtServerPort.getText()));

        // display connection information
        displayMessage("Connected to "
                + client.getInetAddress().getHostName());
    }

    // get streams to send and receive data
    private void getStreams() throws IOException {
        // set up output stream for objects
        output = new ObjectOutputStream(client.getOutputStream());
        output.flush(); // flush output buffer to send header information

        // set up input stream for objects
        input = new ObjectInputStream(client.getInputStream());

        displayMessage("Got I/O stream.");
    }

    // process connection with server
    private void processConnection() throws IOException {
        // enable enterField so client user can send messages
        setTextFieldEditable(true);

        do { // process messages sent from server

            // read message and display it
            try {
                message = (String) input.readObject();
                displayMessage(message);
            }

            // catch problems reading from server
            catch (ClassNotFoundException classNotFoundException) {
                displayMessage("Unknown object type receieved.");
            }

        } while (!message.contains("TERMINATE"));

    } // end method processConnection

    // close streams and socket
    private void closeConnection() {
        displayMessage("Closing connection...");
        setTextFieldEditable(false); // disable enterField

        try {
            output.close();
            input.close();
            client.close();
            displayMessage("Connection closed...");

        } catch (IOException ioException) {
            ioException.printStackTrace();
        }
    }

    // send message to server
    private void sendData(String message) {
        // send object to server
        try {
            output.writeObject("Client > " + message);
            output.flush();
            displayMessage("Client > " + message);
        }
        // process problems sending object
        catch (IOException ioException) {
            displayArea.append("Error writing object.");
        }
    }

    // utility method called from other threads to manipulate
    // displayArea in the event-dispatch thread
    private void displayMessage(final String messageToDisplay) {
        // display message from GUI thread of execution
        SwingUtilities.invokeLater(new Runnable() { //inner class to ensure GUI updates properly

                    public void run() // updates displayArea
                    {
                        displayArea.append("\n" + messageToDisplay);
                        displayArea.setCaretPosition(displayArea.getText()
                                .length());
                    }

                } // end inner class

                ); // end call to SwingUtilities.invokeLater
    }

    // utility method called from other threads to manipulate
    // enterField in the event-dispatch thread
    private void setTextFieldEditable(final boolean editable) {
        // display message from GUI thread of execution
        SwingUtilities.invokeLater(new Runnable() { // inner class to ensure
                    // GUI
                    // // updates properly
                    //
                    public void run() // sets enterField's editability
                    {
                        enterField.setEditable(editable);
                    }
                    //
                } // end inner class
                    //
                ); // end call to SwingUtilities.invokeLater
    }

    // connect to server and process messages from server
    private void runClient() {
        // connect to server, get streams, process connection
        try {
            connectToServer(); // Step 1: Create a Socket to make connection
            getStreams(); // Step 2: Get the input and output streams
            processConnection(); // Step 3: Process connection
        }
        // server closed connection
        catch (EOFException eofException) {
            System.err.println("Server terminated connection.");
        }
        // process problems communicating with server
        catch (IOException ioException) {
            ioException.printStackTrace();
        } finally {
            closeConnection(); // Step 4: Close connection
        }
    } // end method runClient

    public static void main(String[] args) {
        ClientGUI application;

        if (args.length == 0)
            application = new ClientGUI("127.0.0.1");
        else
            application = new ClientGUI(args[0]);

        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        application.runClient();

    }

}