Client GUI

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class GUIForClient extends JFrame implements ActionListener
{
    private JLabel label, label2;
    private JTextField jtfMessage, jtfServer, jtfPort;
    private JButton connect, exit;
    private JTextArea jtaSouth;
    private boolean isConnected;
    private Client client;
    private int initialPort;
    private String initialHost;

    /**
     * Constructor for objects of class GUIForClient
     */
    public GUIForClient(String host, int port)
    {
        super("Messaging Client");
        initialHost = host;
        initialPort = port;
        JPanel north = new JPanel(new GridLayout(3,1));
        JPanel serverPortPanel = new JPanel(new GridLayout(1,5,1,3));
        jtfServer = new JTextField(host);
        jtfPort = new JTextField(port);
        jtfPort.setHorizontalAlignment(SwingConstants.RIGHT);

        serverPortPanel.add(new JLabel("Name or IP Address of server: "));
        serverPortPanel.add(jtfServer);
        serverPortPanel.add(new JLabel("Connection on port: "));
        serverPortPanel.add(jtfPort);

        north.add(serverPortPanel);

        label = new JLabel("Please enter your name below.", SwingConstants.CENTER);
        north.add(label);
        jtfMessage = new JTextField();
        north.add(jtfMessage);
        add(north, BorderLayout.NORTH);

        jtaSouth = new JTextArea("Welcome!\n", 60, 50);
        JPanel center = new JPanel(new GridLayout(1,1));
        center.add(new JScrollPane(jtaSouth));
        jtaSouth.setEditable(false);
        add(center, BorderLayout.CENTER);

        connect = new JButton("Connect");
        connect.addActionListener(this);
        exit = new JButton("Exit");
        exit.addActionListener(this);
        JPanel south = new JPanel();
        south.add(connect);
        south.add(exit);
        add(south, BorderLayout.SOUTH);

        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(1200, 600);
        setVisible(true);
        jtfMessage.requestFocus();
    }

    public void appendStuff(String str)
    {
        jtaSouth.append(str);
        jtaSouth.setCaretPosition(jtaSouth.getText().length() - 1);
    }

    public void ifConnectionFails()
    {
        connect.setEnabled(true);
        exit.setEnabled(true);
        label.setText("Please enter your name below.");
        jtfMessage.setText(" ");
        jtfServer.setText("" + initialHost);
        jtfPort.setText("" + initialPort);

        jtfPort.setEditable(true);
        jtfServer.setEditable(true);

        jtfMessage.removeActionListener(this);
        isConnected = false;
    }

    public void actionPerformed(ActionEvent ae)
    {
        Object obj = ae.getSource();

        if(obj == exit)
        {
            client.sendMessage(new messageType(messageType.EXIT, ""));
            return;
        }

        if(isConnected)
        {
            client.sendMessage(new messageType(messageType.MESSAGE, jtfMessage.getText()));
            jtfMessage.setText("");
            return;
        }

        if(obj == connect)
        {
            String username = jtfMessage.getText().trim();

            if(username.length() == 0)
            {
                return;
            }

            String serverName = jtfServer.getText().trim();
            if(serverName.length() == 0)
            {
                return;
            }

            String portNumber = jtfPort.getText().trim();
            if(portNumber.length() == 0)
            {
                return;
            }

            int port = 0;
            try
            {
                port = Integer.parseInt(portNumber);
            }
            catch(Exception e)
            {
            }

            client = new Client(serverName, port, username, this);

            if(!client.start())
            {
                return;
            }

            jtfMessage.setText("");
            label.setText("Type your message below.");
            isConnected = true;

            connect.setEnabled(false);

            jtfServer.setEditable(false);
            jtfPort.setEditable(false);

            jtfMessage.addActionListener(this);
        }
    }

    public static void main(String[] args)
    {
        new GUIForClient("localhost", 7257);
    }
}