Client.java

import java.awt.*;
import javax.swing.*;
import javax.swing.border.Border;
import java.io.*;
import java.net.*;
import java.awt.event.*;

public class Client extends JFrame {
	
	private static final long serialVersionUID = 1L;
	private JTextField userText;
	private JTextArea chatWindow;
	private ObjectOutputStream output;
	private ObjectInputStream input;
	private Socket connection;
	private String message = "";
	private String serverIP;
	
	// constructor and the GUI
	// since we dont want everyone to access our computer
	// we want to make sure it just connects to host(so the ip address of the server)
	public Client(String host) {
		super("Client Side Instant Messenger");
		serverIP = host;
		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),BorderLayout.CENTER);
		setSize(700,400);
		setVisible(true);
		
	}
	
	
	
	// connect to server
	
	public void startRunning() {
		try {
			// we don't wanna wait for connection like server
			connectToServer();
			setupStreams();
			whileChatting();
		} catch (EOFException eofexception) {
			showMessage("\nClient terminated connection");
		}catch(IOException ioException) {
			ioException.printStackTrace();
		}finally {
			closeStuff();
		}
	}
	
	

	private void connectToServer() throws IOException {
		
		
		
		showMessage("Attempting Connection...\n");
		// we gotta know the port number of the host
		connection = new Socket(InetAddress.getByName(serverIP), 6789);
		showMessage("Connected to: "+connection.getInetAddress().getHostName());
	}

	
	// setup stream to send and receive messages
	
	private void setupStreams() throws IOException {
		output = new ObjectOutputStream(connection.getOutputStream());
		output.flush();
		input = new ObjectInputStream(connection.getInputStream());
		showMessage("\nStreams are now setup \n");
		
	}

	
     // while chatting with server
	private void whileChatting() throws IOException {
		ableToType(true);
		do {
			try {
				message = (String)input.readObject();
				showMessage("\n "+ message);
		
			} catch (ClassNotFoundException classNotFoundException) {
				// TODO: handle exception
				showMessage("\n I don't know that object type");
			}
		} while (!message.equals("MOZHGAN: END"));
		
	}
	
	
	// closing the streams and sockets

	private void closeStuff() {
	
		showMessage("\nClosing Streams and Sockets down...");
		ableToType(false);
		try {
			output.close();
			input.close();
			connection.close();
		} catch (IOException ioException) {
			// TODO: handle exception
			ioException.printStackTrace();
		}
	}

	
	// sending the messages to server
	
	private void sendMessage(String msg) {
		
		try {
			output.writeObject("MOZHGAN :"+ msg);
			output.flush();
			showMessage("\nMOZHGAN: "+msg);
			
			
		} catch (IOException ioException) {
			// TODO: handle exception
			chatWindow.append("\nCould not send the message successfully! ");
		}
	}
	
	

	// change/ update the chat area
	private void showMessage(final String m) {
		SwingUtilities.invokeLater(
				new Runnable() {
					public void run() {
						chatWindow.append(m);
					}
				}
				
			);
	}
	

	// gives user permission to type into the textbox
	
	private void ableToType(final boolean tof) {
		
		SwingUtilities.invokeLater(
				new Runnable() {
					public void run() {
						userText.setEditable(tof);
					}
				}
			);
	}

	
	
	
}