hi guys ...
this is asimple code for multicast chatting.....
import java.net.*;
import java.io.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.Calendar;
/*
* Multicast based chat system with a very simple GUI using SWING
* The main thread does the sending, while a secondary thread (the reader)
* does the receiving of messages
*/
public class MultiChat extends JPanel implements ActionListener
{
JTextArea textarea = null;
JTextField textfield = null;
JScrollPane scrollpane = null;
private String id;
private MulticastSocket socket = null;
private SocketAddress dest = null;
/**
* Send the text to the multicast group.
* Add the name of the user in front of the message.
*/
private void send(String msg) throws IOException
{
String buf = id + ">> " + msg;
byte[] b = buf.getBytes();
DatagramPacket packet = new DatagramPacket(b, 0, b.length, dest);
socket.send(packet);
}
/**
* Reader thread.
*/
class Reader extends Thread {
public void run() {
byte[] buf = new byte[512];
DatagramPacket p = null;
// Just loop forever, as the main thread will take care of the
// exit conditions
while (true) {
try {
p = new DatagramPacket(buf, buf.length);
socket.receive(p);
} catch (IOException e) {
e.printStackTrace();
}
// We got a packet, let's extract the message and display it
String line = new String(p.getData(), 0, p.getLength());
textarea.append(line);
textarea.append("\n");
}
}
}
/**
* Main constructor.
* Takes a String containing the name (or id) of the user.
*/
MultiChat(String name) {
super(true);
id = name;
// This is the multicast group we'll be using.
dest = new InetSocketAddress("228.5.6.7", 4321);
try {
// The socket is created and bound to the proper port.
socket = new MulticastSocket(4321);
// Set the loopback mode to false if you don't want to see your
// own messages
//socket.setLoopbackMode(false);
// get the default Network Interface
NetworkInterface netif = NetworkInterface.getByInetAddress(InetAddress.getLocalHost());
// Join the multicast group
socket.joinGroup(dest, netif);
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
}
// From here onwards, the GUI is created
// Force SwingSet to come up in the Cross Platform L&F
try
{
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
// If you want the System L&F instead, comment out the above line and
// uncomment the following:
// UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception exc) {
System.err.println("Error loading L&F: " + exc);
}
setBorder(BorderFactory.createEtchedBorder());
setLayout(new BorderLayout());
setFocusCycleRoot(true);
setRequestFocusEnabled(true);
// Create the area in which the messages will be seen after a RETURN is hit.
// Using the JTextArea class to construct the GUI for this purpose.
textarea = new JTextArea();
//textarea.setBackground(Color.cyan);
textarea.setLineWrap(true);
textarea.setWrapStyleWord(true);
textarea.setEditable(false);
scrollpane = new JScrollPane(textarea);
scrollpane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
// Create the area in which the user can key in the text message to be displayed.
// Using the JTextField class to construct the GUI for this purpose.
textfield = new JTextField();
//textfield.setBackground(Color.yellow);
textfield.setDragEnabled(true);
textfield.requestFocus(true);
add("Center", scrollpane);
add("South", textfield);
textfield.addActionListener(this);
Reader r = new Reader();
r.start();
}
// When the user hits <RETURN> this method is called
public void actionPerformed(ActionEvent evt) {
String text = textfield.getText();
try {
// So you want to quit?
if ("quit".equalsIgnoreCase(text)) {
// Let's be nice
send("Goodbye!");
System.exit(1);
}
// OK, let's just send the message then
send(text);
// And clear the TextField
textfield.setText("");
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* To shutdown when run as an application. This is a
* fairly lame implementation. A more self-respecting
* implementation would at least check to see if a save
* was needed.
*/
protected static final class AppCloser extends WindowAdapter {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}
/**
* main() method of this program. The method creates a frame with Border Layout
* and adds the MultiChat GUI onto the center of the frame with text string as
* a label on the bottom of the frame to inform the user how to quit the application.
*/
public static void main(String[] args) throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
String name;
System.out.println("Enter your name :");
name=br.readLine();
if (args.length > 0)
name = args[0];
JFrame frame = new JFrame();
frame.setTitle(name + "@ChatRoom");
// Add the comps...
frame.getContentPane().setLayout(new BorderLayout());
frame.getContentPane().add("Center", new MultiChat(name));
frame.getContentPane().add("South", new JLabel("Type \'quit\' to exit or just close the window"));
frame.addWindowListener(new AppCloser());
frame.pack();
frame.setSize(400, 200);
frame.show();
}
}
