import java.awt.*;

import java.awt.event.*;

import java.text.*;

import java.net.*;

import javax.swing.*;

import javax.swing.event.*;

import javax.swing.text.*;

import com.apple.dnssd.*;

class SimpleChat implements ResolveListener, RegisterListener, QueryListener,

ActionListener, ItemListener, Runnable

{

Document textDoc; // Holds all the chat text

JTextField inputField; // Holds a pending chat response

String ourName; // name used to identify this user in chat

DNSSDService browser; // object that actively browses for other chat clients

DNSSDService resolver; // object that resolves other chat clients

DNSSDRegistration registration; // object that maintains our connection advertisement

JComboBox targetPicker; // Indicates who we're talking to

TargetListModel targetList; // and its list model

JButton sendButton; // Will send text in inputField to target

InetAddress buddyAddr; // and address

int buddyPort; // and port

DatagramPacket dataPacket; // Inbound data packet

DatagramSocket outSocket; // Outbound data socket

SimpleAttributeSet textAttribs;

static final String kChatExampleRegType = "_p2pchat._udp";

static final String kWireCharSet = "ISO-8859-1";

public SimpleChat() throws Exception

{

JFrame frame = new JFrame("SimpleChat");

frame.addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {System.exit(0);}

});

ourName = System.getProperty( "user.name");

targetList = new TargetListModel();

textAttribs = new SimpleAttributeSet();

DatagramSocket inSocket = new DatagramSocket();

dataPacket = new DatagramPacket( new byte[ 4096], 4096);

outSocket = new DatagramSocket();

this.setupSubPanes( frame.getContentPane(), frame.getRootPane());

frame.pack();

frame.setVisible(true);

inputField.requestFocusInWindow();

browser = DNSSD.browse( 0, 0, kChatExampleRegType, "", new SwingBrowseListener( targetList));

registration = DNSSD.register( 0, 0, ourName, kChatExampleRegType, "", "", inSocket.getLocalPort(), null, this);

new ListenerThread( this, inSocket, dataPacket).start();

}

protected void setupSubPanes( Container parent, JRootPane rootPane)

{

parent.setLayout( new BoxLayout( parent, BoxLayout.Y_AXIS));

JPanel textRow = new JPanel();

textRow.setLayout( new BoxLayout( textRow, BoxLayout.X_AXIS));

textRow.add( Box.createRigidArea( new Dimension( 16, 0)));

JEditorPane textPane = new JEditorPane( "text/html", "<BR>");

textPane.setPreferredSize( new Dimension( 400, 300));

textPane.setEditable( false);

JScrollPane textScroller = new JScrollPane( textPane);

textRow.add( textScroller);

textRow.add( Box.createRigidArea( new Dimension( 16, 0)));

textDoc = textPane.getDocument();

JPanel addressRow = new JPanel();

addressRow.setLayout( new BoxLayout( addressRow, BoxLayout.X_AXIS));

targetPicker = new JComboBox( targetList);

targetPicker.addItemListener( this);

addressRow.add( Box.createRigidArea( new Dimension( 16, 0)));

addressRow.add( new JLabel( "Talk to: "));

addressRow.add( targetPicker);

addressRow.add( Box.createHorizontalGlue());

JPanel buttonRow = new JPanel();

buttonRow.setLayout( new BoxLayout( buttonRow, BoxLayout.X_AXIS));

buttonRow.add( Box.createRigidArea( new Dimension( 16, 0)));

inputField = new JTextField();

// prevent inputField from hijacking <Enter> key

inputField.getKeymap().removeKeyStrokeBinding( KeyStroke.getKeyStroke( KeyEvent.VK_ENTER, 0));

buttonRow.add( inputField);

sendButton = new JButton( "Send");

buttonRow.add( Box.createRigidArea( new Dimension( 8, 0)));

buttonRow.add( sendButton);

buttonRow.add( Box.createRigidArea( new Dimension( 16, 0)));

rootPane.setDefaultButton( sendButton);

sendButton.addActionListener( this);

sendButton.setEnabled( false);

parent.add( Box.createRigidArea( new Dimension( 0, 16)));

parent.add( textRow);

parent.add( Box.createRigidArea( new Dimension( 0, 8)));

parent.add( addressRow);

parent.add( Box.createRigidArea( new Dimension( 0, 8)));

parent.add( buttonRow);

parent.add( Box.createRigidArea( new Dimension( 0, 16)));

}

public void serviceRegistered( DNSSDRegistration registration, int flags,

String serviceName, String regType, String domain)

{

ourName = serviceName; // might have been renamed on collision

}

public void operationFailed( DNSSDService service, int errorCode)

{

System.out.println( "Service reported error " + String.valueOf( errorCode));

}

public void serviceResolved( DNSSDService resolver, int flags, int ifIndex, String fullName,

String hostName, int port, TXTRecord txtRecord)

{

buddyPort = port;

try {

// Start a record query to obtain IP address from hostname

DNSSD.queryRecord( 0, ifIndex, hostName, 1 /* ns_t_a */, 1 /* ns_c_in */,

new SwingQueryListener( this));

}

catch ( Exception e) { terminateWithException( e); }

resolver.stop();

}

public void queryAnswered( DNSSDService query, int flags, int ifIndex, String fullName,

int rrtype, int rrclass, byte[] rdata, int ttl)

{

try {

buddyAddr = InetAddress.getByAddress( rdata);

}

catch ( Exception e) { terminateWithException( e); }

sendButton.setEnabled( true);

}

public void actionPerformed( ActionEvent e) // invoked when Send button is hit

{

try

{

String sendString = ourName + ": " + inputField.getText();

byte[] sendData = sendString.getBytes( kWireCharSet);

outSocket.send( new DatagramPacket( sendData, sendData.length, buddyAddr, buddyPort));

StyleConstants.setForeground( textAttribs, Color.black);

textDoc.insertString( textDoc.getLength(), inputField.getText() + "\n", textAttribs);

inputField.setText( "");

}

catch ( Exception exception) { terminateWithException( exception); }

}

public void itemStateChanged( ItemEvent e) // invoked when Target selection changes

{

sendButton.setEnabled( false);

if ( e.getStateChange() == ItemEvent.SELECTED)

{

try {

TargetListElem sel = (TargetListElem) targetList.getSelectedItem();

resolver = DNSSD.resolve( 0, sel.fInt, sel.fServiceName, sel.fType, sel.fDomain, this);

}

catch ( Exception exception) { terminateWithException( exception); }

}

}

public void run() // invoked on event thread when inbound packet arrives

{

try

{

String inMessage = new String( dataPacket.getData(), 0, dataPacket.getLength(), kWireCharSet);

StyleConstants.setForeground( textAttribs, this.getColorFor( dataPacket.getData(), dataPacket.getLength()));

textDoc.insertString( textDoc.getLength(), inMessage + "\n", textAttribs);

}

catch ( Exception e) { terminateWithException( e); }

}

protected Color getColorFor( byte[] chars, int length)

// Produce a mapping from a string to a color, suitable for text display

{

int rgb = 0;

for ( int i=0; i < length && chars[i] != ':'; i++)

rgb = rgb ^ ( (int) chars[i] << (i%3+2) * 8);

return new Color( rgb & 0x007F7FFF); // mask off high bits so it is a dark color

}

protected static void terminateWithException( Exception e)

{

e.printStackTrace();

System.exit( -1);

}

public static void main(String s[])

{

try {

new SimpleChat();

}

catch ( Exception e) { terminateWithException( e); }

}

}

class TargetListElem

{

public TargetListElem( String serviceName, String domain, String type, int ifIndex)

{ fServiceName = serviceName; fDomain = domain; fType = type; fInt = ifIndex; }

public String toString() { return fServiceName; }

public String fServiceName, fDomain, fType;

public int fInt;

}

class TargetListModel extends DefaultComboBoxModel implements BrowseListener

{

/* The Browser invokes this callback when a service is discovered. */

public void serviceFound( DNSSDService browser, int flags, int ifIndex,

String serviceName, String regType, String domain)

{

TargetListElem match = this.findMatching( serviceName); // probably doesn't handle near-duplicates well.

if ( match == null)

this.addElement( new TargetListElem( serviceName, domain, regType, ifIndex));

}

/* The Browser invokes this callback when a service disappears. */

public void serviceLost( DNSSDService browser, int flags, int ifIndex,

String serviceName, String regType, String domain)

{

TargetListElem match = this.findMatching( serviceName); // probably doesn't handle near-duplicates well.

if ( match != null)

this.removeElement( match);

}

/* The Browser invokes this callback when a service disappears. */

public void operationFailed( DNSSDService service, int errorCode)

{

System.out.println( "Service reported error " + String.valueOf( errorCode));

}

protected TargetListElem findMatching( String match)

{

for ( int i = 0; i < this.getSize(); i++)

if ( match.equals( this.getElementAt( i).toString()))

return (TargetListElem) this.getElementAt( i);

return null;

}

}

class ListenerThread extends Thread

{

public ListenerThread( Runnable owner, DatagramSocket s, DatagramPacket p)

{ fOwner = owner; fSocket = s; fPacket = p; }

public void run()

{

while ( true )

{

try

{

fSocket.receive( fPacket);

SwingUtilities.invokeAndWait( fOwner); // process data on main thread

}

catch( Exception e)

{

break; // terminate thread

}

}

}

protected Runnable fOwner;

protected DatagramSocket fSocket;

protected DatagramPacket fPacket;

}