Clients/Java/SimpleChat.java

   1 /* -*- Mode: Java; tab-width: 4 -*-
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  39
  40         SimpleChat is a simple peer-to-peer chat program that demonstrates
  41         DNS-SD registration, browsing, resolving and record-querying.
  42
  43         To do:
  44         - implement better coloring algorithm
  45  */
  46
  47
  48 import java.awt.*;
  49 import java.awt.event.*;
  50 import java.text.*;
  51 import java.net.*;
  52 import javax.swing.*;
  53 import javax.swing.event.*;
  54 import javax.swing.text.*;
  55
  56 import com.apple.dnssd.*;
  57
  58
  59 class   SimpleChat implements   ResolveListener, RegisterListener, QueryListener,
  60                                                                 ActionListener, ItemListener, Runnable
  61 {
  62         Document                        textDoc;                        // Holds all the chat text
  63         JTextField                      inputField;                     // Holds a pending chat response
  64         String                          ourName;                        // name used to identify this user in chat
  65         DNSSDService            browser;                        // object that actively browses for other chat clients
  66         DNSSDService            resolver;                       // object that resolves other chat clients
  67         DNSSDRegistration       registration;           // object that maintains our connection advertisement
  68         JComboBox                       targetPicker;           // Indicates who we're talking to
  69         TargetListModel         targetList;                     // and its list model
  70         JButton                         sendButton;                     // Will send text in inputField to target
  71         InetAddress                     buddyAddr;                      // and address
  72         int                                     buddyPort;                      // and port
  73         DatagramPacket          dataPacket;                     // Inbound data packet
  74         DatagramSocket          outSocket;                      // Outbound data socket
  75         SimpleAttributeSet      textAttribs;
  76
  77         static final String     kChatExampleRegType = "_p2pchat._udp";
  78         static final String     kWireCharSet = "ISO-8859-1";
  79
  80         public          SimpleChat() throws Exception
  81         {
  82                 JFrame frame = new JFrame("SimpleChat");
  83                 frame.addWindowListener(new WindowAdapter() {
  84                         public void windowClosing(WindowEvent e) {System.exit(0);}
  85                 });
  86
  87         ourName = System.getProperty( "user.name");
  88                 targetList = new TargetListModel();
  89                 textAttribs = new SimpleAttributeSet();
  90                 DatagramSocket inSocket = new DatagramSocket();
  91                 dataPacket = new DatagramPacket( new byte[ 4096], 4096);
  92                 outSocket = new DatagramSocket();
  93
  94                 this.setupSubPanes( frame.getContentPane(), frame.getRootPane());
  95                 frame.pack();
  96                 frame.setVisible(true);
  97                 inputField.requestFocusInWindow();
  98
  99                 browser = DNSSD.browse( 0, 0, kChatExampleRegType, "", new SwingBrowseListener( targetList));
 100
 101                 registration = DNSSD.register( 0, 0, ourName, kChatExampleRegType, "", "", inSocket.getLocalPort(), null, this);
 102
 103                 new ListenerThread( this, inSocket, dataPacket).start();
 104         }
 105
 106         protected void  setupSubPanes( Container parent, JRootPane rootPane)
 107         {
 108                 parent.setLayout( new BoxLayout( parent, BoxLayout.Y_AXIS));
 109
 110                 JPanel textRow = new JPanel();
 111                 textRow.setLayout( new BoxLayout( textRow, BoxLayout.X_AXIS));
 112                 textRow.add( Box.createRigidArea( new Dimension( 16, 0)));
 113                 JEditorPane textPane = new JEditorPane( "text/html", "<BR>");
 114                 textPane.setPreferredSize( new Dimension( 400, 300));
 115                 textPane.setEditable( false);
 116                 JScrollPane textScroller = new JScrollPane( textPane);
 117                 textRow.add( textScroller);
 118                 textRow.add( Box.createRigidArea( new Dimension( 16, 0)));
 119                 textDoc = textPane.getDocument();
 120
 121                 JPanel addressRow = new JPanel();
 122                 addressRow.setLayout( new BoxLayout( addressRow, BoxLayout.X_AXIS));
 123                 targetPicker = new JComboBox( targetList);
 124                 targetPicker.addItemListener( this);
 125                 addressRow.add( Box.createRigidArea( new Dimension( 16, 0)));
 126                 addressRow.add( new JLabel( "Talk to: "));
 127                 addressRow.add( targetPicker);
 128                 addressRow.add( Box.createHorizontalGlue());
 129
 130                 JPanel buttonRow = new JPanel();
 131                 buttonRow.setLayout( new BoxLayout( buttonRow, BoxLayout.X_AXIS));
 132                 buttonRow.add( Box.createRigidArea( new Dimension( 16, 0)));
 133                 inputField = new JTextField();
 134                 // prevent inputField from hijacking <Enter> key
 135                 inputField.getKeymap().removeKeyStrokeBinding( KeyStroke.getKeyStroke( KeyEvent.VK_ENTER, 0));
 136                 buttonRow.add( inputField);
 137                 sendButton = new JButton( "Send");
 138                 buttonRow.add( Box.createRigidArea( new Dimension( 8, 0)));
 139                 buttonRow.add( sendButton);
 140                 buttonRow.add( Box.createRigidArea( new Dimension( 16, 0)));
 141                 rootPane.setDefaultButton( sendButton);
 142                 sendButton.addActionListener( this);
 143                 sendButton.setEnabled( false);
 144
 145                 parent.add( Box.createRigidArea( new Dimension( 0, 16)));
 146                 parent.add( textRow);
 147                 parent.add( Box.createRigidArea( new Dimension( 0, 8)));
 148                 parent.add( addressRow);
 149                 parent.add( Box.createRigidArea( new Dimension( 0, 8)));
 150                 parent.add( buttonRow);
 151                 parent.add( Box.createRigidArea( new Dimension( 0, 16)));
 152         }
 153
 154         public void     serviceRegistered( DNSSDRegistration registration, int flags,
 155                                                                         String serviceName, String regType, String domain)
 156         {
 157                 ourName = serviceName;          // might have been renamed on collision
 158         }
 159
 160         public void     operationFailed( DNSSDService service, int errorCode)
 161         {
 162                 System.out.println( "Service reported error " + String.valueOf( errorCode));
 163         }
 164
 165         public void     serviceResolved( DNSSDService resolver, int flags, int ifIndex, String fullName,
 166                                                                                 String hostName, int port, TXTRecord txtRecord)
 167         {
 168                 buddyPort = port;
 169                 try {
 170                         // Start a record query to obtain IP address from hostname
 171                         DNSSD.queryRecord( 0, ifIndex, hostName, 1 /* ns_t_a */, 1 /* ns_c_in */,
 172                                                                 new SwingQueryListener( this));
 173                 }
 174                 catch ( Exception e) { terminateWithException( e); }
 175                 resolver.stop();
 176         }
 177
 178         public void     queryAnswered( DNSSDService query, int flags, int ifIndex, String fullName,
 179                                                                         int rrtype, int rrclass, byte[] rdata, int ttl)
 180         {
 181                 try {
 182                         buddyAddr = InetAddress.getByAddress( rdata);
 183                 }
 184                 catch ( Exception e) { terminateWithException( e); }
 185                 sendButton.setEnabled( true);
 186         }
 187
 188         public void             actionPerformed( ActionEvent e)         // invoked when Send button is hit
 189         {
 190                 try
 191                 {
 192                         String  sendString = ourName + ": " + inputField.getText();
 193                         byte[] sendData = sendString.getBytes( kWireCharSet);
 194                         outSocket.send( new DatagramPacket( sendData, sendData.length, buddyAddr, buddyPort));
 195                         StyleConstants.setForeground( textAttribs, Color.black);
 196                         textDoc.insertString( textDoc.getLength(), inputField.getText() + "\n", textAttribs);
 197                         inputField.setText( "");
 198                 }
 199                 catch ( Exception exception) { terminateWithException( exception); }
 200         }
 201
 202         public void             itemStateChanged( ItemEvent e)  // invoked when Target selection changes
 203         {
 204                 sendButton.setEnabled( false);
 205                 if ( e.getStateChange() == ItemEvent.SELECTED)
 206                 {
 207                         try {
 208                                 TargetListElem  sel = (TargetListElem) targetList.getSelectedItem();
 209                                 resolver = DNSSD.resolve( 0, sel.fInt, sel.fServiceName, sel.fType, sel.fDomain, this);
 210                         }
 211                         catch ( Exception exception) { terminateWithException( exception); }
 212                 }
 213         }
 214
 215         public void             run()           // invoked on event thread when inbound packet arrives
 216         {
 217                 try
 218                 {
 219                         String  inMessage = new String( dataPacket.getData(), 0, dataPacket.getLength(), kWireCharSet);
 220                         StyleConstants.setForeground( textAttribs, this.getColorFor( dataPacket.getData(), dataPacket.getLength()));
 221                         textDoc.insertString( textDoc.getLength(), inMessage + "\n", textAttribs);
 222                 }
 223                 catch ( Exception e) { terminateWithException( e); }
 224         }
 225
 226         protected Color         getColorFor( byte[] chars, int length)
 227         // Produce a mapping from a string to a color, suitable for text display
 228         {
 229                 int             rgb = 0;
 230                 for ( int i=0; i < length && chars[i] != ':'; i++)
 231                         rgb = rgb ^ ( (int) chars[i] << (i%3+2) * 8);
 232                 return new Color( rgb & 0x007F7FFF);    // mask off high bits so it is a dark color
 233
 234 //              for ( int i=0; i < length && chars[i] != ':'; i++)
 235
 236         }
 237
 238         protected static void   terminateWithException( Exception e)
 239         {
 240                 e.printStackTrace();
 241                 System.exit( -1);
 242         }
 243
 244     public static void main(String s[])
 245     {
 246         try {
 247                         new SimpleChat();
 248                 }
 249                 catch ( Exception e) { terminateWithException( e); }
 250     }
 251 }
 252
 253
 254
 255 class   TargetListElem
 256 {
 257         public  TargetListElem( String serviceName, String domain, String type, int ifIndex)
 258         { fServiceName = serviceName; fDomain = domain; fType = type; fInt = ifIndex; }
 259
 260         public String   toString() { return fServiceName; }
 261
 262         public String   fServiceName, fDomain, fType;
 263         public int              fInt;
 264 }
 265
 266 class           TargetListModel extends DefaultComboBoxModel implements BrowseListener
 267 {
 268         /* The Browser invokes this callback when a service is discovered. */
 269         public void     serviceFound( DNSSDService browser, int flags, int ifIndex,
 270                                                         String serviceName, String regType, String domain)
 271         {
 272                 TargetListElem          match = this.findMatching( serviceName);        // probably doesn't handle near-duplicates well.
 273
 274                 if ( match == null)
 275                         this.addElement( new TargetListElem( serviceName, domain, regType, ifIndex));
 276         }
 277
 278         /* The Browser invokes this callback when a service disappears. */
 279         public void     serviceLost( DNSSDService browser, int flags, int ifIndex,
 280                                                         String serviceName, String regType, String domain)
 281         {
 282                 TargetListElem          match = this.findMatching( serviceName);        // probably doesn't handle near-duplicates well.
 283
 284                 if ( match != null)
 285                         this.removeElement( match);
 286         }
 287
 288         /* The Browser invokes this callback when a service disappears. */
 289         public void     operationFailed( DNSSDService service, int errorCode)
 290         {
 291                 System.out.println( "Service reported error " + String.valueOf( errorCode));
 292         }
 293
 294         protected TargetListElem        findMatching( String match)
 295         {
 296                 for ( int i = 0; i < this.getSize(); i++)
 297                         if ( match.equals( this.getElementAt( i).toString()))
 298                                 return (TargetListElem) this.getElementAt( i);
 299                 return null;
 300         }
 301
 302 }
 303
 304
 305 // A ListenerThread runs its owner when datagram packet p appears on socket s.
 306 class   ListenerThread extends Thread
 307 {
 308         public                  ListenerThread( Runnable owner, DatagramSocket s, DatagramPacket p)
 309         { fOwner = owner; fSocket = s; fPacket = p; }
 310
 311         public void             run()
 312         {
 313                 while ( true )
 314                 {
 315                         try
 316                         {
 317                                 fSocket.receive( fPacket);
 318                                 SwingUtilities.invokeAndWait( fOwner);  // process data on main thread
 319                         }
 320                         catch( Exception e)
 321                         {
 322                                 break;  // terminate thread
 323                         }
 324                 }
 325         }
 326
 327         protected Runnable                      fOwner;
 328         protected DatagramSocket        fSocket;
 329         protected DatagramPacket        fPacket;
 330 }
 331
 332
 333