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"Go Wild Wirelessly with Bluetooth and Java"
Vol. 9, Issue 2, p. 26


Listing 1: Creating a server connection

     // BlueChat specific service UUID
      private final static UUID uuid = new UUID(0x6600BC);


      StreamConnectionNotifier server = null;

      // Create a server connection object, using a
      // Serial Port Profile URL syntax and our specific UUID (0x6600BC)
      // and set the service name to BlueChatApp
      server =  (StreamConnectionNotifier)Connector.open(
          "btspp://localhost:" + uuid.toString() +";name=BlueChatApp");

      // Retrieve the service record template
      ServiceRecord rec = localDevice.getRecord( server );

      // set ServiceAvailability (0x0008) attribute to indicate our service is
      // 0xFF indicate fully available status
      // This operation is optional
      rec.setAttributeValue( 0x0008, new DataElement( DataElement.U_INT_1, 0xFF )
	// Print the service record, which already contains
      // some default values
      Util.printServiceRecord( rec );
	// Set the Major Service Classes flag in Bluetooth stack.
      // We choose Object Transfer Service
          BluetoothConstants.SERVICE_OBJECT_TRANSFER  );
Listing 2: Start discovering near-by devices

 // initialize the JABWT stack
      LocalDevice device = LocalDevice.getLocalDevice(); 
	  // obtain reference to singleton
      device.setDiscoverable( DiscoveryAgent.LIAC ); 
	  // set Discover mode to LIAC
      DiscoveryAgent agent = device.getDiscoveryAgent(); 
	  // obtain reference to singleton

      // although JSR-82 provides the ability to lookup
      // cached and preknown devices, we intentionally by-pass
      // them and go to discovery mode directly.
      // this allow us to retrieve the latest active BlueChat parties
// Listener object implements DiscoveryListener
      agent.startInquiry(DiscoveryAgent.LIAC, new Listener() );

Listing 3: Filtering relevant devices into pending EndPoint list

     * A device is discovered.
     * Create a EndPoint for the device discovered and put it on the pending list.
     * A service search will happen when all the qualifying devices are discovered.
    public void deviceDiscovered(RemoteDevice remoteDevice,
                                 DeviceClass deviceClass)

// only device of SERVICE_OBJECT_TRANSFER service 
// will be considered as candidate device
      // because in our BlueChat service, we explicitly set the service class to
      // SERVICE_OBJECT_TRANSFER. see the run() method
      if ( (deviceClass.getServiceClasses() & 
 BluetoothConstants.SERVICE_OBJECT_TRANSFER) != 0 )
          // create a inactive EndPoint and put it on the pending list
          EndPoint endpt = new EndPoint(NetLayer.this, remoteDevice, null);

          pendingEndPoints.addElement( endpt );

        } catch (Exception e)

Listing 4: Start discovering BlueChat services

     * device discovery completed.
     * After device inquery completed, we start to search for BlueChat services.
     * We loop through all the pending EndPoints and request agent.searchServices
     * on each of the remote device.
    public void inquiryCompleted(int transId)
      // for each EndPoint, we search for BlueChat
      // services, i.e. ServiceClassIDList (0x0001) = uuid (0x6600BC)
      for (int i = 0; i < pendingEndPoints.size(); i++)
        EndPoint endpt = (EndPoint) endPoints.elementAt(i);

          // searchServices return a transaction id, which we will used to
          // identify which remote device the service is found in our callback
          // listener (class Listener)
          endpt.transId = agent.searchServices(new int[] {0x0001}, 
// attribute ID for ServiceClassIDList new UUID[] {uuid}  
// BlueChat service UUID endpt.remoteDev, new Listener());

Listing 5: Establishing connection to discovered BlueChat services

     * a service is discovered from a remote device.
     * when a BlueChat service is discovered, we establish a connection to
     * this service. This signal joining the existing virtual chat room.
    public void servicesDiscovered(int transId, ServiceRecord[] svcRec)

        if ( svcRec.length > 0 )
// We make an assumption that the first service is BlueChat. In fact, only one
// service record will be found on each device.
// Note: we know the found service is BlueChat service because we search on 
// specific UUID, and this UUID is unique to us
          String url  = svcRec[0].getConnectionURL(
          StreamConnection con = (StreamConnection)Connector.open( url );

	// Establish active EndPoint
	// and start sending SIGNAL_HANDSHAKE


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