This article provides Java sample codes to search for Bluetooth devices using a JSR-82 API. If you are new to JSR-82, we recommend you to read the JSR-82 Basics tutorial to get a basic idea Java and Bluetooth.

JSR-82 provides the class DiscoveryAgent for performing Device Discovery and Service Discovery. The LocalDevice class provides a factory method 'getDiscoveryAgent' that returns a singleton instance of the DiscoveryAgent. This instance can then be used to discover other bluetooth devices and services.

The following code sample shows you how to use the DiscoveryAgent to discover other bluetooth devices. For this sample to work, you need a JSR-82 Implmentation (Java Bluetooth Stack) like ElectricBlue or aveLink in the classpath.

BluetoothDeviceDiscovery.java

import java.io.IOException;

import java.util.Vector;



import javax.bluetooth.DeviceClass;

import javax.bluetooth.DiscoveryAgent;

import javax.bluetooth.DiscoveryListener;

import javax.bluetooth.LocalDevice;

import javax.bluetooth.RemoteDevice;

import javax.bluetooth.ServiceRecord;





/**

* Class that discovers all bluetooth devices in the neighbourhood

* and displays their name and bluetooth address.

*/

public class BluetoothDeviceDiscovery implements DiscoveryListener{





//object used for waiting

private static Object lock=new Object();



//vector containing the devices discovered

private static Vector vecDevices=new Vector();





//main method of the application

public static void main(String[] args) throws IOException {



//create an instance of this class

BluetoothDeviceDiscovery bluetoothDeviceDiscovery=new BluetoothDeviceDiscovery();



//display local device address and name

LocalDevice localDevice = LocalDevice.getLocalDevice();

System.out.println("Address: "+localDevice.getBluetoothAddress());

System.out.println("Name: "+localDevice.getFriendlyName());



//find devices

DiscoveryAgent agent = localDevice.getDiscoveryAgent();



System.out.println("Starting device inquiry...");

agent.startInquiry(DiscoveryAgent.GIAC, bluetoothDeviceDiscovery);



try {

synchronized(lock){

lock.wait();

}

}

catch (InterruptedException e) {

e.printStackTrace();

}





System.out.println("Device Inquiry Completed. ");



//print all devices in vecDevices

int deviceCount=vecDevices.size();



if(deviceCount <= 0){

System.out.println("No Devices Found .");

}

else{

//print bluetooth device addresses and names in the format [ No. address (name)
]

System.out.println("Bluetooth Devices: ");

for (int i = 0; i <deviceCount; i++) {

RemoteDevice remoteDevice=(RemoteDevice)vecDevices.elementAt(i);

System.out.println((i+1)+". "+remoteDevice.getBluetoothAddress()+"
("+remoteDevice.getFriendlyName(true)+")");

}

}





}//end main



//methods of DiscoveryListener



/**

* This call back method will be called for each discovered bluetooth devices.

*/

public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) {

System.out.println("Device discovered: "+btDevice.getBluetoothAddress());

//add the device to the vector

if(!vecDevices.contains(btDevice)){

vecDevices.addElement(btDevice);

}

}



//no need to implement this method since services are not being discovered

public void servicesDiscovered(int transID, ServiceRecord[] servRecord) {

}



//no need to implement this method since services are not being discovered

public void serviceSearchCompleted(int transID, int respCode) {

}





/**

* This callback method will be called when the device discovery is

* completed.

*/

public void inquiryCompleted(int discType) {

synchronized(lock){

lock.notify();

}



switch (discType) {

case DiscoveryListener.INQUIRY_COMPLETED :

System.out.println("INQUIRY_COMPLETED");

break;



case DiscoveryListener.INQUIRY_TERMINATED :

System.out.println("INQUIRY_TERMINATED");

break;



case DiscoveryListener.INQUIRY_ERROR :

System.out.println("INQUIRY_ERROR");

break;



default :

System.out.println("Unknown Response Code");

break;

}

}//end method

}//end class