蓝牙，BlueCove和Raspberry PI

Question

I setup using Java using BlueJ and Bluetooth using Blueman on my RaspberryPI and am using the BlueCove API.

I took the example RemoteDeviceDiscovery from:

http://bluecove.org/bluecove/apidocs/overview-summary.html#DeviceDiscovery

When I run the example from within BlueJ I get:

" wait for device inquiry to complete... Device Inquiry completed! 0 device(s) found " and when I run from the terminal window using:

pi@raspberrypi ~/java/bluetooth_jar $ /usr/lib/jvm/jdk-8-oracle-arm-vfp-hflt/jre/bin/java -jar bluetooth_jar.jar

I get:

" BlueCove version 2.1.1-SNAPSHOT on bluez BluetoothStateException exception: javax.bluetooth.BluetoothStateException: Bluetooth Device is not ready. [1] Operation not permitted BlueCove stack shutdown completed "

Why the exception is not thrown when using BlueJ I don't understand but from the commandline it appears unable to detect nearby devices because the device is not ready. However, I don't understand this error message since I can send files using Blueman Manager to nearby a Android tablet and Win7 laptop.

import java.io.IOException;

import java.util.ArrayList; import javax.bluetooth.*;

/** * Minimal Device Discovery example. */ public class RemoteDeviceDiscovery {

protected ArrayList<RemoteDevice> devicesDiscovered = new ArrayList();
protected final Object inquiryCompletedEvent = new Object();

public RemoteDeviceDiscovery()
{
    DiscoveryListener listener = new MyDiscoveryListener();

    synchronized(inquiryCompletedEvent) {
        try
        {
            LocalDevice local = LocalDevice.getLocalDevice();
            local.setDiscoverable(DiscoveryAgent.GIAC);
            DiscoveryAgent discoveryAgent = local.getDiscoveryAgent();
            // note: GIAC: The inquiry access code for General/Unlimited Inquiry Access Code (GIAC).
            boolean startedInquiry = discoveryAgent.startInquiry(DiscoveryAgent.GIAC, listener);
            if (startedInquiry)
            {
                System.out.println("wait for device inquiry to complete...");
                inquiryCompletedEvent.wait();
                System.out.println(devicesDiscovered.size() +  " device(s) found");
            }
        }
        catch ( BluetoothStateException e)
        {
            System.out.println("BluetoothStateException exception: " + e);
        }
        catch (InterruptedException e)
        {
            System.out.println("InterruptedException exception: " + e);
        }
    }        
}

public static void main(String[] args)
{

    RemoteDeviceDiscovery rmd = new RemoteDeviceDiscovery();
}

class MyDiscoveryListener implements DiscoveryListener
{
    public MyDiscoveryListener()
    {
    }

    public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) {
        System.out.println("Device " + btDevice.getBluetoothAddress() + " found");
        devicesDiscovered.add(btDevice);
        try {
            System.out.println("     name " + btDevice.getFriendlyName(false));
        } catch (IOException cantGetDeviceName) {
        }
    }

    public void inquiryCompleted(int discType) {
        System.out.println("Device Inquiry completed!");
        synchronized(inquiryCompletedEvent){
            inquiryCompletedEvent.notifyAll();
        }
    }

    public void serviceSearchCompleted(int transID, int respCode) {
    }

    public void servicesDiscovered(int transID, ServiceRecord[] servRecord) {
    }    
} // class MyDiscoveryListener

} // class RemoteDeviceDiscovery

Answer 1

Discovered that if I run the jar with superuser rights then it works as expected:

pi@raspberrypi ~ sudo /java/bluetooth_jar $ /usr/lib/jvm/jdk-8-oracle-arm-vfp-hflt/jre/bin/java -jar bluetooth_jar.jar

with output:

BlueCove version 2.1.1-SNAPSHOT on bluez wait for device inquiry to complete... Device C4850852975B found name GMSEED-PC Device Inquiry completed! 1 device(s) found BlueCove stack shutdown completed

and if I start BlueJ as superuser from the commandline rather than through the desktop menu item Menu|Programming|BlueJ; ie:

pi@raspberrypi ~ $ sudo bluej

and then the example app gives the same output.