Rx Wrapper around Bluetooth Low Energy scan process

RxScanner

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.text.TextUtils;

import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.functions.Action0;
import rx.schedulers.Schedulers;

/**
Rx Wrapper around Bluetooth Low Energy scan process
*/
public class RxScanner {


    final BluetoothAdapter adapter;
    private LeCallback callback;

    public RxScanner(BluetoothAdapter adapter) {
        this.adapter = adapter;
    }

    /**
      Scan observable, subscribe to start scan, unsubscribe to finish
    */
    public Observable<DeviceEntry> observe() {
        return Observable.create(new Observable.OnSubscribe<DeviceEntry>() {
            @Override
            public void call(final Subscriber<? super DeviceEntry> subscriber) {
                callback = new LeCallback(subscriber);
                adapter.startLeScan(callback);
            }
        })
                .doOnUnsubscribe(new Action0() {
                    @Override
                    public void call() {
                        adapter.stopLeScan(callback);
                        callback.onComplete();
                    }
                })
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread());
    }

    private static class LeCallback implements BluetoothAdapter.LeScanCallback {
        
        final Subscriber<? super DeviceEntry> subscriber;

        private LeCallback(Subscriber<? super DeviceEntry> subscriber) {
            this.subscriber = subscriber;
        }

        @Override
        public void onLeScan(final BluetoothDevice device, int rssi, final byte[] scanRecord) {
            if (isCompleted) {
                return;
            }
            subscriber.onNext(new DeviceEntry(device, scanRecord));
        }

        private volatile boolean isCompleted = false;

        public void onComplete() {
            isCompleted = true;
            subscriber.onCompleted();
        }
    }
}