Added running average for RSSI

library/src/uk/co/alt236/bluetoothlelib/device/BluetoothLeDevice.java

@@ -1,10 +1,15 @@
 package uk.co.alt236.bluetoothlelib.device;
 
+import java.io.Serializable;
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
 
 import uk.co.alt236.bluetoothlelib.device.adrecord.AdRecordStore;
 import uk.co.alt236.bluetoothlelib.util.AdRecordUtils;
 import uk.co.alt236.bluetoothlelib.util.ByteUtils;
+import uk.co.alt236.bluetoothlelib.util.LimitedLinkHashMap;
 import android.bluetooth.BluetoothClass;
 import android.bluetooth.BluetoothDevice;
 import android.os.Bundle;
@@ -20,16 +25,25 @@ import android.os.Parcelable;
  */
 public class BluetoothLeDevice implements Parcelable{
 	private static final String PARCEL_EXTRA_BLUETOOTH_DEVICE = "bluetooth_device";
-	private static final String PARCEL_EXTRA_DEVICE_RSSI = "device_rssi";
+	private static final String PARCEL_EXTRA_CURRENT_RSSI = "current_rssi";
+	private static final String PARCEL_EXTRA_CURRENT_TIMESTAMP = "current_timestamp";
+	private static final String PARCEL_EXTRA_DEVICE_RSSI_LOG = "device_rssi_log";
 	private static final String PARCEL_EXTRA_DEVICE_SCANRECORD = "device_scanrecord";
 	private static final String PARCEL_EXTRA_DEVICE_SCANRECORD_STORE = "device_scanrecord_store";
-	private static final String PARCEL_EXTRA_TIMESTAMP = "timestamp";
+	private static final String PARCEL_EXTRA_FIRST_RSSI = "device_first_rssi";
+	private static final String PARCEL_EXTRA_FIRST_TIMESTAMP = "first_timestamp";
+
+	private static final int MAX_RSSI_LOG_SIZE = 10;
+	private static final long LOG_INVALIDATION_THRESHOLD = 10 * 1000;
 
 	private final AdRecordStore mRecordStore;
 	private final BluetoothDevice mDevice;
+	private final Map<Long, Integer> mRssiLog;
 	private final byte[] mScanRecord;
-	private final int mRssi;
+	private final int mFirstRssi;
-	private final long mTimestamp;
+	private final long mFirstTimestamp;
+	private int mCurrentRssi;
+	private long mCurrentTimestamp;
 
 	public static final Parcelable.Creator<BluetoothLeDevice> CREATOR = new Parcelable.Creator<BluetoothLeDevice>() {
 		public BluetoothLeDevice createFromParcel(Parcel in) {
@@ -40,29 +54,60 @@ public class BluetoothLeDevice implements Parcelable{
 			return new BluetoothLeDevice[size];
 		}
 	};
-	
-	public BluetoothLeDevice(BluetoothDevice device, int rssi, byte[] scanRecord){
-		this(device, rssi, scanRecord, 0);
-	}
 
 	public BluetoothLeDevice(BluetoothDevice device, int rssi, byte[] scanRecord, long timestamp){
 		mDevice = device;
-		mRssi = rssi;
+		mFirstRssi = rssi;
-		mScanRecord = scanRecord;
+		mFirstTimestamp = timestamp;
 		mRecordStore = new AdRecordStore(AdRecordUtils.parseScanRecordAsSparseArray(scanRecord));
-		mTimestamp = timestamp;
+		mScanRecord = scanRecord;
+		mRssiLog = Collections.synchronizedMap(
+				new LimitedLinkHashMap<Long, Integer>(MAX_RSSI_LOG_SIZE));
+		updateRssiReading(timestamp, rssi);
 	}
 
+	public double getRunningAverageRssi(){
+		final Collection<Integer> values = mRssiLog.values();
+		int sum = 0;
+
+		for(Integer value: values){
+			sum += value.intValue();
+		}
+
+		return sum/values.size();
+	}
+
+	@SuppressWarnings("unchecked")
 	protected BluetoothLeDevice(Parcel in) {
 		final Bundle b = in.readBundle(getClass().getClassLoader());
 
+		mCurrentRssi = b.getInt(PARCEL_EXTRA_CURRENT_RSSI, 0);
+		mCurrentTimestamp = b.getLong(PARCEL_EXTRA_CURRENT_TIMESTAMP, 0);
 		mDevice = b.getParcelable(PARCEL_EXTRA_BLUETOOTH_DEVICE);
+		mFirstRssi = b.getInt(PARCEL_EXTRA_FIRST_RSSI, 0);
+		mFirstTimestamp = b.getLong(PARCEL_EXTRA_FIRST_TIMESTAMP, 0);
 		mRecordStore = b.getParcelable(PARCEL_EXTRA_DEVICE_SCANRECORD_STORE);
-		mRssi = b.getInt(PARCEL_EXTRA_DEVICE_RSSI, 0);
 		mScanRecord = b.getByteArray(PARCEL_EXTRA_DEVICE_SCANRECORD);
-		mTimestamp = b.getLong(PARCEL_EXTRA_TIMESTAMP, 0);
+
+		mRssiLog = Collections.synchronizedMap(
+				(Map<Long, Integer>) b.getSerializable(PARCEL_EXTRA_DEVICE_RSSI_LOG));
     }
 
+	public synchronized void updateRssiReading(long timestamp, int rssiReading){
+		addToRssiLog(timestamp, rssiReading);
+	}
+
+	private void addToRssiLog(long timestamp, int rssiReading){
+
+		if(timestamp - mCurrentTimestamp > LOG_INVALIDATION_THRESHOLD){
+			mRssiLog.clear();
+		}
+
+		mCurrentRssi = rssiReading;
+		mCurrentTimestamp = timestamp;
+		mRssiLog.put(timestamp, rssiReading);
+	}
+
 	@Override
 	public int describeContents() {
 		return 0;
@@ -77,11 +122,29 @@ public class BluetoothLeDevice implements Parcelable{
 		if (getClass() != obj.getClass())
 			return false;
 		BluetoothLeDevice other = (BluetoothLeDevice) obj;
+		if (mCurrentRssi != other.mCurrentRssi)
+			return false;
+		if (mCurrentTimestamp != other.mCurrentTimestamp)
+			return false;
 		if (mDevice == null) {
 			if (other.mDevice != null)
 				return false;
 		} else if (!mDevice.equals(other.mDevice))
 			return false;
+		if (mFirstRssi != other.mFirstRssi)
+			return false;
+		if (mFirstTimestamp != other.mFirstTimestamp)
+			return false;
+		if (mRecordStore == null) {
+			if (other.mRecordStore != null)
+				return false;
+		} else if (!mRecordStore.equals(other.mRecordStore))
+			return false;
+		if (mRssiLog == null) {
+			if (other.mRssiLog != null)
+				return false;
+		} else if (!mRssiLog.equals(other.mRssiLog))
+			return false;
 		if (!Arrays.equals(mScanRecord, other.mScanRecord))
 			return false;
 		return true;
@@ -107,12 +170,20 @@ public class BluetoothLeDevice implements Parcelable{
 		return mDevice;
 	}
 
+	public int getFirstRssi(){
+		return mFirstRssi;
+	}
+
+	public long getFirstTimestamp(){
+		return mFirstTimestamp;
+	}
+
 	public String getName(){
 		return mDevice.getName();
 	}
 
 	public int getRssi() {
-		return mRssi;
+		return mCurrentRssi;
 	}
 
 	public byte[] getScanRecord() {
@@ -120,21 +191,27 @@ public class BluetoothLeDevice implements Parcelable{
 	}
 
 	public long getTimestamp(){
-		return mTimestamp;
+		return mCurrentTimestamp;
 	}
 
 	@Override
 	public int hashCode() {
 		final int prime = 31;
 		int result = 1;
+		result = prime * result + mCurrentRssi;
+		result = prime * result + (int) (mCurrentTimestamp ^ (mCurrentTimestamp >>> 32));
 		result = prime * result + ((mDevice == null) ? 0 : mDevice.hashCode());
+		result = prime * result + mFirstRssi;
+		result = prime * result + (int) (mFirstTimestamp ^ (mFirstTimestamp >>> 32));
+		result = prime * result + ((mRecordStore == null) ? 0 : mRecordStore.hashCode());
+		result = prime * result + ((mRssiLog == null) ? 0 : mRssiLog.hashCode());
 		result = prime * result + Arrays.hashCode(mScanRecord);
 		return result;
 	}
 
 	@Override
 	public String toString() {
-		return "BluetoothLeDevice [mDevice=" + mDevice + ", mRssi=" + mRssi + ", mScanRecord=" + ByteUtils.byteArrayToHexString(mScanRecord) + ", mRecordStore=" + mRecordStore + ", getBluetoothDeviceBondState()=" + getBluetoothDeviceBondState() + ", getBluetoothDeviceClassName()=" + getBluetoothDeviceClassName() + "]";
+		return "BluetoothLeDevice [mDevice=" + mDevice + ", mRssi=" + mFirstRssi + ", mScanRecord=" + ByteUtils.byteArrayToHexString(mScanRecord) + ", mRecordStore=" + mRecordStore + ", getBluetoothDeviceBondState()=" + getBluetoothDeviceBondState() + ", getBluetoothDeviceClassName()=" + getBluetoothDeviceClassName() + "]";
 	}
 
 	@Override
@@ -142,10 +219,16 @@ public class BluetoothLeDevice implements Parcelable{
 		final Bundle b = new Bundle(getClass().getClassLoader());
 
 		b.putByteArray(PARCEL_EXTRA_DEVICE_SCANRECORD, mScanRecord);
-		b.putInt(PARCEL_EXTRA_DEVICE_RSSI, mRssi);
+
-		b.putLong(PARCEL_EXTRA_TIMESTAMP, mTimestamp);
+		b.putInt(PARCEL_EXTRA_FIRST_RSSI, mFirstRssi);
+		b.putInt(PARCEL_EXTRA_CURRENT_RSSI, mCurrentRssi);
+
+		b.putLong(PARCEL_EXTRA_FIRST_TIMESTAMP, mFirstTimestamp);
+		b.putLong(PARCEL_EXTRA_CURRENT_TIMESTAMP, mCurrentTimestamp);
+
 		b.putParcelable(PARCEL_EXTRA_BLUETOOTH_DEVICE, mDevice);
 		b.putParcelable(PARCEL_EXTRA_DEVICE_SCANRECORD_STORE, mRecordStore);
+		b.putSerializable(PARCEL_EXTRA_DEVICE_RSSI_LOG, (Serializable) mRssiLog);
 
 		parcel.writeBundle(b);
 	}

library/src/uk/co/alt236/bluetoothlelib/device/IBeaconDevice.java

@@ -8,7 +8,7 @@ import android.os.Parcel;
 
 public class IBeaconDevice extends BluetoothLeDevice{
 	private final IBeaconManufacturerData mIBeaconData;
-	
+
 	public IBeaconDevice(BluetoothDevice device, int rssi, byte[] scanRecord) {
 		super(device, rssi, scanRecord, 0);
 		mIBeaconData = new IBeaconManufacturerData(this);
@@ -22,40 +22,42 @@ public class IBeaconDevice extends BluetoothLeDevice{
 	public IBeaconDevice(BluetoothLeDevice device){
 		this(device.getDevice(), device.getRssi(), device.getScanRecord(), device.getTimestamp());
 	}
-	
+
 	private IBeaconDevice(Parcel in) {
 		super(in);
 		mIBeaconData = new IBeaconManufacturerData(this);
 	}
-	
+
 	public double getAccuracy(){
-		return IBeaconUtils.calculateAccuracy(getCalibratedTxPower(), getRssi());
+		return IBeaconUtils.calculateAccuracy(
+				getCalibratedTxPower(),
+				getRunningAverageRssi());
 	}
-	
+
 	public int getCalibratedTxPower(){
 		return getIBeaconData().getCalibratedTxPower();
 	}
-	
+
 	public int getCompanyIdentifier(){
 		return getIBeaconData().getCompanyIdentifier();
 	}
-	
+
 	public IBeaconDistanceDescriptor getDistanceDescriptor(){
 		return IBeaconUtils.getDistanceDescriptor(getAccuracy());
 	}
-	
+
 	public IBeaconManufacturerData getIBeaconData(){
 		return mIBeaconData;
 	}
-	
+
 	public int getMajor(){
 		return getIBeaconData().getMajor();
 	}
-	
+
 	public int getMinor(){
 		return getIBeaconData().getMinor();
 	}
-	
+
 	public String getUUID(){
 		return getIBeaconData().getUUID();
 	}

library/src/uk/co/alt236/bluetoothlelib/util/LimitedLinkHashMap.java

@@ -0,0 +1,20 @@
+package uk.co.alt236.bluetoothlelib.util;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class LimitedLinkHashMap<K, V> extends LinkedHashMap<K, V>{
+	private static final long serialVersionUID = -5375660288461724925L;
+
+	private final int mMaxSize;
+	public LimitedLinkHashMap(int maxSize){
+		super();
+		mMaxSize = maxSize;
+	}
+
+    @Override
+    protected boolean removeEldestEntry(Map.Entry<K, V> eldest)
+    {
+       return this.size() > mMaxSize;
+    }
+}