Added SampleExpirationMilliseconds parameter. (petermetz#258)

Adjusting the averaging filter time

src/android/LocationManager.java

@@ -47,6 +47,8 @@ Licensed to the Apache Software Foundation (ASF) under one
 import org.altbeacon.beacon.MonitorNotifier;
 import org.altbeacon.beacon.RangeNotifier;
 import org.altbeacon.beacon.Region;
+import org.altbeacon.beacon.service.RunningAverageRssiFilter;
+import org.altbeacon.beacon.service.RangedBeacon;
 import org.apache.cordova.CallbackContext;
 import org.apache.cordova.CordovaInterface;
 import org.apache.cordova.CordovaPlugin;
@@ -72,6 +74,8 @@ public class LocationManager extends CordovaPlugin implements BeaconConsumer {
     private static final String FOREGROUND_BETWEEN_SCAN_PERIOD_NAME = "com.unarin.cordova.beacon.android.altbeacon.ForegroundBetweenScanPeriod";
     private static final String FOREGROUND_SCAN_PERIOD_NAME = "com.unarin.cordova.beacon.android.altbeacon.ForegroundScanPeriod";
     private static final int DEFAULT_FOREGROUND_BETWEEN_SCAN_PERIOD = 0;
+    private static final String SAMPLE_EXPIRATION_MILLISECOND = "com.unarin.cordova.beacon.android.altbeacon.SampleExpirationMilliseconds";
+    private static final int DEFAULT_SAMPLE_EXPIRATION_MILLISECOND = 20000;
     private static final int DEFAULT_FOREGROUND_SCAN_PERIOD = 200;
     private static int CDV_LOCATION_MANAGER_DOM_DELEGATE_TIMEOUT = 30;
     private static final int BUILD_VERSION_CODES_M = 23;
@@ -118,6 +122,16 @@ public void initialize(CordovaInterface cordova, CordovaWebView webView) {
         iBeaconManager.setForegroundBetweenScanPeriod(foregroundBetweenScanPeriod);
         iBeaconManager.setForegroundScanPeriod(foregroundScanPeriod);
 
+        final int sampleExpirationMilliseconds = this.preferences.getInteger(
+                SAMPLE_EXPIRATION_MILLISECOND, DEFAULT_SAMPLE_EXPIRATION_MILLISECOND);
+
+        Log.i(TAG, "Determined config value SAMPLE_EXPIRATION_MILLISECOND: " +
+                String.valueOf(sampleExpirationMilliseconds));
+
+        iBeaconManager.setRssiFilterImplClass(RunningAverageRssiFilter.class);        
+        RunningAverageRssiFilter.setSampleExpirationMilliseconds(sampleExpirationMilliseconds);
+        RangedBeacon.setSampleExpirationMilliseconds(sampleExpirationMilliseconds);
+
         initBluetoothListener();
         initEventQueue();
         pauseEventPropagationToDom(); // Before the DOM is loaded we'll just keep collecting the events and fire them later.