Regression in custom sample expiration for RunningAverageRssiFilter

[cupakromer]

Expected behavior

Setting a custom sample expiration using RunningAverageRssiFilter. setSampleExpirationMilliseconds changes the static expiration and thus running RSSI averages.

Actual behavior

All distance calculations use the value from RangedBeacon.sampleExpirationMilliseconds.

This is a regression of #523 (AltBeacon/android-beacon-library-reference#30). It was introduced in commit f084042 (PR #484) where the RunningAverageRssiFilter has it's value constantly reset after every cycle in RangedBeacon#commitMeasurements.

Steps to reproduce this behavior

1. Set a custom sample expiration through RunningAverageRssiFilter.setSampleExpirationMilliseconds
2. Range for a beacon
3. Wait for the scan cycle to complete
4. Check the value of the RunningAverageRssiFilter sample expiration

Android Beacon Library version

2.12.3

[davidgyoung]

Yes, it appears I undid the change from #523 got undone in a bad merge.

I think it is safe to remove the sampleExpirationMilliseconds field from RangedBeacon entirely, including its use in commitMeasurements(). This field is a holdover from the 0.x version of the library where RangedBeacon was where this setting was stored. Only this method needs to be retained:

    //kept here for backward compatibility
    public static void setSampleExpirationMilliseconds(long milliseconds) {
        sampleExpirationMilliseconds = milliseconds;
        RunningAverageRssiFilter.setSampleExpirationMilliseconds(sampleExpirationMilliseconds);
    }

And it should probably be deprecated.