question: public synchronized void update ( double sample ) { long now = System . currentTimeMillis ( ) ; if ( lastMillis == 0 ) { average = sample ; lastMillis = now ; return ; } long deltaTime = now - lastMillis ; double coeff = Math . exp ( - 1.0 * ( ( double ) deltaTime / windowMillis ) ) ; average = ( 1.0 - coeff ) * sample + coeff * average ; lastMillis = now ; }
target:  Updates the average with the latest measurement.