question: private void update ( boolean forced ) { long now = System . currentTimeMillis ( ) ; long diff = now - this . lastUpdateRt ; double dur = ( now - startTime ) / 1000.0 ; if ( forced || ( diff > UI_UP_INTERVAL ) ) { double ssps = ( ( SimClock . getTime ( ) - lastUpdate ) * 1000 ) / diff ; print ( String . format ( "%.1f %d: %.2f 1/s" , dur , SimClock . getIntTime ( ) , ssps ) ) ; this . lastUpdateRt = System . currentTimeMillis ( ) ; this . lastUpdate = SimClock . getTime ( ) ; } }
target:  Updates user interface if the long enough (real)time (update interval) has passed from the previous update.