private static long millisecondsToTimeUnit(long milliseconds,int timeUnit){
switch (timeUnit) {
case TU_MILLISECONDS:
case TU_SECONDS:
case TU_MINUTES:
case TU_HOURS:
case TU_DAYS:
    return Math.abs(milliseconds) / timeUnit;
}
return -1;
}

private static long millisecondsToTimeUnit ( long milliseconds , int timeUnit ) { switch ( timeUnit ) { case TU_MILLISECONDS : case TU_SECONDS : case TU_MINUTES : case TU_HOURS : case TU_DAYS : return Math . abs ( milliseconds ) / timeUnit ; } return - 1 ; }
convert milliseconds to specific time unit
