class TimeUtil {
    /**
     * Return the number of milliseconds per time unit.
     *
     * @param timeUnit TimeUnit
     * @return long
     */
    public static long oneTimeUnitMillisecond(TimeUnit timeUnit) {<FILL_FUNCTION_BODY>}

    /**
     * Get the rounded-up timestamp in millisecond by the TimeUnit based on a start time.
     * @param timeUnit TimeUnit
     * @param start start time in millisecond
     * @return the next rounded up millisecond for the TimeUnit.
     */
    public static long nextStartTimestamp(TimeUnit timeUnit, long start) {
        long nextTimestamp = start;
        switch (timeUnit) {
            case MILLISECONDS:
                break;

            case SECONDS:
                nextTimestamp = 1000 + 1000 * (start / 1000); // the next second is the start timestamp.
                break;

            case MINUTES:
                nextTimestamp = 60000 + 60000 * (start / 60000); // next minute is the start timestamp
                break;

            case HOURS:
                nextTimestamp = 3600000 + 3600000 * (start / 3600000); // next hour is the start timestamp
                break;

            case DAYS:
                nextTimestamp = 86400000 + 86400000 * (start / 86400000); // next day is the start timestamp
                break;
        }
        return nextTimestamp;
    }

}

        long millisecond = 0;
        switch (timeUnit) {
            case MILLISECONDS:
                millisecond = 1;
                break;

            case SECONDS:
                millisecond = 1000;
                break;

            case MINUTES:
                millisecond = 60000;
                break;

            case HOURS:
                millisecond = 3600000;
                break;

            case DAYS:
                millisecond = 86400000;
                break;
        }
        return millisecond;
    
<no_super_class>