public RecurringTimeFrequency(int interval, IntervalUnit unit, TimeSpan startTime, TimeSpan endTime)
		{
			this.Interval = interval;
			this.Unit = unit;
			this.StartTime = startTime;
			this.EndTime = endTime;
		}

 /// <summary>
 /// Create a <see cref="CalendarIntervalTriggerImpl" /> that will occur immediately, and
 /// repeat at the the given interval.
 /// </summary>
 /// <param name="name">Name for the trigger instance.</param>
 /// <param name="intervalUnit">The repeat interval unit (minutes, days, months, etc).</param>
 /// <param name="repeatInterval">The number of milliseconds to pause between the repeat firing.</param>
 public CalendarIntervalTriggerImpl(string name, IntervalUnit intervalUnit, int repeatInterval)
     : this(name, null, intervalUnit, repeatInterval)
 {
 }

 private static DateTimeOffset TranslatedAdd(DateTimeOffset date, IntervalUnit unit, int amountToAdd)
 {
     switch (unit)
     {
         case IntervalUnit.Day:
             return date.AddDays(amountToAdd);
         case IntervalUnit.Hour:
             return date.AddHours(amountToAdd);
         case IntervalUnit.Minute:
             return date.AddMinutes(amountToAdd);
         case IntervalUnit.Month:
             return date.AddMonths(amountToAdd);
         case IntervalUnit.Second:
             return date.AddSeconds(amountToAdd);
         case IntervalUnit.Millisecond:
             return date.AddMilliseconds(amountToAdd);
         case IntervalUnit.Week:
             return date.AddDays(amountToAdd*7);
         case IntervalUnit.Year:
             return date.AddYears(amountToAdd);
         default:
             throw new ArgumentException("Unknown IntervalUnit");
     }
 }

 public static DateTimeOffset FutureDate(int interval, IntervalUnit unit)
 {
     return TranslatedAdd(SystemTime.Now(), unit, interval);
 }

 /// <summary>
 /// Create a <see cref="IDailyTimeIntervalTrigger" /> that will occur at the given time,
 /// fire the identified job and repeat at the given
 /// interval until the given end time.
 /// </summary>
 /// <param name="name"></param>
 /// <param name="group"></param>
 /// <param name="jobName"></param>
 /// <param name="jobGroup"></param>
 /// <param name="startTimeUtc">A <see cref="DateTimeOffset" /> set to the time for the <see cref="ITrigger" />to fire.</param>
 /// <param name="endTimeUtc">A <see cref="DateTimeOffset" /> set to the time for the <see cref="ITrigger" />to quit repeat firing.</param>
 /// <param name="startTimeOfDayUtc">The <see cref="TimeOfDay" /> that the repeating should begin occurring.</param>
 /// <param name="endTimeOfDayUtc">The <see cref="TimeOfDay" /> that the repeating should stop occurring.</param>
 /// <param name="intervalUnit">The repeat interval unit. The only intervals that are valid for this type of trigger are
 /// <see cref="IntervalUnit.Second"/>, <see cref="IntervalUnit.Minute"/>, and <see cref="IntervalUnit.Hour"/>.</param>
 /// <param name="repeatInterval">The number of milliseconds to pause between the repeat firing.</param>
 public DailyTimeIntervalTriggerImpl(string name, string group, string jobName,
                                     string jobGroup, DateTimeOffset startTimeUtc, DateTimeOffset? endTimeUtc,
                                     TimeOfDay startTimeOfDayUtc, TimeOfDay endTimeOfDayUtc,
                                     IntervalUnit intervalUnit, int repeatInterval)
     : base(name, group, jobName, jobGroup)
 {
     StartTimeUtc = startTimeUtc;
     EndTimeUtc = endTimeUtc;
     RepeatIntervalUnit = intervalUnit;
     RepeatInterval = repeatInterval;
     StartTimeOfDay = startTimeOfDayUtc;
     EndTimeOfDay = endTimeOfDayUtc;
 }

 public static DateTimeOffset DateAdd(DateTimeOffset timestamp, int interval, IntervalUnit intervalUnit)
 {
     throw Invalid();
 }

 public IProduct CreateProduct(int ProductFamilyID, string Name, string Handle, int PriceInCents, int Interval, IntervalUnit IntervalUnit, string AccountingCode, string Description)
 {
     throw new NotImplementedException();
 }

 /// <summary>
 /// Constructs a interval given an value in milliseconds
 /// </summary>
 public Interval(int value)
 {
     _value = value;
     _mode = IntervalUnit.Millisecond;
     AsTimeSpan = TimeSpan.FromMilliseconds(value);
 }