CronExpression Class

[SerializableAttribute]
public class CronExpression : IDeserializationCallback, 
	ISerializable

The CronExpression type exposes the following members.

	Name	Description
	CronExpression(String)	Constructs a new CronExpressionString based on the specified parameter.
	CronExpression(SerializationInfo, StreamingContext)	Serialization constructor.

	Name	Description
	CronExpressionString	Gets the cron expression string.
	TimeZone	Sets or gets the time zone for which the CronExpression of this ICronTrigger will be resolved.

	Name	Description
	AddToSet	Adds to set.
	BuildExpression	Builds the expression.
	CheckNext	Checks the next value.
	Clone	Creates a new object that is a copy of the current instance.
	CreateDateTimeWithoutMillis	Creates the date time without milliseconds.
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Overrides ObjectEquals(Object).)
	Equals(CronExpression)	Determines whether the specified CronExpression is equal to the current CronExpression.
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	FindNextWhiteSpace	Finds the next white space.
	GetDayOfWeekNumber	Gets the day of week number.
	GetExpressionSetSummary	Gets the expression set summary.
	GetExpressionSummary	Gets the expression summary.
	GetFinalFireTime	NOT YET IMPLEMENTED: Returns the final time that the CronExpression will match.
	GetHashCode	Serves as a hash function for a particular type. (Overrides ObjectGetHashCode.)
	GetLastDayOfMonth	Gets the last day of month.
	GetMonthNumber	Gets the month number.
	GetNextInvalidTimeAfter	Returns the next date/time after the given date/time which does not satisfy the expression.
	GetNextValidTimeAfter	Returns the next date/time after the given date/time which satisfies the cron expression.
	GetNumericValue	Gets the numeric value from string.
	GetObjectData
	GetSet	Gets the set of given type.
	GetTime	Gets the time from given time parts.
	GetTimeAfter	Gets the next fire time after the given time.
	GetTimeBefore	Gets the time before.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetValue	Gets the value.
	IsLeapYear	Determines whether given year is a leap year.
	IsSatisfiedBy	Indicates whether the given date satisfies the cron expression.
	IsValidExpression	Indicates whether the specified cron expression can be parsed into a valid cron expression
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnDeserialization
	SetCalendarHour	Advance the calendar to the particular hour paying particular attention to daylight saving problems.
	SkipWhiteSpace	Skips the white space.
	StoreExpressionVals	Stores the expression values.
	ToString	Returns the string representation of the CronExpression (Overrides ObjectToString.)
	ValidateExpression

	Name	Description
	AllSpec	Field specification for wildcard '*'.
	AllSpecInt	Field specification for all wildcard value '*'.
	calendardayOfMonth	Calendar day of month.
	calendardayOfWeek	Calendar day of week.
	DayOfMonth	Field specification for day of month.
	DayOfWeek	Field specification for day of week.
	daysOfMonth	Days of month.
	daysOfWeek	Days of week.
	expressionParsed	Expression parsed.
	Hour	Field specification for hour.
	hours	Hours.
	lastdayOffset
	lastdayOfMonth	Last day of month.
	lastdayOfWeek	Last day of week.
	MaxYear
	Minute	Field specification for minute.
	minutes	minutes.
	Month	Field specification for month.
	months	Months.
	nearestWeekday	Nearest weekday.
	NoSpec	Field specification for no specification at all '?'.
	NoSpecInt	Field specification for not specified value '?'.
	nthdayOfWeek	Nth day of week.
	Second	Field specification for second.
	seconds	Seconds.
	Year	Field specification for year.
	years	Years.

Cron expressions are comprised of 6 required fields and one optional field separated by white space. The fields respectively are described as follows:

The '*' character is used to specify all values. For example, "*" in the minute field means "every minute".

The '?' character is allowed for the day-of-month and day-of-week fields. It is used to specify 'no specific value'. This is useful when you need to specify something in one of the two fields, but not the other.

The '-' character is used to specify ranges For example "10-12" in the hour field means "the hours 10, 11 and 12".

The ',' character is used to specify additional values. For example "MON,WED,FRI" in the day-of-week field means "the days Monday, Wednesday, and Friday".

The '/' character is used to specify increments. For example "0/15" in the seconds field means "the seconds 0, 15, 30, and 45". And "5/15" in the seconds field means "the seconds 5, 20, 35, and 50". Specifying '*' before the '/' is equivalent to specifying 0 is the value to start with. Essentially, for each field in the expression, there is a set of numbers that can be turned on or off. For seconds and minutes, the numbers range from 0 to 59. For hours 0 to 23, for days of the month 0 to 31, and for months 1 to 12. The "/" character simply helps you turn on every "nth" value in the given set. Thus "7/6" in the month field only turns on month "7", it does NOT mean every 6th month, please note that subtlety.

The 'L' character is allowed for the day-of-month and day-of-week fields. This character is short-hand for "last", but it has different meaning in each of the two fields. For example, the value "L" in the day-of-month field means "the last day of the month" - day 31 for January, day 28 for February on non-leap years. If used in the day-of-week field by itself, it simply means "7" or "SAT". But if used in the day-of-week field after another value, it means "the last xxx day of the month" - for example "6L" means "the last friday of the month". You can also specify an offset from the last day of the month, such as "L-3" which would mean the third-to-last day of the calendar month. When using the 'L' option, it is important not to specify lists, or ranges of values, as you'll get confusing/unexpected results.

The 'W' character is allowed for the day-of-month field. This character is used to specify the weekday (Monday-Friday) nearest the given day. As an example, if you were to specify "15W" as the value for the day-of-month field, the meaning is: "the nearest weekday to the 15th of the month". So if the 15th is a Saturday, the trigger will fire on Friday the 14th. If the 15th is a Sunday, the trigger will fire on Monday the 16th. If the 15th is a Tuesday, then it will fire on Tuesday the 15th. However if you specify "1W" as the value for day-of-month, and the 1st is a Saturday, the trigger will fire on Monday the 3rd, as it will not 'jump' over the boundary of a month's days. The 'W' character can only be specified when the day-of-month is a single day, not a range or list of days.

The 'L' and 'W' characters can also be combined for the day-of-month expression to yield 'LW', which translates to "last weekday of the month".

The '#' character is allowed for the day-of-week field. This character is used to specify "the nth" XXX day of the month. For example, the value of "6#3" in the day-of-week field means the third Friday of the month (day 6 = Friday and "#3" = the 3rd one in the month). Other examples: "2#1" = the first Monday of the month and "4#5" = the fifth Wednesday of the month. Note that if you specify "#5" and there is not 5 of the given day-of-week in the month, then no firing will occur that month. If the '#' character is used, there can only be one expression in the day-of-week field ("3#1,6#3" is not valid, since there are two expressions).

The legal characters and the names of months and days of the week are not case sensitive.

NOTES:

• Support for specifying both a day-of-week and a day-of-month value is not complete (you'll need to use the '?' character in one of these fields).
• Overflowing ranges is supported - that is, having a larger number on the left hand side than the right. You might do 22-2 to catch 10 o'clock at night until 2 o'clock in the morning, or you might have NOV-FEB. It is very important to note that overuse of overflowing ranges creates ranges that don't make sense and no effort has been made to determine which interpretation CronExpression chooses. An example would be "0 0 14-6 ? * FRI-MON".

Reference