Thanks to Quartz project, https://quartz.dev.java.net
Provides a parser and evaluator for unix-like cron expressions. Cron
expressions provide the ability to specify complex time combinations such as
"At 8:00am every Monday through Friday" or "At 1:30am every
last Friday of the month".
Cron expressions are comprised of 6 required fields and one optional field
separated by white space. The fields respectively are described as follows:
Field Name
Allowed Values
Allowed Special Characters
Seconds
, - * /
Minutes
, - * /
Hours
, - * /
Day-of-month
, - * ? / L W
Month
1-12 or JAN-DEC
, - * /
Day-of-Week
1-7 or SUN-SAT
, - * ? / L #
Year (Optional)
empty, 1970-2099
, - * /
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 fileds, 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". When using the 'L' option, it
is important not to specify lists, or ranges of values, as you'll get
confusing 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.
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 on of these fields).
-
See Also:
-
Serialized Form
Time.CronExpression
(java.lang.String cronExpression)
Constructs a new
CronExpression
based on the specified
parameter.
protected java.lang.String
getExpressionSetSummary
(java.util.ArrayList<java.lang.Integer> list)
protected java.lang.String
getExpressionSetSummary
(java.util.Set<java.lang.Integer> set)
java.lang.String
getExpressionSummary
()
java.util.Date
getFinalFireTime
()
NOT YET IMPLEMENTED: Returns the final time that the
CronExpression
will match.
protected int
getLastDayOfMonth
(int monthNum,
int year)
protected int
getMonthNumber
(java.lang.String s)
getNextInterval
(java.util.Date date)
Return the interval between the next valid date and the one after
java.util.Date
getNextInvalidTimeAfter
(java.util.Date date)
Returns the next date/time
after
the given date/time which does
not
satisfy the expression
java.util.Date
getNextValidTimeAfter
(java.util.Date date)
Returns the next date/time
after
the given date/time which
satisfies the cron expression.
protected int
getNumericValue
(java.lang.String s,
int i)
protected java.util.TreeSet<java.lang.Integer>
getSet
(int type)
protected java.util.Date
getTimeAfter
(java.util.Date afterTime)
protected java.util.Date
getTimeBefore
(java.util.Date endTime)
NOT YET IMPLEMENTED: Returns the time before the given time
that the
CronExpression
matches.
java.util.TimeZone
getTimeZone
()
Returns the time zone for which this
CronExpression
will be resolved.
protected play.libs.Time.ValueSet
getValue
(int v,
java.lang.String s,
int i)
protected boolean
isLeapYear
(int year)
boolean
isSatisfiedBy
(java.util.Date date)
Indicates whether the given date satisfies the cron expression.
static boolean
isValidExpression
(java.lang.String cronExpression)
Indicates whether the specified cron expression can be parsed into a
valid cron expression
protected void
setCalendarHour
(java.util.Calendar cal,
int hour)
Advance the calendar to the particular hour paying particular attention
to daylight saving problems.
setTimeZone
(java.util.TimeZone timeZone)
Sets the time zone for which this
CronExpression
will be resolved.
protected int
skipWhiteSpace
(int i,
java.lang.String s)
protected int
storeExpressionVals
(int pos,
java.lang.String s,
int type)
java.lang.String
toString
()
Returns the string representation of the
CronExpression
Time.CronExpression
public Time.CronExpression(java.lang.String cronExpression)
throws java.text.ParseException
Constructs a new
CronExpression
based on the specified
parameter.
-
Parameters:
-
cronExpression
- String representation of the cron expression the
new object should represent
-
Throws:
-
java.text.ParseException
- if the string expression cannot be parsed into a valid
CronExpression
isSatisfiedBy
public boolean isSatisfiedBy(java.util.Date date)
Indicates whether the given date satisfies the cron expression. Note that
milliseconds are ignored, so two Dates falling on different milliseconds
of the same second will always have the same result here.
-
Parameters:
-
date
- the date to evaluate
-
Returns:
-
a boolean indicating whether the given date satisfies the cron
expression
getNextValidTimeAfter
public java.util.Date getNextValidTimeAfter(java.util.Date date)
Returns the next date/time
after
the given date/time which
satisfies the cron expression.
-
Parameters:
-
date
- the date/time at which to begin the search for the next valid
date/time
-
Returns:
-
the next valid date/time
getNextInvalidTimeAfter
public java.util.Date getNextInvalidTimeAfter(java.util.Date date)
Returns the next date/time
after
the given date/time which does
not
satisfy the expression
-
Parameters:
-
date
- the date/time at which to begin the search for the next
invalid date/time
-
Returns:
-
the next valid date/time
getNextInterval
public long getNextInterval(java.util.Date date)
Return the interval between the next valid date and the one after
-
Parameters:
-
date
- the date/time at which to begin the search
-
Returns:
-
the number of milliseconds between the next valid and the one after
getTimeZone
public java.util.TimeZone getTimeZone()
Returns the time zone for which this
CronExpression
will be resolved.
setTimeZone
public void setTimeZone(java.util.TimeZone timeZone)
Sets the time zone for which this
CronExpression
will be resolved.
toString
public java.lang.String toString()
Returns the string representation of the
CronExpression
Overrides:
toString
in class
java.lang.Object
Returns:
a string representation of the
CronExpression
isValidExpression
public static boolean isValidExpression(java.lang.String cronExpression)
Indicates whether the specified cron expression can be parsed into a
valid cron expression
-
Parameters:
-
cronExpression
- the expression to evaluate
-
Returns:
-
a boolean indicating whether the given expression is a valid cron
expression
buildExpression
protected void buildExpression(java.lang.String expression)
throws java.text.ParseException
-
Throws:
-
java.text.ParseException
protected void setCalendarHour(java.util.Calendar cal,
int hour)
Advance the calendar to the particular hour paying particular attention
to daylight saving problems.
-
Parameters:
-
cal
-
-
hour
-
getTimeBefore
protected java.util.Date getTimeBefore(java.util.Date endTime)
NOT YET IMPLEMENTED: Returns the time before the given time
that the
CronExpression
matches.
getFinalFireTime
public java.util.Date getFinalFireTime()
NOT YET IMPLEMENTED: Returns the final time that the
CronExpression
will match.