Package org.redisson.executor

Class CronExpression

  • public class CronExpression
extends Object
    This provides cron support for java8 using java-time.

    Parser for unix-like cron expressions: Cron expressions allow specifying combinations of criteria for time such as: "Each Monday-Friday at 08:00" or "Every last friday of the month at 01:30"

    A cron expressions consists of 5 or 6 mandatory fields (seconds may be omitted) separated by space.
    These are:

    Field   Allowable values   Special Characters
    Seconds (may be omitted)   0-59   , - * /
    Minutes   0-59   , - * /
    Hours   0-23   , - * /
    Day of month   1-31   , - * ? / L W
    Month   1-12 or JAN-DEC (note: english abbreviations)   , - * /
    Day of week   1-7 or MON-SUN (note: english abbreviations)   , - * ? / L #

    '*' Can be used in all fields and means 'for all values'. E.g. "*" in minutes, means 'for all minutes'

    '?' Can be used in Day-of-month and Day-of-week fields. Used to signify 'no special value'. It is used when one want to specify something for one of those two fields, but not the other.

    '-' Used to specify a time interval. E.g. "10-12" in Hours field means 'for hours 10, 11 and 12'

    ',' Used to specify multiple values for a field. E.g. "MON,WED,FRI" in Day-of-week field means "for monday, wednesday and friday"

    '/' Used to specify increments. E.g. "0/15" in Seconds field means "for seconds 0, 15, 30, ad 45". And "5/15" in seconds field means "for seconds 5, 20, 35, and 50". If '*' s specified before '/' it is the same as saying it starts at 0. For every field there's a list of values that can be turned on or off. For Seconds and Minutes these range from 0-59. For Hours from 0 to 23, For Day-of-month it's 1 to 31, For Months 1 to 12. "/" character helsp turn some of these values back on. Thus "7/6" in Months field specify just Month 7. It doesn't turn on every 6 month following, since cron fields never roll over

    'L' Can be used on Day-of-month and Day-of-week fields. It signifies last day of the set of allowed values. In Day-of-month field it's the last day of the month (e.g.. 31 jan, 28 feb (29 in leap years), 31 march, etc.). In Day-of-week field it's Sunday. If there's a prefix, this will be subtracted (5L in Day-of-month means 5 days before last day of Month: 26 jan, 23 feb, etc.)

    'W' Can be specified in Day-of-Month field. It specifies closest weekday (monday-friday). Holidays are not accounted for. "15W" in Day-of-Month field means 'closest weekday to 15 i in given month'. If the 15th is a Saturday, it gives Friday. If 15th is a Sunday, the it gives following Monday.

    '#' Can be used in Day-of-Week field. For example: "5#3" means 'third friday in month' (day 5 = friday, #3 - the third). If the day does not exist (e.g. "5#5" - 5th friday of month) and there aren't 5 fridays in the month, then it won't match until the next month with 5 fridays.

    Case-sensitive No fields are case-sensitive

    Dependencies between fields Fields are always evaluated independently, but the expression doesn't match until the constraints of each field are met. Overlap of intervals are not allowed. That is: for Day-of-week field "FRI-MON" is invalid,but "FRI-SUN,MON" is valid