fc.cron

Class CronExpression

java.lang.Object

fc.cron.CronExpression

public class CronExpression
extends Object

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’

’?‘ Ca 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-sensitivt 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.Feltene evalueres Overlap of intervals are not allowed. That is: for Day-of-week field "FRI-MON" is invalid,but "FRI-SUN,MON" is valid

Constructor Summary

Constructors

Constructor and Description
CronExpression(String expr)
CronExpression(String expr, boolean withSeconds)

Method Summary

Modifier and Type	Method and Description
static CronExpression	create(String expr)
static CronExpression	createWithoutSeconds(String expr)
org.joda.time.DateTime	nextTimeAfter(org.joda.time.DateTime afterTime)
org.joda.time.DateTime	nextTimeAfter(org.joda.time.DateTime afterTime, org.joda.time.DateTime dateTimeBarrier)
org.joda.time.DateTime	nextTimeAfter(org.joda.time.DateTime afterTime, long durationInMillis)
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CronExpression

public CronExpression(String expr)

CronExpression

public CronExpression(String expr,
                      boolean withSeconds)

Method Detail

create

public static CronExpression create(String expr)

createWithoutSeconds

public static CronExpression createWithoutSeconds(String expr)

nextTimeAfter

public org.joda.time.DateTime nextTimeAfter(org.joda.time.DateTime afterTime)

nextTimeAfter

public org.joda.time.DateTime nextTimeAfter(org.joda.time.DateTime afterTime,
                                            long durationInMillis)

nextTimeAfter

public org.joda.time.DateTime nextTimeAfter(org.joda.time.DateTime afterTime,
                                            org.joda.time.DateTime dateTimeBarrier)

toString

public String toString()

Overrides:

toString in class Object