org.springframework.scheduling.support
Class CronSequenceGenerator

java.lang.Object
  org.springframework.scheduling.support.CronSequenceGenerator

public class CronSequenceGenerator
extends java.lang.Object

Date sequence generator for a Crontab pattern, allowing clients to specify a pattern that the sequence matches.

The pattern is a list of six single space-separated fields: representing second, minute, hour, day, month, weekday. Month and weekday names can be given as the first three letters of the English names.

Example patterns:

• "0 0 * * * *" = the top of every hour of every day.
• "*/10 * * * * *" = every ten seconds.
• "0 0 8-10 * * *" = 8, 9 and 10 o'clock of every day.
• "0 0/30 8-10 * * *" = 8:00, 8:30, 9:00, 9:30 and 10 o'clock every day.
• "0 0 9-17 * * MON-FRI" = on the hour nine-to-five weekdays
• "0 0 0 25 12 ?" = every Christmas Day at midnight

Since:

3.0

Author:

Dave Syer, Juergen Hoeller

See Also:

CronTrigger

Field Summary

private java.util.BitSet	daysOfMonth
private java.util.BitSet	daysOfWeek
private java.lang.String	expression
private java.util.BitSet	hours
private java.util.BitSet	minutes
private java.util.BitSet	months
private java.util.BitSet	seconds
private java.util.TimeZone	timeZone

Constructor Summary

CronSequenceGenerator(java.lang.String expression, java.util.TimeZone timeZone)
Construct a CronSequenceGenerator from the pattern provided.

Method Summary

private void	doNext(java.util.Calendar calendar, int dot)
boolean	equals(java.lang.Object obj)
private int	findNext(java.util.BitSet bits, int value, java.util.Calendar calendar, int field, int nextField, java.util.List<java.lang.Integer> lowerOrders) Search the bits provided for the next set bit after the value provided, and reset the calendar.
private int	findNextDay(java.util.Calendar calendar, java.util.BitSet daysOfMonth, int dayOfMonth, java.util.BitSet daysOfWeek, int dayOfWeek, java.util.List<java.lang.Integer> resets)
private int[]	getRange(java.lang.String field, int min, int max)
int	hashCode()
java.util.Date	next(java.util.Date date) Get the next Date in the sequence matching the Cron pattern and after the value provided.
private void	parse(java.lang.String expression) Parse the given pattern expression.
private java.lang.String	replaceOrdinals(java.lang.String value, java.lang.String commaSeparatedList) Replace the values in the commaSeparatedList (case insensitive) with their index in the list.
private void	reset(java.util.Calendar calendar, java.util.List<java.lang.Integer> fields) Reset the calendar setting all the fields provided to zero.
private void	setDays(java.util.BitSet bits, java.lang.String field, int max)
private void	setDaysOfMonth(java.util.BitSet bits, java.lang.String field)
private void	setMonths(java.util.BitSet bits, java.lang.String value)
private void	setNumberHits(java.util.BitSet bits, java.lang.String value, int min, int max)
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

seconds

private final java.util.BitSet seconds

minutes

private final java.util.BitSet minutes

hours

private final java.util.BitSet hours

daysOfWeek

private final java.util.BitSet daysOfWeek

daysOfMonth

private final java.util.BitSet daysOfMonth

months

private final java.util.BitSet months

expression

private final java.lang.String expression

timeZone

private final java.util.TimeZone timeZone

Constructor Detail

CronSequenceGenerator

public CronSequenceGenerator(java.lang.String expression,
                             java.util.TimeZone timeZone)

Construct a CronSequenceGenerator from the pattern provided.

Parameters:

expression - a space-separated list of time fields

timeZone - the TimeZone to use for generated trigger times

Throws:

java.lang.IllegalArgumentException - if the pattern cannot be parsed

Method Detail

next

public java.util.Date next(java.util.Date date)

Get the next Date in the sequence matching the Cron pattern and after the value provided. The return value will have a whole number of seconds, and will be after the input value.

Parameters:

date - a seed value

Returns:

the next value matching the pattern

doNext

private void doNext(java.util.Calendar calendar,
                    int dot)

findNextDay

private int findNextDay(java.util.Calendar calendar,
                        java.util.BitSet daysOfMonth,
                        int dayOfMonth,
                        java.util.BitSet daysOfWeek,
                        int dayOfWeek,
                        java.util.List<java.lang.Integer> resets)

findNext

private int findNext(java.util.BitSet bits,
                     int value,
                     java.util.Calendar calendar,
                     int field,
                     int nextField,
                     java.util.List<java.lang.Integer> lowerOrders)

Search the bits provided for the next set bit after the value provided, and reset the calendar.

Parameters:

bits - a BitSet representing the allowed values of the field

value - the current value of the field

calendar - the calendar to increment as we move through the bits

field - the field to increment in the calendar (@see Calendar for the static constants defining valid fields)

lowerOrders - the Calendar field ids that should be reset (i.e. the ones of lower significance than the field of interest)

Returns:

the value of the calendar field that is next in the sequence

reset

private void reset(java.util.Calendar calendar,
                   java.util.List<java.lang.Integer> fields)

Reset the calendar setting all the fields provided to zero.

parse

private void parse(java.lang.String expression)
            throws java.lang.IllegalArgumentException

Parse the given pattern expression.

Throws:

java.lang.IllegalArgumentException

replaceOrdinals

private java.lang.String replaceOrdinals(java.lang.String value,
                                         java.lang.String commaSeparatedList)

Replace the values in the commaSeparatedList (case insensitive) with their index in the list.

Returns:

a new string with the values from the list replaced

setDaysOfMonth

private void setDaysOfMonth(java.util.BitSet bits,
                            java.lang.String field)

setDays

private void setDays(java.util.BitSet bits,
                     java.lang.String field,
                     int max)

setMonths

private void setMonths(java.util.BitSet bits,
                       java.lang.String value)

setNumberHits

private void setNumberHits(java.util.BitSet bits,
                           java.lang.String value,
                           int min,
                           int max)

getRange

private int[] getRange(java.lang.String field,
                       int min,
                       int max)

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object