org.quartz
Class CronExpression

java.lang.Object  extended by org.quartz.CronExpression
All Implemented Interfaces:
Serializable, Cloneable

public class CronExpression
extends Object
implements Serializable, Cloneable

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   0-59   , - * /
Minutes   0-59   , - * /
Hours   0-23   , - * /
Day-of-month   1-31   , - * ? / L W
Month   1-12 or JAN-DEC   , - * /
Day-of-Week   1-7 or SUN-SAT   , - * ? / L #
Year (Optional)   empty, 1970-2199   , - * /

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". 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. 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".

Author:
Sharada Jambula, James House, Contributions from Mads Henderson, Refactoring from CronTrigger to CronExpression by Aaron Craven
See Also:
Serialized Form


Field Summary
protected static IntegerALL_SPEC
           
protected static intALL_SPEC_INT
           
protected static intDAY_OF_MONTH
           
protected static intDAY_OF_WEEK
           
protected static MapdayMap
           
protected  TreeSetdaysOfMonth
           
protected  TreeSetdaysOfWeek
           
protected  booleanexpressionParsed
           
protected static intHOUR
           
protected  TreeSethours
           
protected  booleanlastdayOfMonth
           
protected  booleanlastdayOfWeek
           
protected static intMINUTE
           
protected  TreeSetminutes
           
protected static intMONTH
           
protected static MapmonthMap
           
protected  TreeSetmonths
           
protected  booleannearestWeekday
           
protected static IntegerNO_SPEC
           
protected static intNO_SPEC_INT
           
protected  intnthdayOfWeek
           
protected static intSECOND
           
protected  TreeSetseconds
           
protected static intYEAR
           
protected  TreeSetyears
           
 
Constructor Summary
CronExpression(String cronExpression)
          Constructs a new CronExpression based on the specified parameter.
 
Method Summary
protected  voidaddToSet(int val, int end, int incr, int type)
           
protected  voidbuildExpression(String expression)
           
protected  intcheckNext(int pos, String s, int val, int type)
           
 Objectclone()
           
protected  intfindNextWhiteSpace(int i, String s)
           
 StringgetCronExpression()
           
protected  intgetDayOfWeekNumber(String s)
           
protected  StringgetExpressionSetSummary(ArrayList list)
           
protected  StringgetExpressionSetSummary(Set set)
           
 StringgetExpressionSummary()
           
 DategetFinalFireTime()
          NOT YET IMPLEMENTED: Returns the final time that the CronExpression will match.
protected  intgetLastDayOfMonth(int monthNum, int year)
           
protected  intgetMonthNumber(String s)
           
 DategetNextInvalidTimeAfter(Date date)
          Returns the next date/time after the given date/time which does not satisfy the expression
 DategetNextValidTimeAfter(Date date)
          Returns the next date/time after the given date/time which satisfies the cron expression.
protected  intgetNumericValue(String s, int i)
           
protected  TreeSetgetSet(int type)
           
protected  DategetTimeAfter(Date afterTime)
           
protected  DategetTimeBefore(Date endTime)
          NOT YET IMPLEMENTED: Returns the time before the given time that the CronExpression matches.
 TimeZonegetTimeZone()
          Returns the time zone for which this CronExpression will be resolved.
protected  org.quartz.ValueSetgetValue(int v, String s, int i)
           
protected  booleanisLeapYear(int year)
           
 booleanisSatisfiedBy(Date date)
          Indicates whether the given date satisfies the cron expression.
static booleanisValidExpression(String cronExpression)
          Indicates whether the specified cron expression can be parsed into a valid cron expression
protected  voidsetCalendarHour(Calendar cal, int hour)
          Advance the calendar to the particular hour paying particular attention to daylight saving problems.
 voidsetTimeZone(TimeZone timeZone)
          Sets the time zone for which this CronExpression will be resolved.
protected  intskipWhiteSpace(int i, String s)
           
protected  intstoreExpressionVals(int pos, String s, int type)
           
 StringtoString()
          Returns the string representation of the CronExpression
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

SECOND

protected static final int SECOND
See Also:
Constant Field Values

MINUTE

protected static final int MINUTE
See Also:
Constant Field Values

HOUR

protected static final int HOUR
See Also:
Constant Field Values

DAY_OF_MONTH

protected static final int DAY_OF_MONTH
See Also:
Constant Field Values

MONTH

protected static final int MONTH
See Also:
Constant Field Values

DAY_OF_WEEK

protected static final int DAY_OF_WEEK
See Also:
Constant Field Values

YEAR

protected static final int YEAR
See Also:
Constant Field Values

ALL_SPEC_INT

protected static final int ALL_SPEC_INT
See Also:
Constant Field Values

NO_SPEC_INT

protected static final int NO_SPEC_INT
See Also:
Constant Field Values

ALL_SPEC

protected static final Integer ALL_SPEC

NO_SPEC

protected static final Integer NO_SPEC

monthMap

protected static final Map monthMap

dayMap

protected static final Map dayMap

seconds

protected transient TreeSet seconds

minutes

protected transient TreeSet minutes

hours

protected transient TreeSet hours

daysOfMonth

protected transient TreeSet daysOfMonth

months

protected transient TreeSet months

daysOfWeek

protected transient TreeSet daysOfWeek

years

protected transient TreeSet years

lastdayOfWeek

protected transient boolean lastdayOfWeek

nthdayOfWeek

protected transient int nthdayOfWeek

lastdayOfMonth

protected transient boolean lastdayOfMonth

nearestWeekday

protected transient boolean nearestWeekday

expressionParsed

protected transient boolean expressionParsed
Constructor Detail

CronExpression

public CronExpression(String cronExpression)               throws ParseException
Constructs a new CronExpression based on the specified parameter.

Parameters:
cronExpression - String representation of the cron expression the new object should represent
Throws:
ParseException - if the string expression cannot be parsed into a valid CronExpression

Method Detail

isSatisfiedBy

public boolean isSatisfiedBy(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 Date getNextValidTimeAfter(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 Date getNextInvalidTimeAfter(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

getTimeZone

public TimeZone getTimeZone()
Returns the time zone for which this CronExpression will be resolved.


setTimeZone

public void setTimeZone(TimeZone timeZone)
Sets the time zone for which this CronExpression will be resolved.


toString

public String toString()
Returns the string representation of the CronExpression

Overrides:
toString in class Object
Returns:
a string representation of the CronExpression

isValidExpression

public static boolean isValidExpression(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(String expression)                        throws ParseException
Throws:
ParseException

storeExpressionVals

protected int storeExpressionVals(int pos,                                  String s,                                  int type)                           throws ParseException
Throws:
ParseException

checkNext

protected int checkNext(int pos,                        String s,                        int val,                        int type)                 throws ParseException
Throws:
ParseException

getCronExpression

public String getCronExpression()

getExpressionSummary

public String getExpressionSummary()

getExpressionSetSummary

protected String getExpressionSetSummary(Set set)

getExpressionSetSummary

protected String getExpressionSetSummary(ArrayList list)

skipWhiteSpace

protected int skipWhiteSpace(int i,                             String s)

findNextWhiteSpace

protected int findNextWhiteSpace(int i,                                 String s)

addToSet

protected void addToSet(int val,                        int end,                        int incr,                        int type)                 throws ParseException
Throws:
ParseException

getSet

protected TreeSet getSet(int type)

getValue

protected org.quartz.ValueSet getValue(int v,                                       String s,                                       int i)

getNumericValue

protected int getNumericValue(String s,                              int i)

getMonthNumber

protected int getMonthNumber(String s)

getDayOfWeekNumber

protected int getDayOfWeekNumber(String s)

getTimeAfter

protected Date getTimeAfter(Date afterTime)

setCalendarHour

protected void setCalendarHour(Calendar cal,                               int hour)
Advance the calendar to the particular hour paying particular attention to daylight saving problems.

Parameters:
cal -
hour -

getTimeBefore

protected Date getTimeBefore(Date endTime)
NOT YET IMPLEMENTED: Returns the time before the given time that the CronExpression matches.


getFinalFireTime

public Date getFinalFireTime()
NOT YET IMPLEMENTED: Returns the final time that the CronExpression will match.


isLeapYear

protected boolean isLeapYear(int year)

getLastDayOfMonth

protected int getLastDayOfMonth(int monthNum,                                int year)

clone

public Object clone()
Overrides:
clone in class Object


Copyright 2001-2012,
Terracotta, Inc.


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