Class KieCronExpression
- java.lang.Object
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- org.drools.core.time.impl.KieCronExpression
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- All Implemented Interfaces:
java.io.Serializable
- Direct Known Subclasses:
CronExpression
public class KieCronExpression extends java.lang.Object implements java.io.Serializable
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".
- See Also:
- Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
KieCronExpression.ValueSet
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Field Summary
Fields Modifier and Type Field Description protected static java.lang.Integer
ALL_SPEC
protected static int
ALL_SPEC_INT
protected java.lang.String
cronExpression
protected static int
DAY_OF_MONTH
protected static int
DAY_OF_WEEK
protected static java.util.Map<java.lang.String,java.lang.Integer>
dayMap
protected java.util.TreeSet
daysOfMonth
protected java.util.TreeSet
daysOfWeek
protected boolean
expressionParsed
protected static int
HOUR
protected java.util.TreeSet
hours
protected boolean
lastdayOfMonth
protected boolean
lastdayOfWeek
protected static int
MINUTE
protected java.util.TreeSet
minutes
protected static int
MONTH
protected static java.util.Map<java.lang.String,java.lang.Integer>
monthMap
protected java.util.TreeSet
months
protected boolean
nearestWeekday
protected static java.lang.Integer
NO_SPEC
protected static int
NO_SPEC_INT
protected int
nthdayOfWeek
protected static int
SECOND
protected java.util.TreeSet
seconds
protected static int
YEAR
protected static int
YEAR_TO_GIVEUP_SCHEDULING_AT
protected java.util.TreeSet
years
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Constructor Summary
Constructors Constructor Description KieCronExpression(java.lang.String cronExpression)
Constructs a newCronExpression
based on the specified parameter.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
addToSet(int val, int end, int incr, int type)
protected void
buildExpression(java.lang.String expression)
protected int
checkNext(int pos, java.lang.String s, int val, int type)
protected int
findNextWhiteSpace(int i, java.lang.String s)
java.lang.String
getCronExpression()
protected int
getDayOfWeekNumber(java.lang.String s)
protected java.lang.String
getExpressionSetSummary(java.util.ArrayList list)
protected java.lang.String
getExpressionSetSummary(java.util.Set set)
java.lang.String
getExpressionSummary()
protected int
getMonthNumber(java.lang.String s)
protected int
getNumericValue(java.lang.String s, int i)
protected java.util.TreeSet
getSet(int type)
protected KieCronExpression.ValueSet
getValue(int v, java.lang.String s, int i)
static boolean
isValidExpression(java.lang.String cronExpression)
Indicates whether the specified cron expression can be parsed into a valid cron expressionprotected 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 theCronExpression
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Field Detail
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YEAR_TO_GIVEUP_SCHEDULING_AT
protected static final int YEAR_TO_GIVEUP_SCHEDULING_AT
- See Also:
- Constant Field Values
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SECOND
protected static final int SECOND
- See Also:
- Constant Field Values
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MINUTE
protected static final int MINUTE
- See Also:
- Constant Field Values
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HOUR
protected static final int HOUR
- See Also:
- Constant Field Values
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DAY_OF_MONTH
protected static final int DAY_OF_MONTH
- See Also:
- Constant Field Values
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MONTH
protected static final int MONTH
- See Also:
- Constant Field Values
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DAY_OF_WEEK
protected static final int DAY_OF_WEEK
- See Also:
- Constant Field Values
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YEAR
protected static final int YEAR
- See Also:
- Constant Field Values
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ALL_SPEC_INT
protected static final int ALL_SPEC_INT
- See Also:
- Constant Field Values
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NO_SPEC_INT
protected static final int NO_SPEC_INT
- See Also:
- Constant Field Values
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ALL_SPEC
protected static final java.lang.Integer ALL_SPEC
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NO_SPEC
protected static final java.lang.Integer NO_SPEC
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monthMap
protected static final java.util.Map<java.lang.String,java.lang.Integer> monthMap
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dayMap
protected static final java.util.Map<java.lang.String,java.lang.Integer> dayMap
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cronExpression
protected java.lang.String cronExpression
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seconds
protected transient java.util.TreeSet seconds
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minutes
protected transient java.util.TreeSet minutes
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hours
protected transient java.util.TreeSet hours
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daysOfMonth
protected transient java.util.TreeSet daysOfMonth
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months
protected transient java.util.TreeSet months
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daysOfWeek
protected transient java.util.TreeSet daysOfWeek
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years
protected transient java.util.TreeSet years
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lastdayOfWeek
protected transient boolean lastdayOfWeek
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nthdayOfWeek
protected transient int nthdayOfWeek
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lastdayOfMonth
protected transient boolean lastdayOfMonth
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nearestWeekday
protected transient boolean nearestWeekday
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expressionParsed
protected transient boolean expressionParsed
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Constructor Detail
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KieCronExpression
public KieCronExpression(java.lang.String cronExpression) throws java.text.ParseException
Constructs a newCronExpression
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 validCronExpression
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Method Detail
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toString
public java.lang.String toString()
Returns the string representation of theCronExpression
- Overrides:
toString
in classjava.lang.Object
- Returns:
- a string representation of the
CronExpression
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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
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buildExpression
protected void buildExpression(java.lang.String expression) throws java.text.ParseException
- Throws:
java.text.ParseException
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storeExpressionVals
protected int storeExpressionVals(int pos, java.lang.String s, int type) throws java.text.ParseException
- Throws:
java.text.ParseException
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checkNext
protected int checkNext(int pos, java.lang.String s, int val, int type) throws java.text.ParseException
- Throws:
java.text.ParseException
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getCronExpression
public java.lang.String getCronExpression()
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getExpressionSummary
public java.lang.String getExpressionSummary()
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getExpressionSetSummary
protected java.lang.String getExpressionSetSummary(java.util.Set set)
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getExpressionSetSummary
protected java.lang.String getExpressionSetSummary(java.util.ArrayList list)
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skipWhiteSpace
protected int skipWhiteSpace(int i, java.lang.String s)
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findNextWhiteSpace
protected int findNextWhiteSpace(int i, java.lang.String s)
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addToSet
protected void addToSet(int val, int end, int incr, int type) throws java.text.ParseException
- Throws:
java.text.ParseException
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getSet
protected java.util.TreeSet getSet(int type)
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getValue
protected KieCronExpression.ValueSet getValue(int v, java.lang.String s, int i)
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getNumericValue
protected int getNumericValue(java.lang.String s, int i)
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getMonthNumber
protected int getMonthNumber(java.lang.String s)
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getDayOfWeekNumber
protected int getDayOfWeekNumber(java.lang.String s)
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