Package jakarta.ejb

Annotation Interface Schedule

@Target(METHOD)
@Retention(RUNTIME)
@Repeatable(Schedules.class)
public @interface Schedule

Schedule a timer for automatic creation with a timeout schedule based on a cron-like time expression. The annotated method is used as the timeout callback method.

All elements of this annotation are optional. If none are specified a persistent timer will be created with callbacks occuring every day at midnight in the default time zone associated with the container in which the application is executing.

There are seven elements that constitute a schedule specification which are listed below. In addition, the timezone element may be used to specify a non-default time zone in whose context the schedule specification is to be evaluated; the persistent element may be used to specify a non-persistent timer, and the info element may be used to specify additional information that may be retrieved when the timer callback occurs.

The elements that specify the calendar-based schedule itself are as follows:

• second : one or more seconds within a minute

  Allowable values: [0,59]

• minute : one or more minutes within an hour

  Allowable values : [0,59]

• hour : one or more hours within a day

  Allowable values : [0,23]

• dayOfMonth : one or more days within a month

  Allowable values:

  • [1,31]
  • [-7, -1]
  • "Last"
  • {"1st", "2nd", "3rd", "4th", "5th", "Last"} {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}

  "Last" means the last day of the month

  -x (where x is in the range [-7, -1]) means x day(s) before the last day of the month

  "1st","2nd", etc. applied to a day of the week identifies a single occurrence of that day within the month.

• month : one or more months within a year

  Allowable values :

  • [1,12]
  • {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", Dec"}
• dayOfWeek : one or more days within a week

  Allowable values :

  • [0,7]
  • {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}

  "0" and "7" both refer to Sunday

• year : a particular calendar year

  Allowable values : a four-digit calendar year

Each element supports values expressed in one of the following forms

• Single Value. This constrains the attribute to only one of its possible values.

  
   Example: second = "10"
   Example: month = "Sep"
   

• Wild Card. "*" represents all allowable values for a given attribute.

   Example: second = "*"
   Example: dayOfWeek = "*"
   

• List. This constrains the attribute to two or more allowable values or ranges, with a comma used as a separator character within the string. Each item in the list must be a single value or range. List items cannot be lists, wild cards, or increments. Duplicate values are ignored.

   Example: second = "10,20,30"
   Example: dayOfWeek = "Mon,Wed,Fri"
   Example: minute = "0-10,30,40"
   

• Range. This constrains the attribute to an inclusive range of values, with a dash separating both ends of the range. Each side of the range must be a single attribute value. Members of a range cannot be lists, wild cards, ranges, or increments. If x is larger than y in a range "x-y", the range is equivalent to "x-max, min-y", where max is the largest value of the corresponding attribute and min is the smallest. The range "x-x", where both range values are the same, evaluates to the single value x. The day of the week range "0-7" is equivalent to "*".

   Example: second = "1-10"
   Example: dayOfWeek = "Fri-Mon"
   Example: dayOfMonth = "27-3" (Equivalent to "27-Last , 1-3")
   

• Increments. The forward slash constrains an attribute based on a starting point and an interval, and is used to specify every N seconds, minutes, or hours within the minute, hour, or day, respectively. For the expression x/y, the attribute is constrained to every yth value within the set of allowable values beginning at time x. The x value is inclusive. The wild card character (*) can be used in the x position, and is equivalent to 0. The use of increments is only supported within the second, minute, and hour elements. For the second and minute elements, x and y must each be in the range [0,59]. For the hour element, x and y must each be in the range [0,23].

   Example: minute = "∗/5" (Every five minutes within the hour)
   

  This is equivalent to: minute = "0,5,10,15,20,25,30,35,40,45,50,55"

   Example: second = "30/10" (Every 10 seconds within the minute, starting at second 30)
   

  This is equivalent to: second = "30,40,50"

  Note that the set of matching increment values stops once the maximum value for that attribute is exceeded. It does not "roll over" past the boundary.

   Example : ( minute = "∗/14", hour="1,2")
   

  This is equivalent to: (minute = "0,14,28,42,56", hour = "1,2") (Every 14 minutes within the hour, for the hours of 1 and 2 a.m.)

The following additional rules apply to the schedule specification elements:

• If the dayOfMonth element has a non-wildcard value and the dayOfWeek element has a non-wildcard value, then any day matching either the dayOfMonth value or the dayOfWeek value will be considered to apply.
• Whitespace is ignored, except for string constants and numeric values.
• All string constants (e.g., "Sun", "Jan", "1st", etc.) are case insensitive.

Schedule-based timer times are evaluated in the context of the default time zone associated with the container in which the application is executing. A schedule-based timer may optionally override this default and associate itself with a specific time zone. If the schedule-based timer is associated with a specific time zone, all its times are evaluated in the context of that time zone, regardless of the default time zone in which the container is executing.

The timeout callback method to which the Schedule annotation is applied must have one of the following signatures, where <METHOD> designates the method name:

 void <METHOD>()
 void <METHOD>(Timer timer)
 

A timeout callback method can have public, private, protected, or package level access. A timeout callback method must not be declared as final or static. Timeout callback methods must not throw application exceptions.

Since:

EJB 3.1

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
String	dayOfMonth	Specifies one or more days within a month.
String	dayOfWeek	Specifies one or more days within a week.
String	hour	Specifies one or more hours within a day.
String	info	Specifies an information string that is associated with the timer
String	minute	Specifies one or more minutes with an hour.
String	month	Specifies one or more months within a year.
boolean	persistent	Specifies whether the timer that is created is persistent.
String	second	Specifies one or more seconds with in a minute.
String	timezone	Specifies the time zone within which the schedule is evaluated.
String	year	Specifies one or more years.

Element Details

second

String second

Specifies one or more seconds with in a minute.

Returns:

a String object.

Default:

"0"

minute

String minute

Specifies one or more minutes with an hour.

Returns:

a String object.

Default:

"0"

hour

String hour

Specifies one or more hours within a day.

Returns:

a String object.

Default:

"0"

dayOfMonth

String dayOfMonth

Specifies one or more days within a month.

Returns:

a String object.

Default:

"*"

month

String month

Specifies one or more months within a year.

Returns:

a String object.

Default:

"*"

dayOfWeek

String dayOfWeek

Specifies one or more days within a week.

Returns:

a String object.

Default:

"*"

year

String year

Specifies one or more years.

Returns:

a String object.

Default:

"*"

timezone

String timezone

Specifies the time zone within which the schedule is evaluated. Time zones are specified as an ID string. The set of required time zone IDs is defined by the Zone Name(TZ) column of the public domain zoneinfo database.

If a timezone is not specified, the schedule is evaluated in the context of the default timezone associated with the contianer in which the application is executing.

Returns:

a String object.

Default:

""

info

String info

Specifies an information string that is associated with the timer

Returns:

a String object.

Default:

""

persistent

boolean persistent

Specifies whether the timer that is created is persistent.

Returns:

a boolean.

Default:

true