Package org.springframework.scheduling.support

Class CronTrigger

java.lang.Object
org.springframework.scheduling.support.CronTrigger
All Implemented Interfaces:
Trigger
public class CronTrigger extends Object implements Trigger
Trigger implementation for cron expressions. Wraps a CronExpression.
Since:
3.0
Author:
Juergen Hoeller, Arjen Poutsma
See Also:

  • Constructor Details

    • CronTrigger

      public CronTrigger(String expression)
      Build a CronTrigger from the pattern provided in the default time zone.

      This is equivalent to the forLenientExecution(java.lang.String) factory method. Original trigger firings may be skipped if the previous task is still running; if this is not desirable, consider forFixedExecution(java.lang.String).

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      See Also:

    • CronTrigger

      public CronTrigger(String expression, TimeZone timeZone)
      Build a CronTrigger from the pattern provided in the given time zone, with the same lenient execution as CronTrigger(String).

      Note that such explicit time zone customization is usually not necessary, using TaskScheduler.getClock() instead.

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      timeZone - a time zone in which the trigger times will be generated

    • CronTrigger

      public CronTrigger(String expression, ZoneId zoneId)
      Build a CronTrigger from the pattern provided in the given time zone, with the same lenient execution as CronTrigger(String).

      Note that such explicit time zone customization is usually not necessary, using TaskScheduler.getClock() instead.

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      zoneId - a time zone in which the trigger times will be generated
      Since:
      5.3
      See Also:

  • Method Details

    • getExpression

      public String getExpression()
      Return the cron pattern that this trigger has been built with.

    • nextExecution

      public Instant nextExecution(TriggerContext triggerContext)
      Determine the next execution time according to the given trigger context.

      Next execution times are calculated based on the completion time of the previous execution; therefore, overlapping executions won't occur.

      Specified by:
      nextExecution in interface Trigger
      Parameters:
      triggerContext - context object encapsulating last execution times and last completion time
      Returns:
      the next execution time as defined by the trigger, or null if the trigger won't fire anymore

    • equals

      public boolean equals(@Nullable Object other)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • forLenientExecution

      public static CronTrigger forLenientExecution(String expression)
      Create a CronTrigger for lenient execution, to be rescheduled after every task based on the completion time.

      This variant does not make up for missed trigger firings if the associated task has taken too long. As a consequence, original trigger firings may be skipped if the previous task is still running.

      This is equivalent to the regular CronTrigger constructor. Note that lenient execution is scheduler-dependent: it may skip trigger firings with long-running tasks on a thread pool while executing at forFixedExecution(java.lang.String)-like precision with new threads per task.

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      Since:
      6.1.3
      See Also:

    • resumeLenientExecution

      public static CronTrigger resumeLenientExecution(String expression, Instant resumptionTimestamp)
      Create a CronTrigger for lenient execution, to be rescheduled after every task based on the completion time.

      This variant does not make up for missed trigger firings if the associated task has taken too long. As a consequence, original trigger firings may be skipped if the previous task is still running.

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      resumptionTimestamp - the timestamp to resume from (the last-known completion timestamp), with the new trigger calculated from there and possibly immediately firing (but only once, every subsequent calculation will start from the completion time of that first resumed trigger)
      Since:
      6.1.3
      See Also:

    • forFixedExecution

      public static CronTrigger forFixedExecution(String expression)
      Create a CronTrigger for fixed execution, to be rescheduled after every task based on the last scheduled time.

      This variant makes up for missed trigger firings if the associated task has taken too long, scheduling a task for every original trigger firing. Such follow-up tasks may execute late but will never be skipped.

      Immediate versus late execution in case of long-running tasks may be scheduler-dependent but the guarantee to never skip a task is portable.

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      Since:
      6.1.3
      See Also:

    • resumeFixedExecution

      public static CronTrigger resumeFixedExecution(String expression, Instant resumptionTimestamp)
      Create a CronTrigger for fixed execution, to be rescheduled after every task based on the last scheduled time.

      This variant makes up for missed trigger firings if the associated task has taken too long, scheduling a task for every original trigger firing. Such follow-up tasks may execute late but will never be skipped.

      Parameters:
      expression - a space-separated list of time fields, following cron expression conventions
      resumptionTimestamp - the timestamp to resume from (the last-known scheduled timestamp), with every trigger in-between immediately firing to make up for every execution that would have happened in the meantime
      Since:
      6.1.3
      See Also: