com.sun.sgs.kernel.schedule
Interface SchedulerRetryPolicy

All Known Implementing Classes:

ImmediateRetryPolicy, NowOrLaterRetryPolicy

public interface SchedulerRetryPolicy

This interface is used to define a retry policy for a scheduler when a transactional task fails.

All implementations must implement a constructor of the form (java.util.Properties).

Method Summary

SchedulerRetryAction

getRetryAction(ScheduledTask task) Determines if and how a task should be retried after a failure.

Method Detail

getRetryAction

SchedulerRetryAction getRetryAction(ScheduledTask task)

Determines if and how a task should be retried after a failure. This method should be called by a scheduler if a task aborts.

• A return value of SchedulerRetryAction.DROP means that the task should be dropped and not retried.
• A return value of SchedulerRetryAction.RETRY_LATER means that the task should be retried by the scheduler at some point in the future.
• A return value of SchedulerRetryAction.RETRY_NOW means that the task should be retried immediately.

This method may modify the given task in order to affect how the scheduler behaves when re-executing.

Note: The Throwable cause of the most recent failure of the given task should always be accessible via the ScheduledTask.getLastFailure() method. This Throwable may implement ExceptionRetryStatus. If it does, care should be taken to abide by the contract specified by the TaskManager with regard to Throwables that implement this interface.

Note: The proper way to drop a task with a custom policy is to return DROP with this method. Implementations should not use a call to cancel on the given task.

Parameters:

task - the task that has been aborted

Returns:

the SchedulerRetryAction that the scheduler should take with respect to retrying the given task

Throws:

IllegalArgumentException - if task is null

IllegalStateException - if the given task's most recent failure is null