Package org.camunda.bpm.client.backoff

Interface ErrorAwareBackoffStrategy

All Superinterfaces:

BackoffStrategy

All Known Implementing Classes:

ExponentialErrorBackoffStrategy

public interface ErrorAwareBackoffStrategy
extends BackoffStrategy

Provides a way to define a back off between fetch and lock requests.

Note: Since an implementation of this interface may be executed by multiple threads, it is recommended to implement the custom backoff strategy in a thread-safe manner.

Method Summary

Modifier and Type	Method	Description
long	calculateBackoffTime()	Calculates the back off time and is invoked after reconfigure(List, ExternalTaskClientException).
default void	reconfigure(List<ExternalTask> externalTasks)	This is to provide compatibility with existing BackoffStrategy configurations.
void	reconfigure(List<ExternalTask> externalTasks, ExternalTaskClientException exception)	Reconfigures the back off strategy based on the fetched external tasks and any error that might have occurred.

Method Details

reconfigure

default void reconfigure(List<ExternalTask> externalTasks)

This is to provide compatibility with existing BackoffStrategy configurations. Do not override. Implementations of ErrorAwareBackoffStrategy should override reconfigure(List, ExternalTaskClientException) instead.

Specified by:

reconfigure in interface BackoffStrategy

Parameters:

externalTasks - which have been fetched

reconfigure

void reconfigure(List<ExternalTask> externalTasks,
 ExternalTaskClientException exception)

Reconfigures the back off strategy based on the fetched external tasks and any error that might have occurred. It is invoked before calculateBackoffTime().

The implementation might count the amount of invocations and realize a strategy reset.

Parameters:

externalTasks - which have been fetched

exception - can be of the following types:

• EngineException if something went wrong during the engine execution (e.g., a persistence exception occurred).
• BadRequestException if an illegal operation was performed or the given data is invalid.
• ConnectionLostException if the connection could not be established.
• UnknownHttpErrorException if the HTTP status code is not known by the client.

calculateBackoffTime

long calculateBackoffTime()

Calculates the back off time and is invoked after reconfigure(List, ExternalTaskClientException).

Specified by:

calculateBackoffTime in interface BackoffStrategy

Returns:

the back off time between fetch and lock requests in milliseconds