org.springframework.retry.backoff

Class ExponentialRandomBackOffPolicy

java.lang.Object

org.springframework.retry.backoff.ExponentialBackOffPolicy

org.springframework.retry.backoff.ExponentialRandomBackOffPolicy

All Implemented Interfaces:

BackOffPolicy, SleepingBackOffPolicy<ExponentialBackOffPolicy>

public class ExponentialRandomBackOffPolicy
extends ExponentialBackOffPolicy

Implementation of ExponentialBackOffPolicy that chooses a random multiple of the interval that would come from a simple deterministic exponential. The random multiple is uniformly distributed between 1 and the deterministic multiplier (so in practice the interval is somewhere between the next and next but one intervals in the deterministic case). This has shown to at least be useful in testing scenarios where excessive contention is generated by the test needing many retries. In test, usually threads are started at the same time, and thus stomp together onto the next interval. Using this BackOffPolicy can help avoid that scenario. Example: initialInterval = 50 multiplier = 2.0 maxInterval = 3000 numRetries = 5 ExponentialBackOffPolicy yields: [50, 100, 200, 400, 800] ExponentialRandomBackOffPolicy may yield [76, 151, 304, 580, 901] or [53, 190, 267, 451, 815]

Author:

Jon Travis, Dave Syer

Field Summary

Fields inherited from class org.springframework.retry.backoff.ExponentialBackOffPolicy

DEFAULT_INITIAL_INTERVAL, DEFAULT_MAX_INTERVAL, DEFAULT_MULTIPLIER, logger

Constructor Summary

Constructors

Constructor and Description
ExponentialRandomBackOffPolicy()

Method Summary

Modifier and Type	Method and Description
protected ExponentialBackOffPolicy	newInstance()
BackOffContext	start(RetryContext context) Returns a new instance of BackOffContext, seeded with this policies settings.

Methods inherited from class org.springframework.retry.backoff.ExponentialBackOffPolicy

backOff, cloneValues, getInitialInterval, getMaxInterval, getMultiplier, setInitialInterval, setMaxInterval, setMultiplier, setSleeper, toString, withSleeper

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ExponentialRandomBackOffPolicy

public ExponentialRandomBackOffPolicy()

Method Detail

start

public BackOffContext start(RetryContext context)

Returns a new instance of BackOffContext, seeded with this policies settings.

Specified by:

start in interface BackOffPolicy

Overrides:

start in class ExponentialBackOffPolicy

Parameters:

context - the RetryContext context, which might contain information that we can use to decide how to proceed.

Returns:

the implementation-specific BackOffContext or 'null'.

newInstance

protected ExponentialBackOffPolicy newInstance()

Overrides:

newInstance in class ExponentialBackOffPolicy