Package com.azure.core.http.policy

Class ExponentialBackoff

java.lang.Object

com.azure.core.http.policy.ExponentialBackoff

All Implemented Interfaces:

RetryStrategy

public class ExponentialBackoff
extends Object
implements RetryStrategy

The ExponentialBackoff class is an implementation of the RetryStrategy interface. This strategy uses a delay duration that exponentially increases with each retry attempt until an upper bound is reached, after which every retry attempt is delayed by the provided max delay duration.

This class is useful when you need to handle retries for operations that may transiently fail. It ensures that the retries are performed with an increasing delay to avoid overloading the system.

Code sample:

In this example, an ExponentialBackoff is created and used in a RetryPolicy which can be added to a pipeline. For a request sent by the pipeline, if the server responds with a transient error, the request will be retried with an exponentially increasing delay.

 ExponentialBackoff retryStrategy = new ExponentialBackoff();
 RetryPolicy policy = new RetryPolicy(retryStrategy);
 

See Also:

• com.azure.core.http.policy
• RetryStrategy
• RetryPolicy
• HttpPipeline
• HttpRequest
• HttpResponse

Field Summary

Fields inherited from interface com.azure.core.http.policy.RetryStrategy

HTTP_STATUS_TOO_MANY_REQUESTS

Constructor Summary

Constructors

Constructor	Description
ExponentialBackoff()	Creates an instance of ExponentialBackoff with a maximum number of retry attempts configured by the environment property Configuration.PROPERTY_AZURE_REQUEST_RETRY_COUNT, or three if it isn't configured or is less than or equal to 0.
ExponentialBackoff(int maxRetries, Duration baseDelay, Duration maxDelay)	Creates an instance of ExponentialBackoff.
ExponentialBackoff(ExponentialBackoffOptions options)	Creates an instance of ExponentialBackoff.

Method Summary

Modifier and Type	Method	Description
Duration	calculateRetryDelay(int retryAttempts)	Computes the delay between each retry.
int	getMaxRetries()	Max number of retry attempts to be made.
boolean	shouldRetryCondition(RequestRetryCondition requestRetryCondition)	This method is consulted to determine if a retry attempt should be made for the given RequestRetryCondition.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.azure.core.http.policy.RetryStrategy

calculateRetryDelay, shouldRetry, shouldRetryException

Constructor Details

ExponentialBackoff

public ExponentialBackoff()

Creates an instance of ExponentialBackoff with a maximum number of retry attempts configured by the environment property Configuration.PROPERTY_AZURE_REQUEST_RETRY_COUNT, or three if it isn't configured or is less than or equal to 0. This strategy starts with a delay of 800 milliseconds and exponentially increases with each additional retry attempt to a maximum of 8 seconds.

ExponentialBackoff

public ExponentialBackoff(ExponentialBackoffOptions options)

Creates an instance of ExponentialBackoff.

Parameters:

options - The ExponentialBackoffOptions.

Throws:

NullPointerException - if options is null.

ExponentialBackoff

public ExponentialBackoff(int maxRetries,
 Duration baseDelay,
 Duration maxDelay)

Creates an instance of ExponentialBackoff.

Parameters:

maxRetries - The max retry attempts that can be made.

baseDelay - The base delay duration for retry.

maxDelay - The max delay duration for retry.

Throws:

IllegalArgumentException - if maxRetries is less than 0 or baseDelay is less than or equal to 0 or maxDelay is less than baseDelay.

Method Details

getMaxRetries

public int getMaxRetries()

Description copied from interface: RetryStrategy

Max number of retry attempts to be made.

Specified by:

getMaxRetries in interface RetryStrategy

Returns:

The max number of retry attempts.

calculateRetryDelay

public Duration calculateRetryDelay(int retryAttempts)

Description copied from interface: RetryStrategy

Computes the delay between each retry.

If both this method and RetryStrategy.calculateRetryDelay(RequestRetryCondition) are overridden, this method is ignored.

Specified by:

calculateRetryDelay in interface RetryStrategy

Parameters:

retryAttempts - The number of retry attempts completed so far.

Returns:

The delay duration before the next retry.

shouldRetryCondition

public boolean shouldRetryCondition(RequestRetryCondition requestRetryCondition)

Description copied from interface: RetryStrategy

This method is consulted to determine if a retry attempt should be made for the given RequestRetryCondition.

By default, if the RequestRetryCondition contains a non-null HttpResponse, then the RetryStrategy.shouldRetry(HttpResponse) method is called, otherwise the RetryStrategy.shouldRetryException(Throwable) method is called.

Specified by:

shouldRetryCondition in interface RetryStrategy

Parameters:

requestRetryCondition - The RequestRetryCondition containing information that can be used to determine if the request should be retried.

Returns:

Whether a retry should be attempted.