com.twitter.common.util
Class BackoffHelper

java.lang.Object
  com.twitter.common.util.BackoffHelper

public class BackoffHelper
extends Object

A utility for dealing with backoffs of retryable actions.

TODO(John Sirois): investigate synergies with BackoffDecider.

BackoffHelper

public BackoffHelper()

Creates a new BackoffHelper that uses truncated binary backoff starting at a 1 second backoff and maxing out at a 1 minute backoff.

BackoffHelper

public BackoffHelper(Amount<Long,Time> initialBackoff,
                     Amount<Long,Time> maxBackoff)

Creates a new BackoffHelper that uses truncated binary backoff starting at the given initialBackoff and maxing out at the given maxBackoff.

Parameters:

initialBackoff - the initial amount of time to back off

maxBackoff - the maximum amount of time to back off

BackoffHelper

public BackoffHelper(Amount<Long,Time> initialBackoff,
                     Amount<Long,Time> maxBackoff,
                     boolean stopAtMax)

Creates a new BackoffHelper that uses truncated binary backoff starting at the given initialBackoff and maxing out at the given maxBackoff. This will either:

• stopAtMax == true : throw BackoffExpiredException when maxBackoff is reached
• stopAtMax == false : continue backing off with maxBackoff

Parameters:

initialBackoff - the initial amount of time to back off

maxBackoff - the maximum amount of time to back off

stopAtMax - if true, this will throw BackoffStoppedException when the max backoff is reached

BackoffHelper

public BackoffHelper(BackoffStrategy backoffStrategy)

Creates a BackoffHelper that uses the given backoffStrategy to calculate backoffs between retries.

Parameters:

backoffStrategy - the backoff strategy to use

doUntilSuccess

public <E extends Exception> void doUntilSuccess(ExceptionalSupplier<Boolean,E> task)
                    throws InterruptedException,
                           BackoffHelper.BackoffStoppedException,
                           E extends Exception

Executes the given task using the configured backoff strategy until the task succeeds as indicated by returning true.

Parameters:

task - the retryable task to execute until success

Throws:

InterruptedException - if interrupted while waiting for the task to execute successfully

BackoffHelper.BackoffStoppedException - if the backoff stopped unsuccessfully

E - if the task throws

E extends Exception

doUntilResult

public <T,E extends Exception> T doUntilResult(ExceptionalSupplier<T,E> task)
                throws InterruptedException,
                       BackoffHelper.BackoffStoppedException,
                       E extends Exception

Executes the given task using the configured backoff strategy until the task succeeds as indicated by returning a non-null value.

Parameters:

task - the retryable task to execute until success

Returns:

the result of the successfully executed task

Throws:

InterruptedException - if interrupted while waiting for the task to execute successfully

BackoffHelper.BackoffStoppedException - if the backoff stopped unsuccessfully

E - if the task throws

E extends Exception