org.apache.lens.server.api.common

Interface BackOffRetryHandler

All Known Implementing Classes:

FibonacciExponentialBackOffRetryHandler

public interface BackOffRetryHandler

A backoff retry handler. This allows a backoff on any call, so provides methods whether we can try the operation now, whats next time when operation can be performed and whether operation has exhausted all retries. Callers of this would do the following : if (handler.canTryOpNow(FailureContext)) { try { tryCallerOperation(); FailureContext.clear(); } catch (any Transient Exception) { FailureContext.updateFailure(); if (!handler.hasExhaustedRetries(FailureContext)) { // will be tried later again } throw exception; } }

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canTryOpNow(FailureContext failContext) To know whether operation can be done now.
long	getOperationNextTime(FailureContext failContext) Get the time when the operation can be done next.
boolean	hasExhaustedRetries(FailureContext failContext) Has the operation exhausted all its retries

Method Detail

canTryOpNow

boolean canTryOpNow(FailureContext failContext)

To know whether operation can be done now.

Parameters:

failContext - FailureContext holding failures till now.

Returns:

true if operation can be done now, false otherwise.

getOperationNextTime

long getOperationNextTime(FailureContext failContext)

Get the time when the operation can be done next.

Parameters:

failContext - FailureContext holding failures till now.

Returns:

Next operation time in millis since epoch

hasExhaustedRetries

boolean hasExhaustedRetries(FailureContext failContext)

Has the operation exhausted all its retries

Parameters:

failContext - FailureContext holding failures till now.

Returns:

true if all retries have exhausted, false otherwise.