org.jclouds.http.handlers
Class BackoffLimitedRetryHandler

java.lang.Object
  org.jclouds.http.handlers.BackoffLimitedRetryHandler

All Implemented Interfaces:

HttpRetryHandler, IOExceptionRetryHandler

Direct Known Subclasses:

InvalidateSessionAndRetryOn401AndLogoutOnClose

@Singleton
public class BackoffLimitedRetryHandler
extends Object
implements HttpRetryHandler, IOExceptionRetryHandler

Allow replayable request to be retried a limited number of times, and impose an exponential back-off delay before returning.

The back-off delay grows rapidly according to the formula 50 * (HttpCommand.getFailureCount() ^ 2). For example:

Number of Attempts	Delay in milliseconds
1	50
2	200
3	450
4	800
5	1250

This implementation has two side-effects. It increments the command's failure count with HttpCommand.incrementFailureCount(), because this failure count value is used to determine how many times the command has already been tried. It also closes the response's content input stream to ensure connections are cleaned up.

Author:

James Murty

Field Summary

static BackoffLimitedRetryHandler	INSTANCE
protected Logger	logger

Fields inherited from interface org.jclouds.http.HttpRetryHandler

ALWAYS_RETRY, NEVER_RETRY

Fields inherited from interface org.jclouds.http.IOExceptionRetryHandler

ALWAYS_RETRY, NEVER_RETRY

Constructor Summary

BackoffLimitedRetryHandler()

Method Summary

void	imposeBackoffExponentialDelay(int failureCount, String commandDescription)
void	imposeBackoffExponentialDelay(long period, int pow, int failureCount, int max, String commandDescription)
void	imposeBackoffExponentialDelay(long period, long maxPeriod, int pow, int failureCount, int max, String commandDescription)
boolean	shouldRetryRequest(HttpCommand command, HttpResponse response) Return true if the command should be retried.
boolean	shouldRetryRequest(HttpCommand command, IOException error)

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static BackoffLimitedRetryHandler INSTANCE

logger

protected Logger logger

Constructor Detail

BackoffLimitedRetryHandler

public BackoffLimitedRetryHandler()

Method Detail

shouldRetryRequest

public boolean shouldRetryRequest(HttpCommand command,
                                  IOException error)

Specified by:

shouldRetryRequest in interface IOExceptionRetryHandler

shouldRetryRequest

public boolean shouldRetryRequest(HttpCommand command,
                                  HttpResponse response)

Description copied from interface: HttpRetryHandler

Return true if the command should be retried. This method should only be invoked when the response has failed with a HTTP 5xx error indicating a server-side error.

Specified by:

shouldRetryRequest in interface HttpRetryHandler

imposeBackoffExponentialDelay

public void imposeBackoffExponentialDelay(int failureCount,
                                          String commandDescription)

imposeBackoffExponentialDelay

public void imposeBackoffExponentialDelay(long period,
                                          int pow,
                                          int failureCount,
                                          int max,
                                          String commandDescription)

imposeBackoffExponentialDelay

public void imposeBackoffExponentialDelay(long period,
                                          long maxPeriod,
                                          int pow,
                                          int failureCount,
                                          int max,
                                          String commandDescription)