org.apache.hadoop.io.retry
Class RetryPolicies

java.lang.Object
  org.apache.hadoop.io.retry.RetryPolicies

public class RetryPolicies
extends Object

A collection of useful implementations of RetryPolicy.

Field Summary

static RetryPolicy	RETRY_FOREVER Keep trying forever.
static RetryPolicy	TRY_ONCE_DONT_FAIL Try once, and fail silently for void methods, or by re-throwing the exception for non-void methods.
static RetryPolicy	TRY_ONCE_THEN_FAIL Try once, and fail by re-throwing the exception.

Constructor Summary

RetryPolicies()

Method Summary

static RetryPolicy	exponentialBackoffRetry(int maxRetries, long sleepTime, TimeUnit timeUnit) Keep trying a limited number of times, waiting a growing amount of time between attempts, and then fail by re-throwing the exception.
static RetryPolicy	retryByException(RetryPolicy defaultPolicy, Map<Class<? extends Exception>,RetryPolicy> exceptionToPolicyMap) Set a default policy with some explicit handlers for specific exceptions.
static RetryPolicy	retryByRemoteException(RetryPolicy defaultPolicy, Map<Class<? extends Exception>,RetryPolicy> exceptionToPolicyMap) A retry policy for RemoteException Set a default policy with some explicit handlers for specific exceptions.
static RetryPolicy	retryUpToMaximumCountWithFixedSleep(int maxRetries, long sleepTime, TimeUnit timeUnit) Keep trying a limited number of times, waiting a fixed time between attempts, and then fail by re-throwing the exception.
static RetryPolicy	retryUpToMaximumCountWithProportionalSleep(int maxRetries, long sleepTime, TimeUnit timeUnit) Keep trying a limited number of times, waiting a growing amount of time between attempts, and then fail by re-throwing the exception.
static RetryPolicy	retryUpToMaximumTimeWithFixedSleep(long maxTime, long sleepTime, TimeUnit timeUnit) Keep trying for a maximum time, waiting a fixed time between attempts, and then fail by re-throwing the exception.

Methods inherited from class java.lang.Object

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

Field Detail

TRY_ONCE_THEN_FAIL

public static final RetryPolicy TRY_ONCE_THEN_FAIL

Try once, and fail by re-throwing the exception. This corresponds to having no retry mechanism in place.

TRY_ONCE_DONT_FAIL

public static final RetryPolicy TRY_ONCE_DONT_FAIL

Try once, and fail silently for void methods, or by re-throwing the exception for non-void methods.

RETRY_FOREVER

public static final RetryPolicy RETRY_FOREVER

Keep trying forever.

Constructor Detail

RetryPolicies

public RetryPolicies()

Method Detail

retryUpToMaximumCountWithFixedSleep

public static final RetryPolicy retryUpToMaximumCountWithFixedSleep(int maxRetries,
                                                                    long sleepTime,
                                                                    TimeUnit timeUnit)

Keep trying a limited number of times, waiting a fixed time between attempts, and then fail by re-throwing the exception.

retryUpToMaximumTimeWithFixedSleep

public static final RetryPolicy retryUpToMaximumTimeWithFixedSleep(long maxTime,
                                                                   long sleepTime,
                                                                   TimeUnit timeUnit)

Keep trying for a maximum time, waiting a fixed time between attempts, and then fail by re-throwing the exception.

retryUpToMaximumCountWithProportionalSleep

public static final RetryPolicy retryUpToMaximumCountWithProportionalSleep(int maxRetries,
                                                                           long sleepTime,
                                                                           TimeUnit timeUnit)

Keep trying a limited number of times, waiting a growing amount of time between attempts, and then fail by re-throwing the exception. The time between attempts is sleepTime mutliplied by the number of tries so far.

exponentialBackoffRetry

public static final RetryPolicy exponentialBackoffRetry(int maxRetries,
                                                        long sleepTime,
                                                        TimeUnit timeUnit)

Keep trying a limited number of times, waiting a growing amount of time between attempts, and then fail by re-throwing the exception. The time between attempts is sleepTime mutliplied by a random number in the range of [0, 2 to the number of retries)

retryByException

public static final RetryPolicy retryByException(RetryPolicy defaultPolicy,
                                                 Map<Class<? extends Exception>,RetryPolicy> exceptionToPolicyMap)

Set a default policy with some explicit handlers for specific exceptions.

retryByRemoteException

public static final RetryPolicy retryByRemoteException(RetryPolicy defaultPolicy,
                                                       Map<Class<? extends Exception>,RetryPolicy> exceptionToPolicyMap)

A retry policy for RemoteException Set a default policy with some explicit handlers for specific exceptions.