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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RetryPolicies.MultipleLinearRandomRetry Given pairs of number of retries and sleep time (n0, t0), (n1, t1), ..., the first n0 retries sleep t0 milliseconds on average, the following n1 retries sleep t1 milliseconds on average, and so on.

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.commons.logging.Log	LOG
static RetryPolicy	RETRY_FOREVER Keep trying forever.
static RetryPolicy	TRY_ONCE_THEN_FAIL Try once, and fail by re-throwing the exception.

Constructor Summary

Constructors

Constructor and Description
RetryPolicies()

Method Summary

Methods

Modifier and Type	Method and Description
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	failoverOnNetworkException(int maxFailovers)
static RetryPolicy	failoverOnNetworkException(RetryPolicy fallbackPolicy, int maxFailovers)
static RetryPolicy	failoverOnNetworkException(RetryPolicy fallbackPolicy, int maxFailovers, long delayMillis, long maxDelayBase)
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

LOG

public static final org.apache.commons.logging.Log LOG

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.

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.

failoverOnNetworkException

public static final RetryPolicy failoverOnNetworkException(int maxFailovers)

failoverOnNetworkException

public static final RetryPolicy failoverOnNetworkException(RetryPolicy fallbackPolicy,
                                     int maxFailovers)

failoverOnNetworkException

public static final RetryPolicy failoverOnNetworkException(RetryPolicy fallbackPolicy,
                                     int maxFailovers,
                                     long delayMillis,
                                     long maxDelayBase)