@LimitedPrivate({"HBase","HDFS","MapReduce"}) @Evolving

Package org.apache.hadoop.io.retry

A mechanism for selectively retrying methods that throw exceptions under certain circumstances. Typical usage is UnreliableImplementation unreliableImpl = new UnreliableImplementation(); UnreliableInterface unreliable = (UnreliableInterface) RetryProxy.create(UnreliableInterface.class, unreliableImpl, RetryPolicies.retryUpToMaximumCountWithFixedSleep(4, 10, TimeUnit.SECONDS)); unreliable.call(); This will retry any method called on unreliable four times - in this case the call() method - sleeping 10 seconds between each retry. There are a number of retry policies available, or you can implement a custom one by implementing RetryPolicy. It is also possible to specify retry policies on a per-method basis.

Interface Summary

Interface	Description
FailoverProxyProvider<T>	An implementer of this interface is capable of providing proxy objects for use in IPC communication, and potentially modifying these objects or creating entirely new ones in the event of certain types of failures.
RetryPolicy	Specifies a policy for retrying method failures.

Class Summary

Class	Description
AsyncCallHandler	Handle async calls.
DefaultFailoverProxyProvider<T>	An implementation of FailoverProxyProvider which does nothing in the event of failover, and always returns the same proxy object.
FailoverProxyProvider.ProxyInfo<T>
LossyRetryInvocationHandler<T>	A dummy invocation handler extending RetryInvocationHandler.
RetryInvocationHandler<T>	A RpcInvocationHandler which supports client side retry .
RetryPolicies	A collection of useful implementations of RetryPolicy.
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.
RetryPolicies.MultipleLinearRandomRetry.Pair	Pairs of numRetries and sleepSeconds
RetryPolicy.RetryAction	Returned by RetryPolicy.shouldRetry(Exception, int, int, boolean).
RetryProxy	A factory for creating retry proxies.
RetryUtils

Enum Summary

Enum	Description
RetryPolicy.RetryAction.RetryDecision

Exception Summary

Exception	Description
MultiException	Holder class that clients can use to return multiple exceptions.

Annotation Types Summary

Annotation Type	Description
AtMostOnce	Used to mark certain methods of an interface with at-most-once semantics.
Idempotent	Used to mark certain methods of an interface as being idempotent, and therefore warrant being retried on failover.