io.pravega.common.util

Class Retry

java.lang.Object

io.pravega.common.util.Retry

public final class Retry
extends java.lang.Object

A Utility class to support retrying something that can fail with exponential backoff. The class is designed to have a declarative interface for ease of use. It can be used as follows:

Retry.withExpBackoff(1, 10, 5) .retryingOn(FooException.class) .throwingOn(RuntimeException.class).run(() -> { //Do stuff here. }

The above will retry the code in the block up to 5 times if it throws FooException. If it throws a RuntimeException or returns successfully it will throw or return immediately. The delay following each of the filed attempts would be 1, 10, 100, 1000, and 10000ms respectively. If all retries fail RetriesExhaustedException will be thrown.

Note that the class is not a builder object, so the methods in the chain must be invoked in order. The intermediate objects in the chain are reusable and threadsafe, so they can be shared between invocations.

In the event that the exception passed to retryingOn() and throwingOn() are related. i.e. In the above example if FooException were to extend RuntimeException. Then the more specific exception is given preference. (In the above case FooException would be retried).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Retry.Retryable<ReturnT,RetryableET extends java.lang.Exception,NonRetryableET extends java.lang.Exception>
static class	Retry.RetryAndThrowBase<ThrowsT extends java.lang.Exception>
static class	Retry.RetryAndThrowConditionally Returned by Retry.RetryExceptionally.throwingOn(Class) to add the type of exception that should cause the method to throw right away.
static class	Retry.RetryAndThrowExceptionally<RetryT extends java.lang.Exception,ThrowsT extends java.lang.Exception> Returned by Retry.RetryExceptionally.throwingOn(Class) to add the type of exception that should cause the method to throw right away.
static class	Retry.RetryExceptionally<RetryT extends java.lang.Exception> Returned by Retry.RetryWithBackoff.retryingOn(Class) to add the type of exception that should result in a retry.
static class	Retry.RetryUnconditionally Returned by indefinitelyWithExpBackoff(long, int, long, Consumer) (Class)} to retry indefinitely.
static class	Retry.RetryWithBackoff Returned by withExpBackoff(long, int, int) to set the retry schedule.

Method Summary

Modifier and Type	Method and Description
static Retry.RetryUnconditionally	indefinitelyWithExpBackoff(long initialMillis, int multiplier, long maxDelay, java.util.function.Consumer<java.lang.Throwable> consumer)
static Retry.RetryUnconditionally	indefinitelyWithExpBackoff(java.lang.String failureMessage)
static Retry.RetryWithBackoff	withExpBackoff(long initialMillis, int multiplier, int attempts)
static Retry.RetryWithBackoff	withExpBackoff(long initialMillis, int multiplier, int attempts, long maxDelay)

Methods inherited from class java.lang.Object

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

Method Detail

withExpBackoff

public static Retry.RetryWithBackoff withExpBackoff(long initialMillis,
                                                    int multiplier,
                                                    int attempts)

withExpBackoff

public static Retry.RetryWithBackoff withExpBackoff(long initialMillis,
                                                    int multiplier,
                                                    int attempts,
                                                    long maxDelay)

indefinitelyWithExpBackoff

public static Retry.RetryUnconditionally indefinitelyWithExpBackoff(long initialMillis,
                                                                    int multiplier,
                                                                    long maxDelay,
                                                                    java.util.function.Consumer<java.lang.Throwable> consumer)

indefinitelyWithExpBackoff

public static Retry.RetryUnconditionally indefinitelyWithExpBackoff(java.lang.String failureMessage)