RetrySpec (reactor-core 3.4.0-SNAPSHOT)

java.lang.Object
- reactor.util.retry.Retry
- - reactor.util.retry.RetrySpec

```
public final class RetrySpec
extends Retry
```
A simple count-based Retry strategy with configurable features. Use Retry.max(long), Retry.maxInARow(long) or Retry.indefinitely() to obtain a preconfigured instance to start with.
Only errors that match the filter(Predicate) are retried (by default all), up to maxAttempts(long) times.
When the maximum attempt of retries is reached, a runtime exception is propagated downstream which can be pinpointed with Exceptions.isRetryExhausted(Throwable). The cause of the last attempt's failure is attached as said retryExhausted exception's cause. This can be customized with onRetryExhaustedThrow(BiFunction).
Additionally, to help dealing with bursts of transient errors in a long-lived Flux as if each burst had its own attempt counter, one can choose to set transientErrors(boolean) to true. The comparison to maxAttempts(long) will then be done with the number of subsequent attempts that failed without an onNext in between.
The RetrySpec is copy-on-write and as such can be stored as a "template" and further configured by different components without a risk of modifying the original configuration.

Author:

Simon Baslé

Nested Class Summary
- Nested classes/interfaces inherited from class reactor.util.retry.Retry
  Retry.RetrySignal

Field Summary

Fields
Modifier and Type	Field and Description
`Predicate<Throwable>`	`errorFilter` The configured `Predicate` to filter which exceptions to retry.
`boolean`	`isTransientErrors` The configured transient error handling flag.
`long`	`maxAttempts` The configured maximum for retry attempts.

Fields inherited from class reactor.util.retry.Retry
retryContext

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`RetrySpec`	`doAfterRetry(Consumer<Retry.RetrySignal> doAfterRetry)` Add synchronous behavior to be executed after the retry trigger is emitted in the companion publisher.
`RetrySpec`	`doAfterRetryAsync(Function<Retry.RetrySignal,Mono<Void>> doAsyncAfterRetry)` Add asynchronous behavior to be executed after the current retry trigger in the companion publisher, thus delaying the resulting retry trigger with the additional `Mono`.
`RetrySpec`	`doBeforeRetry(Consumer<Retry.RetrySignal> doBeforeRetry)` Add synchronous behavior to be executed before the retry trigger is emitted in the companion publisher.
`RetrySpec`	`doBeforeRetryAsync(Function<Retry.RetrySignal,Mono<Void>> doAsyncBeforeRetry)` Add asynchronous behavior to be executed before the current retry trigger in the companion publisher, thus delaying the resulting retry trigger with the additional `Mono`.
`RetrySpec`	`filter(Predicate<? super Throwable> errorFilter)` Set the `Predicate` that will filter which errors can be retried.
`Flux<Long>`	`generateCompanion(Flux<Retry.RetrySignal> flux)` The intent of the functional `Retry` class is to let users configure how to react to `Retry.RetrySignal` by providing the operator with a companion publisher.
`RetrySpec`	`maxAttempts(long maxAttempts)` Set the maximum number of retry attempts allowed.
`RetrySpec`	`modifyErrorFilter(Function<Predicate<Throwable>,Predicate<? super Throwable>> predicateAdjuster)` Allows to augment a previously `set` `Predicate` with a new condition to allow retries of some exception or not.
`RetrySpec`	`onRetryExhaustedThrow(BiFunction<RetrySpec,Retry.RetrySignal,Throwable> retryExhaustedGenerator)` Set the generator for the `Exception` to be propagated when the maximum amount of retries is exhausted.
`RetrySpec`	`transientErrors(boolean isTransientErrors)` Set the transient error mode, indicating that the strategy being built should use `Retry.RetrySignal.totalRetriesInARow()` rather than `Retry.RetrySignal.totalRetries()`.
`RetrySpec`	`withRetryContext(ContextView retryContext)` Set the user provided `context` that can be used to manipulate state on retries.

Methods inherited from class reactor.util.retry.Retry
backoff, fixedDelay, from, indefinitely, max, maxInARow, retryContext, withThrowable

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - maxAttempts
```
public final long maxAttempts
```
    The configured maximum for retry attempts.
    
    See Also:
    
    maxAttempts(long)
  - errorFilter
```
public final Predicate<Throwable> errorFilter
```
    The configured Predicate to filter which exceptions to retry.
    
    See Also:
    
    filter(Predicate), modifyErrorFilter(Function)
  - isTransientErrors
```
public final boolean isTransientErrors
```
    The configured transient error handling flag.
    
    See Also:
    
    transientErrors(boolean)
- Method Detail
  - withRetryContext
```
public RetrySpec withRetryContext(ContextView retryContext)
```
    Set the user provided context that can be used to manipulate state on retries.
    
    Parameters:
    
    retryContext - a new snapshot of user provided data
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - maxAttempts
```
public RetrySpec maxAttempts(long maxAttempts)
```
    Set the maximum number of retry attempts allowed. 1 meaning "1 retry attempt": the original subscription plus an extra re-subscription in case of an error, but no more.
    
    Parameters:
    
    maxAttempts - the new retry attempt limit
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as a Retry
  - filter
```
public RetrySpec filter(Predicate<? super Throwable> errorFilter)
```
    Set the Predicate that will filter which errors can be retried. Exceptions that don't pass the predicate will be propagated downstream and terminate the retry sequence. Defaults to allowing retries for all exceptions.
    
    Parameters:
    
    errorFilter - the predicate to filter which exceptions can be retried
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - modifyErrorFilter
```
public RetrySpec modifyErrorFilter(Function<Predicate<Throwable>,Predicate<? super Throwable>> predicateAdjuster)
```
    Allows to augment a previously set Predicate with a new condition to allow retries of some exception or not. This can typically be used with Predicate.and(Predicate) to combine existing predicate(s) with a new one.
    For example:
```
 //given
 RetrySpec retryTwiceIllegalArgument = Retry.max(2)
     .filter(e -> e instanceof IllegalArgumentException);

 RetrySpec retryTwiceIllegalArgWithCause = retryTwiceIllegalArgument.modifyErrorFilter(old ->
     old.and(e -> e.getCause() != null));
 
```
    Parameters:
    
    predicateAdjuster - a Function that returns a new Predicate given the currently in place Predicate (usually deriving from the old predicate).
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - doBeforeRetry
```
public RetrySpec doBeforeRetry(Consumer<Retry.RetrySignal> doBeforeRetry)
```
    Add synchronous behavior to be executed before the retry trigger is emitted in the companion publisher. This should not be blocking, as the companion publisher might be executing in a shared thread.
    
    Parameters:
    
    doBeforeRetry - the synchronous hook to execute before retry trigger is emitted
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
    
    See Also:
    
    andDelayRetryWith for an asynchronous version
  - doAfterRetry
```
public RetrySpec doAfterRetry(Consumer<Retry.RetrySignal> doAfterRetry)
```
    Add synchronous behavior to be executed after the retry trigger is emitted in the companion publisher. This should not be blocking, as the companion publisher might be publishing events in a shared thread.
    
    Parameters:
    
    doAfterRetry - the synchronous hook to execute after retry trigger is started
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
    
    See Also:
    
    andRetryThen for an asynchronous version
  - doBeforeRetryAsync
```
public RetrySpec doBeforeRetryAsync(Function<Retry.RetrySignal,Mono<Void>> doAsyncBeforeRetry)
```
    Add asynchronous behavior to be executed before the current retry trigger in the companion publisher, thus delaying the resulting retry trigger with the additional Mono.
    
    Parameters:
    
    doAsyncBeforeRetry - the asynchronous hook to execute before original retry trigger is emitted
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - doAfterRetryAsync
```
public RetrySpec doAfterRetryAsync(Function<Retry.RetrySignal,Mono<Void>> doAsyncAfterRetry)
```
    Add asynchronous behavior to be executed after the current retry trigger in the companion publisher, thus delaying the resulting retry trigger with the additional Mono.
    
    Parameters:
    
    doAsyncAfterRetry - the asynchronous hook to execute after original retry trigger is emitted
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - onRetryExhaustedThrow
```
public RetrySpec onRetryExhaustedThrow(BiFunction<RetrySpec,Retry.RetrySignal,Throwable> retryExhaustedGenerator)
```
    Set the generator for the Exception to be propagated when the maximum amount of retries is exhausted. By default, throws an Exceptions.retryExhausted(String, Throwable) with the message reflecting the total attempt index, transient attempt index and maximum retry count. The cause of the last Retry.RetrySignal is also added as the exception's cause.
    
    Parameters:
    
    retryExhaustedGenerator - the Function that generates the Throwable for the last Retry.RetrySignal
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - transientErrors
```
public RetrySpec transientErrors(boolean isTransientErrors)
```
    Set the transient error mode, indicating that the strategy being built should use Retry.RetrySignal.totalRetriesInARow() rather than Retry.RetrySignal.totalRetries(). Transient errors are errors that could occur in bursts but are then recovered from by a retry (with one or more onNext signals) before another error occurs.
    In the case of a simple count-based retry, this means that the maxAttempts(long) is applied to each burst individually.
    
    Parameters:
    
    isTransientErrors - true to activate transient mode
    
    Returns:
    
    a new copy of the RetrySpec which can either be further configured or used as Retry
  - generateCompanion
```
public Flux<Long> generateCompanion(Flux<Retry.RetrySignal> flux)
```
    Description copied from class: Retry
    
    The intent of the functional Retry class is to let users configure how to react to Retry.RetrySignal by providing the operator with a companion publisher. Any onNext emitted by this publisher will trigger a retry, but if that emission is delayed compared to the original signal then the attempt is delayed as well. This method generates the companion, out of a Flux of Retry.RetrySignal, which itself can serve as the simplest form of retry companion (indefinitely and immediately retry on any error).
    
    Specified by:
    
    generateCompanion in class Retry
    
    Parameters:
    
    flux - the original Flux of Retry.RetrySignal, notifying of each source error that might result in a retry attempt, with context around the error and current retry cycle.
    
    Returns:
    
    the actual companion to use, which might delay or limit retry attempts

Class RetrySpec

Nested Class Summary

Nested classes/interfaces inherited from class reactor.util.retry.Retry

Field Summary

Fields inherited from class reactor.util.retry.Retry

Method Summary

Methods inherited from class reactor.util.retry.Retry

Methods inherited from class java.lang.Object

Field Detail

maxAttempts

errorFilter

isTransientErrors

Method Detail

withRetryContext

maxAttempts

filter

modifyErrorFilter

doBeforeRetry

doAfterRetry

doBeforeRetryAsync

doAfterRetryAsync

onRetryExhaustedThrow

transientErrors

generateCompanion