Package ratpack.exec.util.retry

Class DurationRetryPolicy

java.lang.Object

ratpack.exec.util.retry.DurationRetryPolicy

All Implemented Interfaces:

RetryPolicy

public class DurationRetryPolicy
extends Object
implements RetryPolicy

A duration based implementation of RetryPolicy.

This strategy will signal end of retries when the elapsed time from the first error occurrence surpasses the configurable max duration, 30 seconds by default.

 import ratpack.exec.ExecResult;
 import ratpack.exec.Promise;
 import ratpack.exec.util.retry.DurationRetryPolicy;
 import ratpack.exec.util.retry.RetryPolicy;
 import ratpack.exec.util.retry.FixedDelay;
 import ratpack.test.exec.ExecHarness;
 import ratpack.test.internal.time.FixedWindableClock;

 import java.time.Duration;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;

 import static org.junit.jupiter.api.Assertions.assertEquals;

 public class Example {
   private static final List<String> LOG = new LinkedList<>();

   public static void main(String... args) throws Exception {
     AtomicInteger source = new AtomicInteger();
     FixedWindableClock clock = new FixedWindableClock(Instant.now(), ZoneOffset.UTC);

     RetryPolicy retryPolicy = DurationRetryPolicy.of(b -> b
       .delay(FixedDelay.of(Duration.ofMillis(500)))
       .maxDuration(Duration.ofSeconds(10))
       .clock(clock));

     RuntimeException e = new RuntimeException("!");

     Throwable result = ExecHarness.yieldSingle(exec ->
       Promise.sync(source::incrementAndGet)
         .mapIf(i -> i == 3, i -> {
           clock.windClock(Duration.ofMinutes(5));
           return i;
          })
         .map(i -> { throw new IllegalStateException(); })
         .retry(retryPolicy, (i, t) -> LOG.add("retry attempt: " + i))
     ).getThrowable();

     assertEquals("java.lang.IllegalStateException", result.getClass().getCanonicalName());
     assertEquals(Arrays.asList("retry attempt: 1", "retry attempt: 2"), LOG);
   }
 }
 

Since:

1.7

See Also:

DurationRetryPolicyBuilder

Constructor Summary

Constructors

Constructor	Description
DurationRetryPolicy(Delay delay, Duration maxDuration, Clock clock)

Method Summary

Modifier and Type	Method	Description
int	attempts()	Attempts performed so far.
Promise<Duration>	delay()	Promise that returns the waiting time before retrying.
RetryPolicy	increaseAttempt()	Increase number of attempts.
boolean	isExhausted()	If the caller should stop retrying.
static DurationRetryPolicy	of(Action<? super DurationRetryPolicyBuilder> definition)	Builds a new duration based retry policy from the given definition.

Methods inherited from class java.lang.Object

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

Constructor Detail

DurationRetryPolicy

public DurationRetryPolicy(Delay delay,
                           Duration maxDuration,
                           Clock clock)

Method Detail

of

public static DurationRetryPolicy of(Action<? super DurationRetryPolicyBuilder> definition)
                              throws Exception

Builds a new duration based retry policy from the given definition.

Parameters:

definition - the duration based retry policy definition

Returns:

a duration based retry policy

Throws:

Exception - any thrown by building the duration based retry policy

isExhausted

public boolean isExhausted()

If the caller should stop retrying.

Specified by:

isExhausted in interface RetryPolicy

Returns:

TRUE if the caller should stop retrying

attempts

public int attempts()

Attempts performed so far. Starts on 1, i.e. when no retry has been performed yet this returns 1.

Specified by:

attempts in interface RetryPolicy

Returns:

attempts performed so far.

delay

public Promise<Duration> delay()

Promise that returns the waiting time before retrying.

Specified by:

delay in interface RetryPolicy

Returns:

promise that returns the waiting time before retrying

See Also:

and its implementors for different strategies

increaseAttempt

public RetryPolicy increaseAttempt()

Increase number of attempts.

Specified by:

increaseAttempt in interface RetryPolicy

Returns:

this policy after updating the internal state around attempts