Stability: Retry pattern

http://docs.spring.io/spring-batch/trunk/reference/html/retry.html
To make processing more robust and less prone to failure, sometimes it helps to automatically retry a failed operation in case it might succeed on a subsequent attempt. Errors that are susceptible to this kind of treatment are transient in nature.

http://fahdshariff.blogspot.com/2013/02/retrying-operations-using-springs.html

If your application is using Spring then it is easier to use the Spring Framework's RetryTemplate.

The example below shows how you can use a RetryTemplate to lookup a remote object. If the remote call fails, it will be retried five times with exponential backoff.

// import the necessary classes import org.springframework.batch.retry.RetryCallback; import org.springframework.batch.retry.RetryContext; import org.springframework.batch.retry.backoff.ExponentialBackOffPolicy; import org.springframework.batch.retry.policy.SimpleRetryPolicy; import org.springframework.batch.retry.support.RetryTemplate; ... // create the retry template final RetryTemplate template = new RetryTemplate(); template.setRetryPolicy(new SimpleRetryPolicy(5)); final ExponentialBackOffPolicy backOffPolicy = new ExponentialBackOffPolicy(); backOffPolicy.setInitialInterval(1000L); template.setBackOffPolicy(backOffPolicy); // execute the operation using the retry template template.execute(new RetryCallback<Remote>() {   @Override   public Remote doWithRetry(final RetryContext context) throws Exception {     return (Remote) Naming.lookup("rmi://somehost:2106/MyApp");   } });

http://www.mscharhag.com/spring/spring-retry
@EnableRetry

@Service

public class MyService {

 

  @Retryable(value = {FooException.class, BarException.class}, maxAttempts = 5)

  public void retryWithException() {

    // perform operation that is likely to fail

  }

 

  @Recover

  public void recover(FooException exception) {

    // recover from FooException

  }

}

Here we tell Spring to apply retry handling only if a Exception of type FooException or BarException is thrown. Other exceptions will not cause a retry. maxAttempts = 5 tells Spring to retry the method up to 5 times if it fails.

With @Recover we define a separate recovery method for FooException. This allows us to run special recovery code when a retryable method fails with FooException.

http://stackoverflow.com/questions/32324172/specifying-an-exception-specific-backoff-policy-with-spring-retry

Indeed, ExceptionClassifierRetryPolicy is the way to go. I didn't manage to make it work with the policyMap though. Here is how I've used it :

@Component("yourRetryPolicy")
public class YourRetryPolicy extends ExceptionClassifierRetryPolicy
{
    @PostConstruct
    public void init()
    {
        final SimpleRetryPolicy simpleRetryPolicy = new SimpleRetryPolicy();
        simpleRetryPolicy.setMaxAttempts( 3 );

        this.setExceptionClassifier( new Classifier<Throwable, RetryPolicy>()
        {
            @Override
            public RetryPolicy classify( Throwable classifiable )
            {
                    if ( classifiable instanceof YourException )
                    {
                            return new NeverRetryPolicy();
                    }
                    // etc...
                    return simpleRetryPolicy;
                }
            } );
        }

Then, you just have to set it on the retry template :

@Autowired
@Qualifier("yourRetryPolicy")
private YourRetryPolicy yourRetryPolicy;

//...

RetryTemplate retryTemplate = new RetryTemplate();
retryTemplate.setRetryPolicy( yourRetryPolicy );

http://ilkerkonar.blogspot.com/2015/01/spring-retry-sample.html

Cluster cluster = Cluster.builder()


.addContactPoint("127.0.0.1")


.withRetryPolicy(DowngradingConsistencyRetryPolicy.INSTANCE)


.build();

Cassandra: Datastax Java driver retry policy

[Java Tip] Retrying operation with Guava Retrying

Retryer<Boolean> retrier = RetryerBuilder.<Boolean>newBuilder()

02..retryIfExceptionOfType(TimeoutException.class)

03..retryIfRuntimeException()

04..withStopStrategy(StopStrategies.stopAfterAttempt(3))

05..build();


retrier.call(new UrlFetcher("http://www.google.com", "normal"));
retrier.call(new UrlFetcher("http://www.doesnotexist.com", "fail"));