RetryAspect v1.0.0

RetryAspect Class

This RetryAspect class is an implementation of the retry mechanism in Java using Aspect-Oriented Programming (AOP). It allows methods annotated with @Retryable to be executed multiple times in case of failure, with configurable retry attempts and backoff delay.

Features

• Retry Mechanism: Automatically retries a method execution if it fails, based on the configuration provided by the @Retryable annotation.
• Configurable Attempts and Delay: Allows configuration of the maximum number of retry attempts and the delay between retries.
• Exception Handling: Only retries for specified exceptions, providing fine-grained control over which failures should trigger a retry.

Usage

To use the RetryAspect class, follow these steps:

1. Annotate Methods with @Retryable

Annotate the methods you want to be retryable with the @Retryable annotation.

import com.cmccarthy.annotations.Retryable;

public class MyService {
    @Retryable(maxAttempts = 3, backoff = @Backoff(delay = 1000), include = {RuntimeException.class})
    public void performTask() {
        // Method implementation
    }
}

2. Configure the @Retryable Annotation

The @Retryable annotation allows you to configure the retry behavior for a method. It has the following attributes:

• maxAttempts: The maximum number of retry attempts (default is 3).
• backoff: Specifies the backoff policy, including the delay between retries.
• include: The exceptions that should trigger a retry.

@Retryable(maxAttempts = 5, backoff = @Backoff(delay = 2000), include = {IOException.class})
public void unreliableMethod() {
// Method implementation
}

In this example, the unreliableMethod will be retried up to 5 times with a delay of 2000 milliseconds between retries, but only if an IOException is thrown.

Class Details RetryAspect Class

The RetryAspect class contains the AOP logic for handling retries.

@Aspect
public class RetryAspect {

    @Pointcut("@annotation(retryable) && execution(* *(..))")
    public void retryableMethods(Retryable retryable) {
    }

    @Around(value = "retryableMethods(retryable)", argNames = "joinPoint,retryable")
    public Object retryMethod(ProceedingJoinPoint joinPoint, Retryable retryable) throws Throwable {
        int maxAttempts = retryable.maxAttempts();
        long delay = retryable.backoff().delay();
        int attempts = 0;
        Throwable lastException = null;

        while (attempts < maxAttempts) {
            try {
                return joinPoint.proceed();
            } catch (Throwable ex) {
                lastException = ex;
                if (!isExceptionIncluded(ex, retryable.include())) {
                    throw ex;
                }
                attempts++;
                if (attempts < maxAttempts) {
                    Thread.sleep(delay);
                }
            }
        }
        throw lastException != null ? lastException : new RuntimeException("Retry failed after max attempts");
    }

    private boolean isExceptionIncluded(Throwable ex, Class<? extends Throwable>[] includedClasses) {
        for (Class<? extends Throwable> includedClass : includedClasses) {
            if (includedClass.isInstance(ex)) {
                return true;
            }
        }
        return false;
    }
}

Methods

• retryableMethods: Pointcut definition for methods annotated with @Retryable.
• retryMethod: Around advice that handles the retry logic.
• isExceptionIncluded: Helper method to check if an exception is included in the list of retryable exceptions.

Dependencies

Ensure that you have the necessary dependencies for AspectJ in your project

    <dependencies>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.9.7</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.7</version>
        </dependency>
    </dependencies>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>aspectj-maven-plugin</artifactId>
            <version>1.15.0</version>
        </plugin>
    </plugins>

Contribute

Contributions are welcome! Here's how you can get started!!

License

This project is licensed under the MIT License - see the LICENSE file for details.

Full Changelog: https://github.com/cmccarthyIrl/RetryAspect/commits/retry-aspect-1.0.0

Full Changelog: https://github.com/cmccarthyIrl/RetryAspect/commits/RetryAspect-v1.0.0