RetryAspect

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.

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

In this example, performTask will make up to 3 total attempts (1 initial + 2 retries) with a delay of 1000 milliseconds between retries, but only if a RuntimeException is thrown.

Note: Methods should be idempotent as they may be executed multiple times.

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, unreliableMethod will make up to 5 total attempts (1 initial + 4 retries) with a delay of 2000 milliseconds between retries, but only if an IOException is thrown.

Important Configuration Notes

• maxAttempts: Must be at least 1. Represents total attempts (initial + retries)
• include: Cannot be empty. Must specify at least one exception type to retry
• delay: Must be non-negative (in milliseconds)
• multiplier: Use values > 1.0 for exponential backoff, 1.0 for fixed delay

Usage

To use the RetryAspect library in your project, include the following dependencies and plugins in your pom.xml file:

1. Add retryaspect as a dependency

<dependencies>
    ...
    <dependency>
        <groupId>io.github.cmccarthyirl</groupId>
        <artifactId>retryaspect</artifactId>
        <version>1.0.5</version>
    </dependency>
    ...
</dependencies>

2. Configure the AspectJ Maven Plugin

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>aspectj-maven-plugin</artifactId>
            <version>1.15.0</version>
            <configuration>
                <complianceLevel>16.0</complianceLevel>
                <source>16.0</source>
                <target>16.0</target>
                <showWeaveInfo>true</showWeaveInfo>
                <verbose>true</verbose>
                <Xlint>ignore</Xlint>
                <encoding>UTF-8</encoding>
                <aspectLibraries>
                    <aspectLibrary>
                        <groupId>io.github.cmccarthyirl</groupId>
                        <artifactId>retryaspect</artifactId>
                    </aspectLibrary>
                </aspectLibraries>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <!-- use this goal to weave all your main classes -->
                        <goal>compile</goal>
                        <!-- use this goal to weave all your test classes -->
                        <goal>test-compile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Contribute

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

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.