What are some examples of using Resilience4j in Java applications?

What are some examples of using Resilience4j in Java applications?

Resilience4j is a lightweight fault tolerance library for Java. Here are a few examples of its usage:

1. Circuit Breaker: Prevents calls to a service that is likely to fail, allowing for fallback methods.
2. Rate Limiter: Controls the rate of requests to a service to prevent overload.
3. Retry: Automatically retries failed calls to a service a specified number of times.
4. Bulkhead: Isolates failures in a part of the system to prevent cascading failures.

Can you show me a code example for the Circuit Breaker?

Sure! Here's a simple example of using Circuit Breaker in Resilience4j:

CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("myCircuitBreaker");

Supplier<String> decoratedSupplier = CircuitBreaker.decorateSupplier(circuitBreaker, () -> {
    // Call to external service
    return externalService.call();
});

String result = Try.ofSupplier(decoratedSupplier)
    .recover(throwable -> "Fallback response");

What about the Rate Limiter?

Here's an example of using Rate Limiter:

RateLimiter rateLimiter = RateLimiter.of("myRateLimiter", RateLimiterConfig.custom()
    .limitForPeriod(10)
    .limitRefreshPeriod(Duration.ofSeconds(1))
    .build());

Supplier<String> decoratedSupplier = RateLimiter.decorateSupplier(rateLimiter, () -> {
    // Call to external service
    return externalService.call();
});

String result = Try.ofSupplier(decoratedSupplier)
    .recover(throwable -> "Rate limit exceeded");