You made a typical Spring AOP beginners' mistake: You forgot that proxy-based AOP only works if proxy methods are called from outside, not via this (avoiding the proxy). But the internal call inTry() is the same as this.inTry(). Thus, the aspect never triggers for inTry and you have to rearrange your code like this:
package spring.aop;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.TimeUnit;
@RestController("/")
public class HomeController {
static int counter = 0;
@RequestMapping
@RetryOnFailure(attempts = 3, delay = 2, unit = TimeUnit.SECONDS)
public String index() {
throw new RuntimeException("Exception in try " + ++counter);
}
}
I also changed the aspect a little bit so as to
- avoid reflection and bind the annotation to an advice parameter directly via
@annotation(),
- log the joinpoint when the advice is triggered and
- return "OK" on try #3 (just for fun, not necessary).
package spring.aop;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
@Aspect
@Component
public final class MethodRepeater {
@Around("execution(* spring.aop..*(..)) && @annotation(retryOnFailure)")
public Object wrap(final ProceedingJoinPoint joinPoint, RetryOnFailure retryOnFailure) throws Throwable {
System.out.println(joinPoint);
return proceed(joinPoint, retryOnFailure);
}
private Object proceed(ProceedingJoinPoint joinPoint, RetryOnFailure retryOnFailure) throws Throwable {
int attempt = 1;
while (true) {
try {
return joinPoint.proceed();
} catch (final Throwable ex) {
System.out.println("Try #" + attempt + " failed: " + ex);
if (++attempt >= retryOnFailure.attempts())
return "OK";
if (retryOnFailure.delay() > 0L)
retryOnFailure.unit().sleep(retryOnFailure.delay());
}
}
}
}
Now it works and the console log says:
execution(String spring.aop.HomeController.index())
Try #1 failed: java.lang.RuntimeException: Exception in try 1
Try #2 failed: java.lang.RuntimeException: Exception in try 2
inTry()always throws an exception. Does that make any sense? – Taco