Around advice

Definition

An @Around advice runs code before and after a method call and decides whether the method runs at all. It is how you add timing, logging or retries to many methods without editing them.

Example code

Timing every call of a service

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

@Service
class PriceService {
    int priceOf(String item) { return item.length() * 10; }
}

@Aspect
@Component
class LoggingAspect {
    @Around("execution(* PriceService.*(..))")                   // every method of PriceService
    Object log(ProceedingJoinPoint call) throws Throwable {
        System.out.println("before " + call.getSignature().getName());
        Object result = call.proceed();                           // run the real method
        System.out.println("after, result = " + result);
        return result;
    }
}

@ComponentScan
@EnableAspectJAutoProxy
class Demo {
    public static void main(String[] args) {
        try (var context = new AnnotationConfigApplicationContext(Demo.class)) {
            context.getBean(PriceService.class).priceOf("book");
        }
    }
}

// Output:
// before priceOf
// after, result = 40