Introduction to AspectJ 5 with Spring and JavaConfig

Using the articles about JavaConfig in Guice vs. Spring JavaConfig: A comparison of DI styles and Simplifying Enterprise Applications with Spring 2.0 and AspectJ I managed to use aspectj configured with spring in java code only, that is without using xml files.

Here is the annotated aspectj class:

import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class HelloFromAspectJ {
    @Pointcut("execution(* main(..))")
    public void mainMethod() {}

    @AfterReturning("mainMethod()")
    public void sayHello() {
        System.out.println("Hello from AspectJ!");
    }
}

Here is the ordinary java class which is adviced by the above aspect:

public class HelloService {
    public void main() {
        System.out.println("Hello World!");
    }
}

And here is the configuration class, which replaced the spring's configuration xml file:

import org.springframework.config.java.annotation.Configuration;
import org.springframework.config.java.annotation.Bean;
import org.springframework.config.java.context.AnnotationApplicationContext;
import org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator;
import org.springframework.context.ApplicationContext;

@Configuration
public class SpringConfig {
    @Bean
    public HelloService helloService() {
        return new HelloService();
    }
    @Bean
    public HelloFromAspectJ helloFromAspectJ() {
        return new HelloFromAspectJ();
    }
    @Bean
    public AnnotationAwareAspectJAutoProxyCreator annotationAwareAspectJAutoProxyCreator() {
        return new AnnotationAwareAspectJAutoProxyCreator();
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new AnnotationApplicationContext(SpringConfig.class);
        HelloService helloService = (HelloService) ctx.getBean("helloService");
        helloService.main();
    }
}

Note that the bean AnnotationAwareAspectJAutoProxyCreator is the enabler of annotated aspects in spring. It has the same function as the

<aop:aspectj-autoproxy/>

element in the spring's xml configuration.