Using custom annotations with Spring AOP

[uvdoctor]

I am developing a web application that uses Spring MVC, Spring Services and Spring AOP. As a part of that, there is a logging aspect using Spring AOP that has before, afterReturning and afterThrowing methods. Also, there are few custom method-level annotations such as @DoNotLog and @LogExceptionAsWarning that I want to use in the aspect to see if logging should be done and if an exception should be logged as a warning. I tried to check for these annotations at run time using isAnnotationPresent method on a "Method" object, but it does not work.

It seems to me that as the objects generated by Spring are proxy objects and not the objects that I have coded, the annotations declared on these methods are lost during aspect weaving. However, the weird part is that, during logging, it does show entries for the classes that I have coded.

Looking forward to advise.

[gschmutz]

Hi

I think you should try to include your annotation in the pointcut definition itself. Since Spring 2.0 you can use the @AspectJ style to declare your aspects.

Here is a someway contrived example, but hope it helps.

I have an After Throwing Adivce which handles exceptions from the application and sends them via email to a receiver.

@Aspect
public class MailNotificationAspect {
	private Mailer mailer;

	public void setMailer(Mailer mailer) {
		this.mailer = mailer;
	}
	
	@Pointcut("execution(* *.*(..)) && @within(com.trivadis.issuesmgmt.aop.Mail) && @annotation(m) ")
	public void inApplication(Mail m) {}	

	@AfterThrowing(pointcut="inApplication(m)",throwing="ex")
	public void afterThrowingWithSubject(Exception ex, Mail m) throws Throwable {
		mailer.send(ex, m.subject());
	}
}

Here is a service which throws an exception if the paramter is null.

@Mail
public class PersonMgmtServiceImpl implements PersonMgmtService 
{
...
	@Mail(subject="This is the test subject")
	public void createPerson(Person person) throws ApplicationException {
		if (person == null) {
			throw new ApplicationException();
		}
		personDAO.save(person);
	}
...

With the annotation Mail on class level, I specify that a mail should be sent whenever a method in the class throws an exception and with the annotation on method level I can overwrite the subject being used in the mail message.

the imporant part in the aspect above is the pointcut declaration:

@Pointcut("execution(* *.*(..)) && @within(com.trivadis.issuesmgmt.aop.Mail) && @annotation(m) ")
public void inApplication(Mail m) {}

This reads as "all executions of any @Mail annotated methods where the declared type of the target object (the class) has an @Mail annotation".
By using @annotation(m) I'm using the binding form and bind it as a parameter to the advice

@AfterThrowing(pointcut="inApplication(m)",throwin g="ex")
public void afterThrowingWithSubject(Exception ex, Mail m) throws Throwable {
mailer.send(ex, m.subject());
}

Hope this helps.

One last thing you need to be aware of. Annotations on methods are not inherited, so if your on class level, you won't see a method-level annotation defined in an interface.