Various pointcut expression scopes trigger multiple advice calls unexpectedly

Question

Background

Logging a project using aspects such that all methods, classes, and constructors that are marked with the @Log annotation have information written to a log file.

Problem

Methods appear to be called recursively one-level deep, but the code does not show any such recursive relationship.

Actual

Logged results:

2018-09-25 12:17:29,155 |↷|   EmailNotificationServiceBean#createPayload([SECURE])
2018-09-25 12:17:29,155 |↷|     EmailNotificationServiceBean#createPayload([{service.notification.smtp.authentication.password=password, mail.smtp.port=25, service.notification.smtp.authentication.username=dev@localhost, mail.mime.allowutf8=true, mail.smtp.auth=false, mail.smtp.starttls.enable=false, mail.smtp.timeout=10000, mail.smtp.host=localhost}])
2018-09-25 12:17:29,193 |↷|       EmailPayloadImpl#<init>([{service.notification.smtp.authentication.password=password, mail.smtp.port=25, service.notification.smtp.authentication.username=dev@localhost, mail.mime.allowutf8=true, mail.smtp.auth=false, mail.smtp.starttls.enable=false, mail.smtp.timeout=10000, mail.smtp.host=localhost}])
2018-09-25 12:17:29,193 |↷|         EmailPayloadImpl#validate([SECURE])
2018-09-25 12:17:29,194 |↷|           EmailPayloadImpl#validate([{service.notification.smtp.authentication.password=password, mail.smtp.port=25, service.notification.smtp.authentication.username=dev@localhost, mail.mime.allowutf8=true, mail.smtp.auth=false, mail.smtp.starttls.enable=false, mail.smtp.timeout=10000, mail.smtp.host=localhost}, SMTP connection and credentials])
2018-09-25 12:17:29,195 |↷|         EmailPayloadImpl#setMailServerSettings([SECURE])
2018-09-25 12:17:29,196 |↷|           EmailPayloadImpl#setMailServerSettings([{service.notification.smtp.authentication.password=password, mail.smtp.port=25, service.notification.smtp.authentication.username=dev@localhost, mail.mime.allowutf8=true, mail.smtp.auth=false, mail.smtp.starttls.enable=false, mail.smtp.timeout=10000, mail.smtp.host=localhost}])

Expected

Expected logged results:

2018-09-25 12:17:29,155 |↷|   EmailNotificationServiceBean#createPayload([SECURE])
2018-09-25 12:17:29,193 |↷|     EmailPayloadImpl#<init>([SECURE])
2018-09-25 12:17:29,193 |↷|       EmailPayloadImpl#validate([SECURE])
2018-09-25 12:17:29,195 |↷|       EmailPayloadImpl#setMailServerSettings([SECURE])

Code

The logging aspect:

@Aspect
public class LogAspect {
    @Pointcut("execution(public @Log( secure = true ) *.new(..))")
    public void loggedSecureConstructor() { }

    @Pointcut("execution(@Log( secure = true ) * *.*(..))")
    public void loggedSecureMethod() { }

    @Pointcut("execution(public @Log( secure = false ) *.new(..))")
    public void loggedConstructor() { }

    @Pointcut("execution(@Log( secure = false ) * *.*(..))")
    public void loggedMethod() { }

    @Pointcut("execution(* (@Log *) .*(..))")
    public void loggedClass() { }

    @Around("loggedSecureMethod() || loggedSecureConstructor()")
    public Object logSecure(final ProceedingJoinPoint joinPoint) throws Throwable {
        return log(joinPoint, true);
    }

    @Around("loggedMethod() || loggedConstructor() || loggedClass()")
    public Object log(final ProceedingJoinPoint joinPoint) throws Throwable {
        return log(joinPoint, false);
    }

    private Object log(final ProceedingJoinPoint joinPoint, boolean secure) throws Throwable {
        final Signature signature = joinPoint.getSignature();
        final Logger log = getLogger(signature);

        final String className = getSimpleClassName(signature);
        final String memberName = signature.getName();
        final Object[] args = joinPoint.getArgs();
        final CharSequence indent = getIndentation();
        final String params = secure ? "[SECURE]" : Arrays.deepToString(args);

        log.trace("\u21B7| {}{}#{}({})", indent, className, memberName, params);

        try {
            increaseIndent();

            return joinPoint.proceed(args);
        } catch (final Throwable t) {
            final SourceLocation source = joinPoint.getSourceLocation();
            log.warn("\u2717| {}[EXCEPTION {}] {}", indent, source, t.getMessage());
            throw t;
        } finally {
            decreaseIndent();
            log.trace("\u21B6| {}{}#{}", indent, className, memberName);
        }
    }

The Log interface definition:

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE, ElementType.CONSTRUCTOR})
public @interface Log {
    boolean secure() default false;
}

The decompiled service bean:

@Log
public class EmailNotificationServiceBean
implements EmailNotificationService {

    @Log(secure = true)
    @Override
    public EmailPayload createPayload(Map<String, Object> settings) throws NotificationServiceException {
        Map<String, Object> map = settings;
        JoinPoint joinPoint = Factory.makeJP((JoinPoint.StaticPart)ajc$tjp_2, (Object)this, (Object)this, map);
        Object[] arrobject = new Object[]{this, map, joinPoint};
        return (EmailPayload)LogAspect.aspectOf().logSecure(new EmailNotificationServiceBean$AjcClosure7(arrobject).linkClosureAndJoinPoint(69648));
    }

The payload implementation:

@Log
public class EmailPayloadImpl extends AbstractPayload implements EmailPayload {

    @Log(secure = true)
    public EmailPayloadImpl(final Map<String, Object> settings)
                    throws NotificationServiceException {
        validate(settings, "SMTP connection and credentials");
        setMailServerSettings(settings);
    }

    @Log(secure = true)
    private void validate(final Map<String, Object> map, final String message)
                    throws NotificationServiceException {
        if (map == null || map.isEmpty()) {
            throwException(message);
        }
    }

    @Log(secure = true)
    private void setMailServerSettings(final Map<String, Object> settings) {
        this.mailServerSettings = settings;
    }

Question

What is causing:

• the secure = true constructor annotation attribute to be ignored; and
• the validate and setMailServerSettings methods to be called and logged twice (once securely and once not)?

I suspect the issues are related.

Answer 1

Solution:

To fix duplication issue need to adjust loggedClass() pointcut definition:

@Pointcut("execution(* (@Log *) .*(..)) && !@annotation(Log)")
public void loggedClass() { }

Please also find a link to Proof of concept in the Additional information section.

---

Explanation:

Issue related to join points (defined by @Pointcut annotation), their patterns cross each other - and this is the reason of duplication in the logs.

In our case all @Pointcuts named descriptive enough, e.g.:

• loggedClass() covers all methods in the classes annotated by @Log.
• loggedSecureMethod() covers all methods annotated by @Log(secure = true). Others remain are similar to this one, so let's ignore them for explanation.

So in case when EmailPayloadImpl is annotated with @Log and EmailPayloadImpl.validate() is annotated with @Log(secure = true) - we will have 2 active join points: one secure and one non-secure. And this will cause adding 2 log entries.

---

Assuming that we want to introduce priority in the annotations, i.e. method-level annotation should overwrite class-level one - the simplest way will be just to avoid crossing join point patterns.

So we will need to have 3 groups for methods:

1. Methods annotated with @Log(secure = true) = loggedSecureMethod()
2. Methods annotated with @Log = loggedMethod()

3. Methods without @Log annotation, but within a class annotated with @Log, which is:

   @Pointcut("execution(* (@Log *) .*(..)) && !@annotation(Log)")
   public void loggedClass() { }
   

---

Additional information:

1. In case it will be needed to handle also @Log(secure = true) on the class level - need to add additional join point similar to loggedClass() of course.
2. Added Proof of concept >> in the GitHub