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springaspectjspring-annotations

Spring AspectJ Custom Annotation for Logging

I have defined a custom annotation as below.

package com.xyz;
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Loggable {
    String message() default "Log Message";
}

My aspect class contains the below method:

@Around(value = "@annotation(com.xyz.Loggable)")
public void logAround(ProceedingJoinPoint joinPoint) throws Throwable {
    // come code here
}

My service interface is as below.

public interface Service {
   @Loggable
   public void method1();
}

My implementation is as below.

public class ServiceImpl implements Service {
     public void method1() {
         // some code here
     }
}

With this setup, My advice is not getting triggered. (however it gets triggered if i move the @Loggable annotation to method1() in ServiceImpl class).

I would like to keep the annotation defined at interface level instead of method implementations. Is there a way to get this work ?

Solution

  • No, that is not possible (yet?).

    Annotations can only be inherited among Classes and even then only if they are themselves annotated with the meta-Annotation @Inherited:

    http://docs.oracle.com/javase/8/docs/api/java/lang/annotation/Inherited.html

    It is not possible to have annotations on Interfaces be inherited to their implementing classes.

    This is also explained in the AspectJ documentation: http://www.eclipse.org/aspectj/doc/released/adk15notebook/annotations.html#annotation-inheritance

    @Inherited annotations are not inherited when used to annotate anything other than a type. A type that implements one or more interfaces never inherits any annotations from the interfaces it implements.