@AspectJ切入点覆盖带有注释的接口方法的方法 [英] @AspectJ pointcut for methods that override an interface method with an annotation

问题描述

如何编写适用于覆盖带注释的接口方法的方法执行的aspectj切入点？例如：

How can I write an aspectj pointcut that applies to method executions which override an interface method with an annotation? For example:

interface A {
  @MyAnnotation void method();
}
class B implements A {
  void method();
}

切入点执行（@MyAnnotation * *。* （..））仅匹配 B.method（）带有注释本身。有没有其他方法可以做到这一点？

The pointcut execution(@MyAnnotation * *.*(..)) does only match if B.method() carries the annotation itself. Is there another way to do this?

推荐答案

正如尼古拉斯指出的那样，这在AspectJ中是不可能的。这里有更多证据证明为什么不可能（取自 http://www.eclipse.org/aspectj/doc/released/adk15notebook/annotations-pointcuts-and-advice.html 部分注释继承和切入点匹配）：

As Nicholas pointed out, this is not possible in AspectJ. Here is more proof of why it is not possible (taken from http://www.eclipse.org/aspectj/doc/released/adk15notebook/annotations-pointcuts-and-advice.html section Annotation Inheritance and pointcut matching):

根据Java 5规范，非类型注释不会被继承，类型注释只有在具有@Inherited元注释的情况下才会被继承。对c2.aMethod的调用（在您的示例中将是b.method（））不匹配，因为修饰符的连接点匹配（visibility modifiers，annotations和throws子句）基于连接点的主题（方法实际被调用）。

According to the Java 5 specification, non-type annotations are not inherited, and annotations on types are only inherited if they have the @Inherited meta-annotation. The call to c2.aMethod (that would be b.method() in your example) is not matched because join point matching for modifiers (the visibility modifiers, annotations, and throws clause) is based on the subject of the join point (the method actually being called).

遇到同样的问题，我写了一个小方法/库，可以让你写这种方法的切入点。以下是它如何适用于您的示例：

Having suffered from this same issue, I have written a small method/library that would allow you to write pointcuts for such methods. Here is how it would work for your example:

myAnnotationIsExecuted(): execution(public * *.*(..)) && 
             if(implementsAnnotation("@MyAnnotation()", thisJoinPoint));

OR

myAnnotationIsExecuted(): execution(public * A+.*(..)) &&
             if(implementsAnnotation("@MyAnnotation()", thisJoinPoint));

方法 implementsAnnotation（String，JoinPoint）来自图书馆;检查实现的方法是否包含指定注释的基本方法。

The method implementsAnnotation(String,JoinPoint) is coming from the library; a basic method that checks if the implemented methods contain the specified annotation.

可以找到有关方法/库的更多信息此处。

More information about the method/library can be found here.

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