Re: [aspectj-users] Exposing state held in method annotations

["Wes Isberg" <wes@xxxxxxxxxxxxxx>]

Hi Eric -

> But how can I expose the "value" state "{1}" that I passed in above?
> The following does *not* work:
> 
> pointcut constantArgumentMethods(int[] value) :
> call(@ConstantArguments(value) * *.*(..));

@withincode() should surface a method annotation, but 1.5.0M1 
doesn't yet support binding (and also fails to compile when a 
literal type is used).

Java 5 should permit you to reflectively read the annotation on a method.
Code for that is below, but looks broken: when annotations are added 
to methods, they no longer are returned by Class.getMethod*(..)
(true of both javac and jdt, so my code could be wrong - corrections?)

See the developer's notebook section on runtime matching and context
exposure for annotations:
http://dev.eclipse.org/viewcvs/indextech.cgi/~checkout~/aspectj-home/doc/ajdk15notebook/annotations-pointcuts-and-advice.html#d0e1169

Wes

https://bugs.eclipse.org/bugs/show_bug.cgi?id=83875

------------ misc/MAI.java
package misc;

import java.lang.reflect.Method;
import java.lang.annotation.*;
import java.util.Arrays;

/**
 * MAI: method annotation instance
 */
public class MAI {

    public static void main(String[] args) {
    	m();
    	getMethodAnnotation();
    }
    
    @CConstantArguments(id=1)
    static void m() {
        System.out.println("in m()");
    }

    static int getMethodAnnotation() {
    	try {
        	Class c = MAI.class;
        	Method[] ms = c.getMethods();
        	System.out.println("" + Arrays.asList(ms));
        	Method m = c.getMethod("m", new Class[0]);
        	CConstantArguments ca = m.getAnnotation(CConstantArguments.class);
    		return (null == ca ? -1 : ca.id());
    	} catch (Exception e) {
    		throw new Error(e);
    	}
    }
}
@Retention(RetentionPolicy.RUNTIME)
@interface CConstantArguments {
   int id();
}


> ------------Original Message------------
> From: Eric Bodden <eric@xxxxxxxxx>
> To: aspectj-users@xxxxxxxxxxx
> Date: Thu, Jan-27-2005 10:26 AM
> Subject: [aspectj-users] Exposing state held in method annotations
>
>  
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Hi all.
> 
> Today I came across an annotation problem which I don't know how to
> solve:
> 
> I have a method annotated like this:
> 
> @ConstantArguments({1}) public int foo(Wrapper a) {
> ..
> }
> 
> Now I am matching on calls to it like this:
> 
> pointcut constantArgumentMethods() : call(@ConstantArguments *
> *.*(..));
> 
> But how can I expose the "value" state "{1}" that I passed in above?
> The following does *not* work:
> 
> pointcut constantArgumentMethods(int[] value) :
> call(@ConstantArguments(value) * *.*(..));
> 
> I guess @target will not help, since it returns annotations of the
> target *type*, not *method*, or am I wrong?
> 
> Cheers,
> Eric
> 
> P.S. Definition of the ynnotation type:
> 
> public @interface ConstantArguments {
> 
>     int[] value() default {};
>     
> }
> 
> - -- 
> Eric Bodden
> Chair I2 for Programming Languages and Program Analysis
> RWTH Aachen University
> 
> -----BEGIN PGP SIGNATURE-----
> Version: PGP 8.0.3
> 
> iQA/AwUBQfkyNMwiFCm7RlWCEQJUvwCdF6oPnnOj0IOrwgK3oqBFsEG+f+EAn1lW
> n+BcQ4OfJRo3KlGuMlt7q+3Y
> =IJhX
> -----END PGP SIGNATURE-----
> 
> 
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@xxxxxxxxxxx
> http://dev.eclipse.org/mailman/listinfo/aspectj-users
>