Spring AOP pointcut that matches annotation on interface

Question

I have a service class implemented in Java 6 / Spring 3 that needs an annotation to restrict access by role.

I have defined an annotation called RequiredPermission that has as its value attribute one or more values from an enum called OperationType:

public @interface RequiredPermission {  /**  * One or more {@link OperationType}s that map to the permissions required  * to execute this method.  *   * @return  */ OperationType[] value();}  public enum OperationType {       TYPE1,       TYPE2; }  package com.mycompany.myservice; public interface MyService{    @RequiredPermission(OperationType.TYPE1)    void myMethod( MyParameterObject obj ); }  package com.mycompany.myserviceimpl; public class MyServiceImpl implements MyService{    public myMethod( MyParameterObject obj ){        // do stuff here    } } 

I also have the following aspect definition:

/**  * Security advice around methods that are annotated with  * {@link RequiredPermission}.  *   * @param pjp  * @param param  * @param requiredPermission  * @return  * @throws Throwable  */ @Around(value = "execution(public *"         + " com.mycompany.myserviceimpl.*(..))"         + " && args(param)" + // parameter object         " && @annotation( requiredPermission )" // permission annotation  , argNames = "param,requiredPermission") public Object processRequest(final ProceedingJoinPoint pjp,         final MyParameterObject param,         final RequiredPermission requiredPermission) throws Throwable {     if(userService.userHasRoles(param.getUsername(),requiredPermission.values()){         return pjp.proceed();     }else{         throw new SorryButYouAreNotAllowedToDoThatException(             param.getUsername(),requiredPermission.value());     } } 

The parameter object contains a user name and I want to look up the required role for the user before allowing access to the method.

When I put the annotation on the method in MyServiceImpl, everything works just fine, the pointcut is matched and the aspect kicks in. However, I believe the annotation is part of the service contract and should be published with the interface in a separate API package. And obviously, I would not like to put the annotation on both service definition and implementation (DRY).

I know there are cases in Spring AOP where aspects are triggered by annotations one interface methods (e.g. Transactional). Is there a special syntax here or is it just plain impossible out of the box.

PS: I have not posted my spring config, as it seems to be working just fine. And no, those are neither my original class nor method names.

PPS: Actually, here is the relevant part of my spring config:

<aop:aspectj-autoproxy proxy-target-class="false" />  <bean class="com.mycompany.aspect.MyAspect">     <property name="userService" ref="userService" /> </bean> 

Answer 1

If I understand you correct, you want a pointcut that finds all methods in classes that extends MyService and is annotated and with the preferred arguments.

I propose that you replace:

execution(public * com.mycompany.myserviceimpl.*(..)) 

with:

execution(public * com.mycompany.myservice.MyService+.*(..)) 

The plus sign is used if you want a joinpoint to match the MyService class or a class that extends it.

I hope it helps!