views:

74

answers:

2

I have a service interface with many methods, all of which take a Request object and return a Response object. All request objects have a common ancestor and all response objects have a different common ancestor (which has a success flag and a message field).

Now I want to have an around aspect that checks permissions etc, performs the service call and returns a Response object with a failure code if anything fails. The problem is: I need to know what type of Response object to create. Is there a pointcut expression that gives me access to the return type? Something like this, perhaps?

@Around(value = "execution(public *"
    + " com.mycompany.MyService+.*(..))"
    + " && args(request)"
    + " && returning( returnType)" // something like this would be nice

, argNames = "request,returnType")
public Object handleServiceCall(final ProceedingJoinPoint pjp,
    final Request request,
    final Class<? extends Response> returnType){ ... }
A: 

You can do that check inside the around advice method(handleServiceCall() in your case)

Object actuals = pjp.proceed();
if(actuals instanceof MyResponse){
//TO:DO: Your code here
}
chedine
I know, but that won't help, because I won't always do pjp.proceed(). If my aspect decides that the user doesn't have the right to execute the service call, it will create a response object directly without proceeding.
seanizer
Do not use '*' as the 'ret-type-pattern' in the pointcut expression. Instead use the actual return type of the method that you want to intercept.
chedine
no good: I want to intercept many different return types, and I want to know which one I have.
seanizer
+2  A: 

The Javadoc for JoinPoint mentions a getSignature() method, whose return type Signature has a sub interface MethodSignature you could try casting to, which has a method getReturnType(), which might be what you are looking for.

Christian Semrau
I am aware of this. this is the way I am prepared to go if no better solution exists, but I would prefer a pointcut expression.
seanizer