[aspectj-users] Question about around() advice and exception handling

["David Budworth" <dbudworth@xxxxxxxxx>]

Hello folks,

I was looking in to using AspectJ as a replacement for my current JBossAOP based aspects but I got stumped on a few things.

First was the seeming lack of perJoinPoint type constructs.  Which I resolved by making an IdentityHashMap<
JoinPoint.StaticPart,MyState> type cache whenever a new joinpoint was executed.  Works basically the same.

Second, I can't seem to figure out how to genericly wrap methods in an around type construct.
In JBossAOP it was as simple as:
@Bind("blah")
public Object adviceMethod(MethodInvocation mi) throws Throwable){
  Object ret = null;
  Object fault = null;
   ...do random stuff this advice wants to do...
   try{
     ret = mi.invokeNext();
   }
   catch(Throwable th){
       fault = th;
   }
   ...do random stuff this advice wants to do...
   if (fault) throw fault;
   return ret;
}



Problem I have in AspectJ is that it seems I must know the target methods declared checked exceptions.  Which isn't really possible.  
example:
@Tx
public void foo() {
   ... foo stuff...
}
@Tx
public void bar() throws Exception{
   ...bar stuff...
}


There seems to be no construct in AspectJ's language (not the AJ 1.5 annotations, I'm using the traditional aspectj style) to have a catch all / rethrow all type thing.

That or I'm just missing it.

I could make an around() aspect with a:

public around() : execution(@Tx * *(..)) {
   boolean failed = true;
   try{
    proceed();
    failed=false;
  }
  finally{
    if (failed) ...do bad thing (rollback / etc) ...
    else ...do good thing (commit / etc)...
  }
}


but that seems odd, plus I'd lose the ability to see how something fails. 

I don't want to use soften since it seems to mask the actual exception thrown which would break virtually all of our code (lots of JDBC / JMS stuff)

It's entirely possible that I'm missing the page with the magic syntax of something like
around() throws *? : execution(@Tx * *(..) throws *?)

Aside from my initial hurdles of syntax/convention converting from JBossAOP to AspectJ, I really like the AspectJ way of doing things.

I look forward to taking our JBossAS restart time from 3min back down to ~2min when this conversion is complete (due to limitations in jbaop's aopc we must use loadtime weaving which adds 1+min to our deploy cycle, which is why I'm trying to switch to AspectJ)