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Re: [aspectj-users] How to test complex pointcut patterns? 
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maly.velky@xxxxxxxx schrieb:
> What do you use for getting your pointcut patterns right?

Hi Jakub,

indeed, using AspectJ now since several years, I've found there is the
possibility to get astray. Some of my observations/guidelines:

- - the moment you're going to target individual methods or (worse) specific
  parameter patterns, you should be alarmed.
  Such tends to be unstable and cause endless maintenance problems.

- - try fist to create specific interfaces, which capture a concept precisely.
  And then write your pointcuts against those interfaces.

- - use annotations instead of method/class names to direct the match

- - try to be *declarative*
  That means: a set of pointcuts should describe a *logical* relationship,
  and *not* a specific execution situation.

- - and by all means: *name* your pointcuts!
  Never create such a "train wreck" sequence of && and || with dozens of
  individual patterns. Instead, create small logical groups (1..3 clauses)
  and *try to give them a descriptive and precise name*
  Naming is not just avoidable bla bla. It's the key of getting things right.
  If you aren't able to give a pointcut a proper name, you should consider
  it broken!

If you adhere to this rules, testing is rather simple. Write a test/dummy
before advice for each separately named pointcut, and verify (either with
the AJDT cross reference view or by log messages) that it matches the
right targets.

Regarding the example you quoted, I'd propose the following:

> (portletEntryMethods() AND !cflowbelow(portletEntryMethods()))
> || (call(* javax.xml.soap.SOAPConnection.call(..))
>    AND within(com.tonbeller.jpivot.xmla.XMLA_SOAP))
> || (within(com.tonbeller..*)
>    AND (execution(* XMLA_SOAP.discover(..))
> || execution....

- - the final "top level" pointcut, which you are addressing in your advice
  should be just a disjunction of named pointcuts
- - the parts in turn should be the conjugation of named sub-pointcuts
- - the within() pointcuts should be declared abstract and the specific
  packages pushed down into the concrete aspect.
- - you can use *one* aspect just to place annotations on specific methods;
  which then can be targeted by other aspects!
  Couldn't you utilise this technique to simplify your pointcut? for example
  all the various execution pointcuts could be replaced by a pointcut targeting
  the execution of a method with a custom annotation. And another aspect would
  place this annotation at the right places.

Hope this helps
Cheers,
Hermann Vosseler



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