[aspectj-users] Re: Simplification of generic / parameterized type match

[Adrian Colyer <adrian.colyer@xxxxxxxxx>]

We considered that simplification. The problem then becomes when you
bind arguments in advice:

For example:

before(List l) : execution(String shead(List)) && args(l) {

  // here we have to work with the raw type list inside the advice body
  // and lose the nicely typed collections that Java gives us
  String s = (String) l.first();
  ... 

}

As opposed to:

before(List<String> ls) : execution(String shead(List<String>)) && args(l) {

  // now we can continue working with the typed collection...
  String s = ls.first();
}

Being unable to work with parameterized type information inside advice
felt like a bridge too far, hence support for List<String>...


On 01/08/05, Shigeru Chiba <chiba@xxxxxxxxxxxxxxx> wrote:
> Thanks for your reply.
> 
> So,
> 
> class List<T> {
>    T value;
>    List<T> next;
>    static T thead(List<T> list) { return list.value; }
>    static String shead(List<String> list) { return list.value; }
> }
> 
> The issue is that the signature of thead() is "Object thead(List)" but
> the signature of shead() is "String shead(List<String>)".  I thought
> this distinction is a bit confusing.  A extremely simple solution
> might be to use only the erasure type "List" for both List<T> and
> List<String>.
> So the signature of shead is now "String shead(List)".  This
> simplification
> would make it easy to understand AspectJ 5 although it would also be too
> simple for practice.
> 
> Best regards,
> 
> Chiba

-- 
-- Adrian
adrian.colyer@xxxxxxxxx