Access Modifier Issues

[Peter Levart]

On 01/09/2015 03:11 PM, Richard Warburton wrote:
> Hi gents,
>
> Not sure if its a high priority to fix the access modifier problems at the
> moment, but there still seems to be a bug with Peter Levart's default hack
> which I didn't see reported in the other thread.

Yes, Maurizio already warned about currently buggy access to private 
members from specialized methods. I think you can work-around by using 
package-private access for the time being.

>
> public class Default<any T> {
>
>      private T value;
>
>      private Default() {}
>
>      public static <any T> T value() {
>          return new Default<T>().value;
>      }
>
>      public static void main(String[] args) {
>          int i = Default.value();
>          System.out.println(i);
>          long l = Default.value();
>          System.out.println(l);
>          Object o = Default.value();
>          System.out.println(o);
>      }
>
> }
>
> When running:
>
> Specializing method Default$value${0=I}.value()Ljava/lang/Object; with
> class=[] and method=[I]
> Specializing Default${0=I}; searching for Default.class (not found)
> Specializing Default${0=I}; searching for Default.class (found)
> Exception in thread "main" java.lang.IllegalAccessError: tried to access
> method Default${0=I}.<init>()V from class Default$value${0=I}/793589513
>          at Default$value${0=I}/793589513.value(Default.java:8)
>          at Default.main(Default.java:12)
>
> Looks like its workaround-able by making both the constructor and value
> field public.
>
> I think this also exposes something I don't understand here. My impression
> was that "Default${0=I}" was the specialisation of the class Default s.t.
> its first type parameter is an int. So what is "Default$value${0=I}"?

I think Default$value${0=I}/793589513 is a special (VM-annonymous) 
class, containing the specialization of static method Default.value() 
for T=int.

The problem seems to be that private constructor of specialized class 
Default for T=int is not accessible from it. The specialized static 
method does have access to private members of nonspecialized class 
Default (since this is the host class of it's VM-anonymous class where 
it is defined), but not to the specialized Default class for T=int which 
is a separate class. Perhaps something similar to how outer class has 
access to private members of inner classes and vice-versa would have to 
be devised among non-specialized classes and their specializations.

Regards, Peter

>
> regards,
>
>    Richard Warburton
>
>    http://insightfullogic.com
>    @RichardWarburto <http://twitter.com/richardwarburto>