Method references with types [Re: lambda syntax tutorial]

[Rémi Forax]

Le 06/08/2010 17:40, Paul Benedict a écrit :
> Remi,
>
> That's pretty cool!! Does supporting a conversion to java.lang.reflect 
> types make a difference? I still think so because it's part of the 
> public api, but what are your thoughts on it?

There are lot of mismatches between method reference and 
java.lang.reflect.Method:

java.lang.reflect.Method is a method that is not bound to a peculiar 
receiver,
foo#bar() is a method reference which is bound to a receiver (foo).

java.lang.reflect.Method represent a callee, a method that can be called,
foo#bar() is a method reference, a call partially resolved.
(e.g. foo#bar.getAnnotation() has no meaning).

java.lang.reflect.Method checks security at each invocation,
foo#bar checks security once when created.

I let you draw your own conclusion :)

>
> Paul

Rémi

>
> On Fri, Aug 6, 2010 at 10:38 AM, Rémi Forax <forax at univ-mlv.fr 
> <mailto:forax at univ-mlv.fr>> wrote:
>
>     Le 05/08/2010 23:59, Paul Benedict a écrit :
>>     On Thu, Aug 5, 2010 at 4:58 PM, Rémi Forax <forax at univ-mlv.fr
>>     <mailto:forax at univ-mlv.fr>> wrote:
>>
>>         In fact, it will be something like
>>
>>         java.dyn.MethodHandle mh = String#length();
>>
>>
>>     Okay, so I would add that too and allow three conversions. I
>>     don't think casting to reflected methods/fields should be
>>     forgotten. I understand why JSR-292 wants to MethodHandles --
>>     that makes sense and I support it. But there is so much code
>>     today built around reflection, and being able to cast to those
>>     classes would be added value.
>>
>>     // automatic SAM conversion
>>     Arrays.sortBy(strings, String#length());
>>
>>     // automatic reflected method conversion
>>     java.lang.reflect.Method m = String#length();
>>
>>     // automatic invokedynamic conversion
>>     java.dyn.MethodHandle mh = String#length();
>>
>>     Paul
>
>     Paul,
>     there is a secret plan to rewrite java.lang.Method and java.lang.Field
>     using MethodHandle to do the plumbing.
>     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6824466
>
>     Rémi
>
>