Name of lambda parameters

[Remi Forax]

On 01/07/2013 07:16 PM, Brian Goetz wrote:
> I think this goes into the general bucket of "you can't do reflection 
> below the method level in Java", and lambda expressions are 
> expressions and therefore below the method level.  Is lambda somehow 
> special here?

Lambda are anonymous functions, so yes, they are special. They can be 
called, have parameters, like methods so reflection should work 
otherwise you can't specify meta-protocol using lambdas and having JEE 
being able to use lambdas seems a good idea.

Rémi

>
> On 1/7/2013 1:04 PM, Remi Forax wrote:
>> (CC Alex Buckley)
>>
>> As noticed recently on lambda-dev mailing list,
>> there is no way to get the parameter names of a lambda because
>> there is no way to do reflection on a lambda (an object implementing a
>> functional interface) to get the corresponding declared method.
>>
>> do we need a static method Parameter[] Method.getLambdaParameters(Object
>> lambdaProxy) ?
>> The fact that it takes an object and not stable value (like a class,
>> etc) doesn't seem a good idea
>>
>> This may require bookkeeping when doing the functional interface
>> conversion.
>> By example, the generated lambda proxy can implement a non-public
>> interface to extract this information and for the method handle proxy,
>> it can use the internal API used by the metafactory to crack the method
>> handle.
>>
>> So, like serialization, may we need to have a special empty interface
>> NamedParameterLambda to tag these specific lambdas ? In that case, the
>> method getLambdaParameters can be a static method of 
>> NamedParameterLambda,
>> Parameter[] getLambdaParameters(NamedParameterLambda lambdaProxy).
>>
>> Rémi
>>