Updated JEP: nestmates

forax at univ-mlv.fr forax at univ-mlv.fr
Fri Apr 14 22:28:09 UTC 2017

> De: "John Rose" <john.r.rose at oracle.com>
> À: "Rémi Forax" <forax at univ-mlv.fr>
> Cc: "David Holmes" <david.holmes at oracle.com>, "Brian Goetz"
> <brian.goetz at oracle.com>, valhalla-dev at openjdk.java.net
> Envoyé: Vendredi 14 Avril 2017 22:26:37
> Objet: Re: Updated JEP: nestmates

> On Apr 13, 2017, at 3:05 PM, forax at univ-mlv.fr wrote:

>> It seems we are all on the same page but some of us talk about the spec and
>> other about the implementation.

>> From the spec point of view, i agree with Brian,
>> "Every class belongs to exactly one nest",
>> - if there is a MemberOfNest attribute, it defines the nest,
>> - if there is a NestMembers attribute, it defines the nest-top,
>> - if there is no attribute, it defines its own nest.
>> and "Every nest has a canonical, consistent nest-top".

> Confirmed. So the attributes are precursor relations which
> should not be confused with the final product entity, a nest.

> By "implementation" you mean the same thing as I mean
> when I say "precursor relations".

yes ! 

> (The product entity can be represented unambiguously
> by a Class, the nest-top of the nest. This is what leads
> to confusion, because that's not exactly the same thing
> as the class which contains the NestMembers attribute,
> nor does it *ever* contain the MemberOfNest attribute,
> despite being a member of the nest of which it is the top,
> nor is it *ever* in the NestMembers list, despite being
> a member of that same nest.)

> This tricky language is another reason to settle on a reflective
> API sooner rather than later, so we have a rigorous notation
> for this stuff. Should it be the precursors or the emergent
> Nest entity? If the latter, should there be a Class.Nest
> type or should we take a gamble and use a Class object
> to represent the Nest of which it is the nest-top?

The "precursor relation" is class based, so it's not a gamble to use the java.lang.Class object, the nest-top, to represent a nest in the reflection API. 

> — John


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