RFR: 8294982: Implementation of Classfile API [v12]

[Maurizio Cimadamore]

On Tue, 7 Feb 2023 12:23:05 GMT, Adam Sotona <asotona at openjdk.org> wrote:

>> Uhm - I can't see these usages... something seems to be off with my IDE configuration. I did a grep and I now saw the uses. That said, having the Kind/Location inside AttributedElement still looks weird to me. The "places where an attribute can appear" is a property of an `Attribute`, not of an attributed element (which is used to model elements which can have attributes).
>
> `AttributedElement::attributedElementKind` identifies the one kind of the attributes holder.
> The "places where an attribute can appear" is available through `AttributeMapper::whereApplicable` and matched against `AttributedElement::attributedElementKind`.
> We may consider to hide or remove this auxiliary method, as `AttributedElement::attributedElementKind` might be computed from the ClassfileElement instance type.

Still, there seems to be a modelling issue here. The property of "where could this attribute go" is a property of the attribute. Of course, for usability reason, an AttributedElement might expose a predicate saying "I only accept attributes of these kinds". But it seems to me as if the API has this relationship backwards, due to _where_ the Kind interface is being defined. I think if `Kind` was defined in `AttributeMapper` it would be a tad easier to understand. And, perhaps, the `attributedElementKind` name should be changed to something like `applicableAttributeKinds` or something like that.

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PR: https://git.openjdk.org/jdk/pull/10982