RFR: 8300517: Refactor VisibleMemberTable (method members)

[Pavel Rappo]

On Tue, 7 Mar 2023 23:48:07 GMT, Jonathan Gibbons <jjg at openjdk.org> wrote:

>> Please review this explorative refactoring for VisibleMemberTable (VMT).
>> 
>> This is the first round of refactoring for VMT. This round is about *method members*: declared (overriding and not) and inherited.
>> 
>> During this work I gained some insight into internal workings of VMT, fixed what was feasible and left TODOs and FIXMEs for everything else. Leaving those comments might look untidy, but leaving them out is wasteful: they clearly mark issues that should be revisited in upcoming rounds of refactoring.
>> 
>> As I see it today, the main issue with VMT is that implements complex and error-prone computations from Java Language Specification (JLS) by hand. For example, VMT interprets JLS rules for relations such as _inherits_, _overrides_ and _hides_. As one would imagine, sometimes VMT does it incorrectly. It would be better to eventually re-implement VMT using `javax.lang.model` as much as possible. Unlike that of `jdk.javadoc`, the day job of `javax.lang.model` is to provide JLS services.
>
> src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/Utils.java line 649:
> 
>> 647:             assert te.getKind().isClass();
>> 648:             VisibleMemberTable vmt = configuration.getVisibleMemberTable(te);
>> 649:             for (Element e : vmt.getMembers(VisibleMemberTable.Kind.METHODS)) {
> 
> In similar situations, I have found it useful to pass in a type token that determines the result type and which avoids casting the returned objects:
> 
> For example:
> 
>    <T> List<T extends Element> getMembers(VisibleMemberTable.Kind k, Class<T> clazz)

Unfortunately, there's no such thing as generic enum, which would be just the ticket here.

Type token would be okay, but perhaps only marginally better than what we have now: neither option supports static checking. Anyhow, we might revisit it in the next round of refactoring, not now.

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PR: https://git.openjdk.org/jdk/pull/12887