RFR: 8294982: Implementation of Classfile API [v31]

[Paul Sandoz]

On Wed, 1 Mar 2023 15:00:41 GMT, Adam Sotona <asotona at openjdk.org> wrote:

>> This is root pull request with Classfile API implementation, tests and benchmarks initial drop into JDK.
>> 
>> Following pull requests consolidating JDK class files parsing, generating, and transforming ([JDK-8294957](https://bugs.openjdk.org/browse/JDK-8294957)) will chain to this one.
>> 
>> Classfile API development is tracked at:
>> https://github.com/openjdk/jdk-sandbox/tree/classfile-api-branch
>> 
>> Development branch of consolidated JDK class files parsing, generating, and transforming is at:
>> https://github.com/openjdk/jdk-sandbox/tree/classfile-api-dev-branch
>> 
>> Classfile API [JEP](https://bugs.openjdk.org/browse/JDK-8280389) and [online API documentation](https://htmlpreview.github.io/?https://raw.githubusercontent.com/openjdk/jdk-sandbox/classfile-api-javadoc-branch/doc/classfile-api/javadoc/java.base/jdk/internal/classfile/package-summary.html) is also available.
>> 
>> Please take you time to review this non-trivial JDK addition.
>> 
>> Thank you,
>> Adam
>
> Adam Sotona has updated the pull request incrementally with four additional commits since the last revision:
> 
>  - renamed all remaining ConcreteXyzEntry to XyzEntryImpl
>  - abstract implementations of RefEntry, RefsEntry and NamedEntry renamed to AbstractRefEntry, AbstractRefsEntry and AbstractNamedEntry
>  - renamed ConcreteBootstrapMethodEntry to BootstrapMethodEntryImpl
>  - ConcreteEntry renamed to AbstractPoolEntry

src/java.base/share/classes/jdk/internal/classfile/snippet-files/PackageSnippets.java line 111:

> 109:         Set<ClassDesc> dependencies = cm.elementStream()
> 110:                                         .filter(ce -> ce instanceof MethodModel)
> 111:                                         .flatMap(ce -> ((MethodModel) ce).elementStream())

You could potentially collapse this into a single `flatMap` and avoid the cast:

.flatMap(ce -> ce instanceof MethodMethod mm ? mm.elementStream() : Stream.empty())

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