RFR: JDK-8315464: Uncouple AllClassesIndexWriter from IndexBuilder [v2]

[Jonathan Gibbons]

On Fri, 15 Sep 2023 16:04:28 GMT, Hannes Wallnöfer <hannesw at openjdk.org> wrote:

>> My original intention with this cleanup was to keep using `[Html]IndexBuilder' for both the "All Classes" and the main index, but just improve separation of code and naming of classes. However, I then discovered two things:
>> 
>>  - The "All Classes" page is so simple to build that it doesn't justify using a complex builder class. In fact, moving the necessary functionality from `IndexBuilder` to `AllClassesIndexWriter` just added about a dozen lines of code to the latter, while making `IndexBuilder` much simpler by removing its dual purpose.
>>  - The separation of code between `toolkit.util.IndexBuilder` and `formats.html.HtmlIndexBuilder`, although seemingly random at first sight, actually reflects the usage of functionality provided by the respective packages. Although with a single output format the separation between these packages is not as important as it used to be, it is still nice to keep things separated.
>> 
>> Based on these two findings, I decided to pull the "All Classes" code into "AllClassesIndexWriter", but maintain the implementation of `[Html]IndexBuilder` across the two classes/packages. Although the base `IndexBuilder` class is technically able to function on its own without the HTML-specific enhancements, I made the class abstract in order to point out that the HTML enhancements in `HtmlIndexBuilder` are actually essential for our us.
>
> Hannes Wallnöfer has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AllClassesIndexWriter.java
>   
>   Remove whitespace
>   
>   Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>

Approved.

I assume all tests pass, and that JDK API docs are not affected.

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Marked as reviewed by jjg (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15746#pullrequestreview-1640390416