RFR: 8225763: Inflater and Deflater should implement AutoCloseable [v4]

[Roger Riggs]

On Thu, 7 Nov 2024 14:16:36 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Can I please get a review of this enhancement which proposes to enhance `java.util.zip.Deflater/Inflater` classes to now implement `AutoCloseable`?
>> 
>> The actual work for this was done a few years back when we discussed the proposed approaches and then I raised a RFR. At that time I couldn't take this to completion. The current changes in this PR involve the implementation that was discussed at that time and also have implemented the review suggestions from that time. Here are those previous discussions and reviews:
>> 
>> https://mail.openjdk.org/pipermail/core-libs-dev/2019-June/061079.html
>> https://mail.openjdk.org/pipermail/core-libs-dev/2019-July/061177.html
>> https://mail.openjdk.org/pipermail/core-libs-dev/2019-July/061229.html
>> 
>> To summarize those discussions, we had concluded that:
>> - `Deflater` and `Inflater` will implement the `AutoCloseable` interface
>> -  In the `close()` implementation we will invoke the `end()` method (`end()` can be potentially overridden by subclasses).
>> - `close()` will be specified and implemented to be idempotent. Calling `close()` a second time or more will be a no-op.
>> - Calling `end()` and then `close()`, although uncommon, will also support idempotency and that `close()` call will be a no-op.
>> - However, calling `close()` and then `end()` will not guarantee idempotency and depending on the implementing subclass, the `end()` may throw an exception.
>> 
>> New tests have been included as part of these changes and they continue to pass along with existing tests in tier1, tier2 and tier3. When I had originally added these new tests, I hadn't used junit. I can convert them to junit if that's preferable.
>> 
>> I'll file a CSR shortly.
>
> Jaikiran Pai has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains nine additional commits since the last revision:
> 
>  - update tests to match the new specification
>  - Stuart's review - update the close() and end() expectations
>  - Stuart's review - improve class level javadoc
>  - merge latest from master branch
>  - merge latest from master branch
>  - Chen's suggestion - improve code comment
>  - convert the tests to junit
>  - fix whitespace
>  - 8225763: Inflater and Deflater should implement AutoCloseable

src/java.base/share/classes/java/util/zip/Deflater.java line 902:

> 900:      */
> 901:     @Override
> 902:     public void close() {

Can/should this method be final?  The real/original cleanup method is `end` and if both `close()` and `end()` are overriddable, there may be some confusion about which to implement.

src/java.base/share/classes/java/util/zip/Inflater.java line 719:

> 717:      */
> 718:     @Override
> 719:     public void close() {

Ditto, should this be `final` to be clear about what should be overridden to perform cleanup.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19675#discussion_r1832777080
PR Review Comment: https://git.openjdk.org/jdk/pull/19675#discussion_r1832787363