RFR: 8066583: DeflaterInput/OutputStream and InflaterInput/OutputStream should explain responsibility for freeing resources [v5]

[Chen Liang]

On Thu, 20 Mar 2025 12:38:00 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Can I please get a review of this doc-only change which proposes to improve the API documentation of `DeflaterInputStream`, `DeflaterOutputStream`, `InflaterInputStream` and `InflaterOutputStream` classes?
>> 
>> As noted in https://bugs.openjdk.org/browse/JDK-8066583 some of the constructors of these classes allow callers to pass a `Deflater`/`Inflater` instance. The implementation of these classes do not close the given `Deflater`/`Inflater` when the corresponding instance of the class itself is closed. This isn't documented and can lead to situations where callers aren't aware that they are responsible for closing the given `Deflater`/`Inflater` instance. That can then lead to resource leaks of resources held by the `Deflater`/`Inflater`.
>> 
>> The commit in this PR updates the relevant constructors of these classes to add an `@implSpec` explaining the responsibility of closing the given `Inflater`/`Deflater`. I chose the `@implSpec` since each of these classes whose documentation is being updated are `public` and can be sub-classed and the `close()` method overridden. The text being added merely specifies the implementation of these classes and not the sub-classes.
>> 
>> I'll draft a CSR once we agree on the proposed text.
>
> 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:
> 
>  - merge latest from master branch
>  - additional updates to the doc
>  - merge latest from master branch
>  - change "@implSpec" to "@apiNote" and update their text
>  - add class level documentation
>  - merge latest from master branch
>  - add tests
>  - update DeflaterInputStream and InflaterInputStream
>  - 8066583: DeflaterOutputStream and InflaterOutputStream should explain responsibility for freeing resources

On second thought,

> it is the responsibility of the caller to close the Deflater as and when appropriate, after the DeflaterInputStream has been closed.

sounds a bit dubious. What if a user wishes to reuse a Deflater for another stream? 

I think wording like "[if a compressor is specified,] the compressor must remain open until the DeflaterInputStream is closed" which implies that compressors can be reused, and its closing is not coupled with the stream.

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PR Comment: https://git.openjdk.org/jdk/pull/23655#issuecomment-2746612689