RFR: 8267140: Support closing the HttpClient by making it auto-closable [v3]

[Michael McMahon]

On Tue, 14 Mar 2023 19:46:07 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> Please find here an RFE that makes the `java.net.HttpClient` auto-closeable.
>> 
>> The API has been modeled on `ExecutorService`.
>> 
>> HttpClient::close() is a graceful shutdown and will wait until all operations are terminated before returning.
>> If a request is in progress, and the caller doesn't pull the corresponding data (for instance, the request was sent with a BodyHandler.ofInputStream(), but the caller stopped reading the input stream) then close() may never return.
>> 
>> Therefore, additional methods similar to those present in `ExecutorService` are also proposed. In summary:
>> 
>> - `shutdown()`: initiate a graceful shutdown, but doesn't wait for termination. 
>> - `shutdownNow()`:  initiate an immediate shutdown, attempting to cancel all operations in progress. Doesn't wait for termination.
>> - `awaitTermination(Duration)`: await for termination within the given delay
>> - `isTerminated()` tells whether the client is terminated
>> 
>> New tests have been added to test the proposed behaviors.
>> 
>> HttpClient tests (new and old) are still stable.
>
> Daniel Fuchs has updated the pull request incrementally with one additional commit since the last revision:
> 
>   typo

src/java.net.http/share/classes/java/net/http/HttpClient.java line 816:

> 814:      * @since 21
> 815:      */
> 816:     public void shutdownNow() {

The first sentence of the `shutdownNow` api doc should describe the behavior of the method itself, ie that it does an immediate shutdown.

Also, I wonder if there is another way to formulate these implSpec comments? Naive readers might think they have to override the method.

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PR: https://git.openjdk.org/jdk/pull/13019