RFR: 8252374: Add a new factory method to concatenate a sequence of BodyPublisher instances into a single publisher. [v4]

[Chris Hegarty]

On Fri, 18 Sep 2020 09:01:56 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> Continuing the review with a PR...
>> 
>> 8252374: Add a new factory method to concatenate a sequence
>>          of BodyPublisher instances into a single publisher.
>> https://bugs.openjdk.java.net/browse/JDK-8252374
>> 
>> 
>> Draft CSR:
>> https://bugs.openjdk.java.net/browse/JDK-8252382
>
> Daniel Fuchs 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 four additional commits since
> the last revision:
>  - Merge remote-tracking branch 'origin/master' into concat-bs-8252374
>  - Merge remote-tracking branch 'origin/master' into concat-bs-8252374
>  - Merge remote-tracking branch 'origin/master' into concat-bs-8252374
>  - 8252374: Add a new factory method to concatenate a sequence of BodyPublisher instances into a single publisher.

src/java.net.http/share/classes/java/net/http/HttpRequest.java line 668:

> 666:          * is returned. Otherwise each publisher is lazily subscribed to in turn,
> 667:          * until all the body bytes are published, an error occurs, or the
> 668:          * returned publisher's subscription is cancelled.

We should probably say what the publishers `contentLength` will return.

src/java.net.http/share/classes/java/net/http/HttpRequest.java line 661:

> 659:
> 660:         /**
> 661:          * Creates a {@code BodyPublisher} that publishes a request

Trivially, should we replace "Creates" with "Returns" to allow for the possibility of, say, a singleton empty publisher
(rather than having to "create" a new empty each time)

src/java.net.http/share/classes/java/net/http/HttpRequest.java line 680:

> 678:          * cancelled}, or an error occurs while publishing the bytes, not all
> 679:          * publishers in the sequence may be subscribed to.
> 680:          * A publisher may be subscribed several times in sequence if the

I think that this sentence can be moved out of the implNote and into normative text

src/java.net.http/share/classes/java/net/http/HttpRequest.java line 688:

> 686:          * by each publisher in the sequence.
> 687:          */
> 688:         public static BodyPublisher concat(BodyPublisher... publishers) {

It's a choice whether to allow an empty publishers array, or an array of just 1, or to disallow (throw
IllegalArgumentException), but that will depend on expected usage.

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PR: https://git.openjdk.java.net/jdk/pull/57