On Thu, 31 Aug 2023 06:59:29 GMT, David Holmes <dhol...@openjdk.org> wrote:
>> Sorry, my description in Issue JDK-8314194(which I submitted) is ambiguous
>> and makes you think of Phaser. My intention is that each generation of
>> CyclicBarrier barrierCommand can change. Let me give you a scenario
>> For example, the U.S. Army 'Gordon Sullivan Cup'.
>> Five tanks competing.
>> 1. The first round is for artillery strikes against targets.
>> 2. Second round of anti-aircraft machine gun targets.
>> 3. The third round is minefield racing.
>> The scoring criteria are different for each round, so the CyclicBarrier's
>> barrierCommand should be different for each round. But in the current code,
>> `private final Runnable barrierCommand`, constructing the CyclicBarrier
>> instance is already determined to be unchangeable.
>
> As I wrote in the JBS issue and as Alan mentioned again above you can use the
> single `BarrierAction` object to track the state changes and count the
> generations/phase:
>
> Runnable barrierAction = new Runnable() {
> int phase = 0;
> public void run() {
> switch(phase++) {
> case 0: doArtillery(); break;
> case 1: doAntiAircraft(); nreak;
> case 2: doMinefield(); break;
> }
> void doArtillery() { ... }
> ...
> }
>
> I do not believe there is sufficient justification for expanding the
> `CyclicBarrier` API as proposed.
>
> Happy to hear what @DougLea and @martin-buchholz think about this though.
I agree with @dholmes-ora — the transition is in/belongs to the action, not the
barrier.
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PR Comment: https://git.openjdk.org/jdk/pull/15239#issuecomment-1700503736
