Headless glass platform

[Craig Raw]

Thanks Johan.

I have tested this change with a jpackaged application, and the issue no
longer appears. Platform.exit() now exits the application properly.

Craig

On Wed, Apr 10, 2024 at 1:45 PM Johan Vos <johan.vos at gluonhq.com> wrote:

> Hi Craig,
>
> Thanks for testing and for the feedback. Based on that feedback, I pushed
> a change so that the HeadlessApplication now responds properly to a
> `Platform.exit()` call (see
> https://github.com/openjdk/jfx-sandbox/commit/5c8bcb2ca1f7a72f34c3e53e209b818abf8f8504
> ).
> My implementation does a gentle stop of the processing thread, and already
> submitted runnables will be handled before the processing halts. I think
> this is how it should be, and it works with a simple application, but I
> didn't test it with a jpackaged application yet. It would be great if you
> can confirm that this is now fixed?
>
> Thanks again for the feedback!
>
> - Johan
>
> On Tue, Apr 9, 2024 at 11:37 AM Craig Raw <craigraw at gmail.com> wrote:
>
>> Hi Johan,
>>
>> As you advised in another thread, I've tested the headless glass platform
>> and find it to be an excellent solution. My particular use case is to
>> provide an alternative terminal interface (using Lanterna) for a JavaFX
>> application without needing to rewrite a great deal of the logic. For this
>> purpose, the headless glass platform works very well as a replacement to
>> Monocle.
>>
>> I encountered only one problem - calling Platform.exit() did not
>> terminate the application after it had been packaged with jpackage. This
>> did not occur with the same code using the JavaFX18 Monocle libraries on
>> Linux amd64. The JavaFX application thread was the only non-daemon thread
>> at this point. I solved this fairly simply by calling System.exit(0) after
>> Platform.exit().
>>
>> As an aside, I was impressed by how simple it was to build JavaFX. I was
>> surprised though that javafx.graphics.jar did not contain the native
>> libraries, and I had to repackage the jar to include them manually. There
>> are probably good reasons for this, but it wasn't obvious.
>>
>> It would be really good to see the headless glass platform merged into
>> JavaFX proper, and would allow me to move beyond JavaFX 18, the last
>> version to have Monocle support for Linux amd64.
>>
>> Craig
>>
>> On Fri, Feb 2, 2024 at 10:50 AM Marius Hanl <mariushanl at web.de> wrote:
>>
>>> I agree that this a nice feature, especially for headless tests as you
>>> also mentioned.
>>> Really looking forward to this feature.
>>>
>>> - Marius
>>>
>>> *Gesendet:* Dienstag, 30. Januar 2024 um 12:46 Uhr
>>> *Von:* "Johan Vos" <johan.vos at gluonhq.com>
>>> *An:* "openjfx-dev" <openjfx-dev at openjdk.org>
>>> *Betreff:* Headless glass platform
>>> Hi,
>>>
>>> I created a branch in the jfx-sandbox repository for experimenting with
>>> a headless glass platform:
>>> https://github.com/openjdk/jfx-sandbox/tree/johanvos-headless
>>>
>>> This addresses https://bugs.openjdk.org/browse/JDK-8324941 where I
>>> suggest a POC for a Headless platform.
>>>
>>> There are a number of usecases for this, including:
>>> 1. applications that require JavaFX rendering without presenting this to
>>> a window (and instead send it to a printer for example)
>>> 2. running tests without requiring a window manager.
>>>
>>> Regarding the second usecase, we already did some basic experiments
>>> using a modified version of TestFX where instead of the Monocle Headless
>>> subplatform, the POC Headless platform is used.
>>>
>>> By using a first-class Headless glass platform instead of a Monocle
>>> subplatform, it should be easier to use by developers.
>>> The monocle code contains very platform/os specific parts, which often
>>> don't make sense outside the target platform. This is very valuable, but it
>>> is also a very different usecase than a headless platform and it requires a
>>> much more complex build procedure.
>>>
>>> I added an initial, limited HeadlessRobot to do some basic tests. That
>>> code is mainly taken from the existing Monocle implementation, but I want
>>> to be careful to avoid anything that is not applicable to the headless
>>> scenarios.
>>>
>>> - Johan
>>>
>>>
>>
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