On Thu, 13 Feb 2025 18:41:21 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> This is only done at compilation time, not at runtime. JEP 12 elaborates on
>> this:
>>
>>> --enable-preview itself does not take a version number because it would be
>>> easy to misinterpret. For example, on JDK 18, the (hypothetical) flag
>>> --enable-preview 19 would appear to suggest support for the preview
>>> features of JDK 19, but those features are not known at the time of JDK
>>> 18's release.
>
> Yeah, that's what I came to realize as well. So our property should remain
> boolean.
>
> The only other thing I could think of is for us to provide a new utility
> method (in some class in javafx.base) that an application must call to
> register the version of JavaFX API that are compiling against. For example,
> imagine a `java.javafx.util.PreviewFeatures` class with the following method:
>
>
> public void setVersion(int featureVersion) {}
>
>
> An application would need to call `PreviewFeatures.setVersion(25)` to use
> JavaFX preview features from JavaFX 25. That method would unlock preview
> features only if the version passed in matches the runtime feature version.
> This would be in addition to the boolean system property.
>
> The question is whether it is worth the additional complexity (not for us to
> implement, that's trivial unless I'm missing something), but rather than
> documentation and burden on the app developer using a preview feature. The
> docs for each new preview feature would need to link to the PreviewFeatures
> utility class to describe how to unlock the features. On the plus side, it
> would provide a common place to document how to unlock preview features --
> "call this method from the application and set that system property on the
> command line when running the app".
I wouldn't be in favor of requiring application developers to call a method to
unlock a preview API. It seems a bit too cumbersome and intrusive to me, since
it requires you to embed build information into your source code. I've also
never seen this in other libraries or frameworks.
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PR Review Comment: https://git.openjdk.org/jfx/pull/1359#discussion_r1955264014
