RFR: 8349373: Support JavaFX preview features [v2]

[Andy Goryachev]

On Tue, 4 Feb 2025 19:34:29 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> modules/javafx.base/src/main/java/com/sun/javafx/PreviewFeature.java line 37:
>> 
>>> 35:  * has opted into preview features.
>>> 36:  */
>>> 37: public enum PreviewFeature {
>> 
>> Why enum?
>> Maybe use a regular class with a public constructor should do it.
>> What do you think?
>
> The idea is to make it easy and obvious to use from preview code:
> 
> PreviewFeature.MY_PREVIEW_FEATURE.checkEnabled();
> 
> In addition to that, any IDE can easily list all uses of an enum constant, which gives you an overview where APIs of a particular feature are located. After all, enums are just regular classes with singleton instances.
> 
> By the way, preview features can't be individually enabled or disabled. The point of checking on a enum constant is to generate an appropriate error message (including the name of the feature) in case the user didn't enable preview features.

my only objection is that enum implies the use of a switch pattern, which is not really applicable here.

since it's in com.sun.* hierarchy and only intended for jfx devs, I am fine with enum.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1359#discussion_r1941790951