RFR: 8267546: Add CSS themes as a first-class concept [v2]

[Michael Strauß]

On Fri, 11 Nov 2022 01:11:36 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> modules/javafx.graphics/src/main/java/javafx/application/PlatformPreferences.java line 117:
>> 
>>> 115:  * @since 20
>>> 116:  */
>>> 117: public interface PlatformPreferences extends Map<String, Object> {
>> 
>> Are you sure it is a good idea to expose these as a `Map`?  It seems to me that this isn't that good a practice any more to have classes implement or extend lists/maps/sets as they pull in a huge amount of API surface that is mostly useless or too general for the class's purpose.
>> 
>> The addition of the listener management methods also has me wondering, as `ObservableMap` does something similar.
>
> All of the mutating methods are useless, since the implementation always returns a read-only map. However, the alternative would be to duplicate APIs to enumerate and inspect the contents of the `PlatformPreferences` map (applications might want to show a list of available preferences). I'm not sure that's preferable, mostly because `PlatformPreferences` _does_ represent a mapping of keys to values.
> 
> It's true that listener management makes it look like an `ObservableMap`. The difference is that `ObservableMap` doesn't support batch change notifications, which the current implementation relies on to minimize the number of style theme resets. Of course, that could be solved in a different way.

> The addition of the listener management methods also has me wondering, as `ObservableMap` does something similar.

I've switched to using `ObservableMap`.

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PR: https://git.openjdk.org/jfx/pull/511