Results of review of private JavaFX API for consideration to make public in JDK 9

[Jonathan Giles]

It is likely that these classes will be included as part of JEP 253 (in 
subproject 3), so they will likely become public API. Javadoc output for 
this subproject will be posted in the next week or two. Keep your eyes 
peeled :-)

-- Jonathan

On 11/08/2015 4:42 a.m., Hervé girod wrote:
> It passed under my radar that we use classes in com.sun.javafx.css, and com.sun.javafx.css.parser, mainly :
> - CSSParser
> - Stylesheet
> - Selector
> - Rule
>
> The use case is to be able to process JavaFX stylesheets properties.
>
> Hervé
>
> Sent from my iPad
>
>> On 7 août 2015, at 01:10, Jonathan Giles <jonathan.giles at oracle.com> wrote:
>>
>> Hi all. In April of this year a discussion began when news broke that with JDK 9 access to private com.sun.* APIs would be disappearing [1]. A while back I posted a request to openjfx-dev for people to send me their JDeps output so that it could be analysed and used to inform our decisions around which API we should try to promote into public API. The response was very useful (and I should note: its too late now, please don't send me anymore JDeps files), and I believe we have the beginnings of a plan on how to move forward.
>>
>> Before I outline the plan, please note that this discussion would ideally _not_ devolve into a feature requests discussion. What we are wanting to talk about today is simply API that exists in the com.sun.* package namespace which we can conceivably bring out of this namespace for JDK 9. Developing new API is expressly out of scope (unless it is related to simplifying or wrapping the com.sun.* API).
>>
>> Another important point - UI control skins and a lot of very useful CSS API are being made public under JEP 253 [2]. A lot of the skin code has already been cleaned up, simplified, documented, etc, and will be merging into a repo very soon. I'll also post a separate post about JEP 253 soon.
>>
>> So, what does my JDeps analysis show (ignoring UI Controls and CSS usage, which has been largely resolved by JEP 253)? I can sum it up in the following categories:
>>
>> == 'Toolkit' API ==
>> A lot of people use a small amount of API from Toolkit, such as the API for nested event loops, to fire a pulse, and to add / remove pulse listeners. Based on this analysis, the current thinking is to add API into the javafx.application.Platform class to enable the first two use cases above (nested event loops and pulse firing). The third use case needs more engineering effort, and is a far less common use case, so isn't being considered for JDK 9.
>>
>> == 'Traversal' API ==
>> This API lives in com.sun.javafx.scene.traversal, and is quite useful when writing custom controls to ensure that keyboard traversal puts the focus in the right node at the right time. My ControlsFX open source project is a common (ab)user of this API, so I have a vested interest in making this public. Having said this, the API is actually in quite good shape, and it is possible with just a little JavaDoc work it could make the move into javafx.scene.traversal.
>>
>> == 'Collections Event' API ==
>> There exists classes in com.sun.javafx.collections that are quite useful if you create your own custom ObservableList implementation and want to fire events at certain times. In my analysis there are only two projects using these APIs: ControlsFX and JVx by SIB Visions. The other pertinent point is that this code is quite easy to reproduce, so, whilst I would like to see this API public, it doesn't seem to make sense for JavaFX 9.
>>
>> == 'Utils' API ==
>> There exists three classes that are quite commonly used by people for the various utility methods contained within. These classes are com.sun.javafx.util.Utils, com.sun.javafx.PlatformUtil, and com.sun.javafx.application.PlatformImpl. As most of these classes are just a collection of self-contained methods, it is quite likely that a number of these methods will find public API alternatives in a new class (although there are no plans to move all the methods over!).
>>
>> == Miscellaneous API ==
>> Finally, there are a few classes that popped up quite frequently. Here is the list, and my thoughts on what to do with them:
>>
>> 1) com.sun.javafx.runtime.VersionInfo: Questionable about usefulness - not a likely candidate for JDK 9.
>> 2) com.sun.javafx.event.EventHandlerManager: Only used in ControlsFX - not a likely candidate for JDK 9.
>> 3) Robot: A good API to make public, but not a small API, so the scope is possibly too great for JDK 9.
>> 4) PerformanceTracker: Same as Robot - good, but API might require more time than is available for JDK 9.
>>
>> == What about other private API ==
>> If I've stated that an API you use isn't likely to make the cut for 9, there is another option: pull up your sleeves and work with us to get the API into a shape where it is good enough to commit to as public API. I should note that you shouldn't just dive in and do this - ping us and let us know first, so we can sync up and make sure the plan is feasible (and not overlapping). Because any large chunk of work would require moving through the JEP process, it is unlikely that anything other than small tweaks would be acceptable. One such example might be the PerformanceTracker.
>>
>> == Where to from here? ==
>> The first milestone is to get JEP 253 into the main repo. That should hopefully be done before the end of August. Once that is done, focus can shift to the areas identified in this email. In the mean time, if there is any community feedback, please get it in ASAP so it can be included in the consideration.
>>
>> [1] http://mail.openjdk.java.net/pipermail/openjfx-dev/2015-April/017017.html
>> [2] http://openjdk.java.net/jeps/253
>>
>> Thanks!
>> -- Jonathan