On Tue, 4 Mar 2025 16:27:05 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> unrelated, but I would rather disallow background access to any platform >> properties. >> >> _per the earlier email_, this might (read: will) create concurrent access >> when the node is not yet attached to the scene graph: >> >> >> background thread fx app thread >> 1. start creating the node >> 2. add listener to platform prop >> 3. keep initializing the node <-- platform property change >> notification >> 4. some more code >> >> >> step 3 is when concurrent access occurs. > > There is an even more fundamental problem: JavaFX properties are not > thread-safe. You cannot safely add a listener or binding to a property in one > thread while another thread modifies that property's value. > > So I think that deferring the binding to > `Platform::accessibilityActiveProperty` is the only viable approach.There > might still be an opportunity to simplify it a bit along the lines of what > John mentions, as long as the code that binds to the property is guaranteed > to be run on the FX application thread. > > We can be certain that setting the window property to a non-null value only > happens on the FX app thread (`Stage::setScene` enforces that threading > constraint). @kevinrushforth I don't know, I would think it should be possible to create a property or property wrapper to make it thread-safe. Just having a version with all its methods synchronized is probably sufficient. If that saves a lot of complex logic in, what looks like, dozens of controls, then it seems like a far better solution to me. Of course, that should only apply to special properties; I'm not suggesting making all properties synchronized -- although I think we could as, without contention (since they're supposed to be used from a single thread), it would be nearly free, and it would make all kinds of undefined behavior scenario's when used from multiple threads (by accident or otherwise) suddenly deterministic and debuggable. ------------- PR Review Comment: https://git.openjdk.org/jfx/pull/1697#discussion_r1980107096
