On Tue, 25 Feb 2025 22:33:40 GMT, Andy Goryachev <ango...@openjdk.org> wrote:
>> Root Cause: >> (Multiple) properties are getting bound to the global >> `Platform.accessibilityActive` property. Binding (and I say, accessing) of >> properties is not thread-safe. >> >> I also changed the design a bit. Originally, every symbol in a chart had >> its `focusTraversableProperty` bound to `Platform.accessibilityActive` in >> order to enable the accessibility navigation across the chart data points. >> This is rather inefficient, as the property has to manage (thousands?) of >> listeners. >> >> Instead, a single boolean property is added to each chart, with a listener >> added to it which iterates over data symbols to toggle the >> `focusTraversableProperty` directly. >> >> The exact moment when the new property gets bound is also important, and has >> to happen in the FX application thread. >> >> With this change, it is safe to create and populate charts with data in a >> background thread. >> >> --- >> >> ## NOTES >> >> 1. It looks like the `Platform.accessibilityActive` property never >> transitions back to false after it transitioned to true. Some say it is >> because there is no mechanism in the platform to get notified which cannot >> possibly be true. >> 2. The javadoc for `Platform.accessibilityActiveProperty()` method >> stipulates that "_This method may be called from any thread_" which is >> patently not true as the current implementation is simply not thread-safe. >> >> ## Note to the Reviewers >> >> To avoid merge conflicts, the preferred order of integrations: >> >> #1697 >> #1713 >> #1717 > > Andy Goryachev has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 25 commits: > > - Merge remote-tracking branch 'origin/master' into > 8349091.charts.thread.safety > - review comments > - Merge remote-tracking branch 'origin/master' into > 8349091.charts.thread.safety > - Merge remote-tracking branch 'origin/master' into > 8349091.charts.thread.safety > - enabled pie chart test > - Merge branch 'master' into 8349091.charts.thread.safety > - Merge branch 'master' into 8349091.charts.thread.safety > - whitespace > - Merge remote-tracking branch 'origin/master' into > 8349091.charts.thread.safety > - cleanup > - ... and 15 more: https://git.openjdk.org/jfx/compare/7a7854c9...4288d1d0 modules/javafx.controls/src/main/java/javafx/scene/chart/Chart.java line 550: > 548: handleAccessibilityActive(on); > 549: }); > 550: return active.get(); I'm confused as to what is happening here. A boolean property `active` is created, which is bound to `Platform.accessibilityActiveProperty` (this creates a listener on `accessibilityActiveProperty`). We add then another listener on `active`. What confuses me is what this is supposed to achieve, and also why we're initialising the property, but then bind it anyway... `active = new SimpleBooleanProperty(aa)` and later `active.bind` means that the variable `aa` is completely unnecessary as the `bind` will do this `get` for you. ------------- PR Review Comment: https://git.openjdk.org/jfx/pull/1697#discussion_r1978258927
