On Wed, 9 Sep 2026 18:45:22 GMT, Marius Hanl <[email protected]> wrote:
>> This PR is an optimization for `Node.styleClass` and `Parent.stylesheets`. >> Instead of always initializing both properties with an empty list, we are >> creating (therefore allocating) the list on the first access instead. >> Similar to many other lazy properties. >> >> Why? >> - `Parent.getStylesheets()` is very rarely used by developers and JavaFX >> code. So this list is very often completely unused and empty. Most >> developers usually only add stylesheets at the `Scene` >> - `Node.getStyleClass()` is usually not used (empty) for layout containers >> such as `Pane` or `Group` or shapes. A JavaFX App usually consists of a good >> amount of such containers (or shapes) >> >> So that our CSS code is not initializing both lists on access, I added >> related `NodeHelper` and `ParentHelper` methods to return `null` when both >> lists were not initialized and therefore used. Otherwise we return the list >> as before. >> This will save us some memory and allocation, which is both good for the >> memory consumption but also for `Node` / `Parent` creation (time). >> >> Added documentation and tests. Will do some measurements with some apps very >> soon and attach it here. >> >> --- >> >> # Benchmarks >> >> I wrote a very small scene graph analyzer snippet to measure the memory gain. >> Feel free to test this on your own apps! >> 1. Get the `SceneGraphAnalyzer` here: >> [SceneGraphAnalyzer](https://gist.github.com/Maran23/38beca5b043e547e1a84749e3162c0b2) >> 2. Add this code to your `Scene` and press the shortcut `F12` when all of >> the UI is loaded: >> >> scene.setOnKeyPressed(event -> { >> if (event.getCode() == KeyCode.F12) { >> var analyzer = new SceneGraphAnalyzer(); >> var res = analyzer.analyze(scene); >> res.print(); >> } >> }); >> >> 3. If you have a modular app, add the following VM argument: `--add-opens >> javafx.graphics/javafx.scene=yourapp` >> >> ## Projects >> >> 1. Tested with >> [JFXCentral](https://github.com/dlsc-software-consulting-gmbh/jfxcentral2) >> >> >> +---------------------------------------------------------------+ >> | Scene Graph Analysis | >> +---------------------------------------------------------------+ >> | Nodes: 654 total, 388 parents, 266 leaves | >> +---------------------------------------------------------------+ >> | Field Null Total % N/A Avg Saved | >> | ------------------------------------------... > > Marius Hanl has updated the pull request incrementally with one additional > commit since the last revision: > > formatting and test changes modules/javafx.controls/src/main/java/com/sun/javafx/scene/control/behavior/TwoLevelFocusListBehavior.java line 195: > 193: Parent p = tlNode.getParent(); > 194: if (p != null) { > 195: if (p.getStyleClass().size() == 1 && > p.getStyleClass().contains(Properties.COMBO_BOX_STYLE_CLASS)) { This seems very strange. We detect a combo box here, but not if it has another (possibly unrelated) style class. ------------- PR Review Comment: https://git.openjdk.org/jfx/pull/2191#discussion_r4084049725
