On Fri, 3 Jul 2026 09:16:00 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 ║ >> ╠══════════════════════════════════════════════════╣ >> ║ Total nodes: 654 ║ >> ║ ├─ Parent nodes: 388 ║ >> ║ └─ Leaf nodes: 266 ║ >> ╠══════════════════════════════════════════════════╣ >> ║ Null styleClass: 19 / 654 ( 2.9%) ║ >> ║ Null stylesheets: 3... > > Marius Hanl has updated the pull request incrementally with one additional > commit since the last revision: > > review comments It doesn't look like this will be ready before the jfx27 RDP1 fork, but in the unlikely event that it is, wait until after the fork. Any CSS lazy eval fix has a relatively high risk of regression, so this is the sort of change that is better earlier in the release cycle. ------------- PR Comment: https://git.openjdk.org/jfx/pull/2191#issuecomment-4981233903
