> 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 | > | ----------------------------------------------------------- | > | stylesheets 386 / 388 99.5% - - 39.20 KB | > ...
Marius Hanl has updated the pull request incrementally with one additional commit since the last revision: Use String.join ------------- Changes: - all: https://git.openjdk.org/jfx/pull/2191/files - new: https://git.openjdk.org/jfx/pull/2191/files/39a23432..a31e3243 Webrevs: - full: https://webrevs.openjdk.org/?repo=jfx&pr=2191&range=06 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2191&range=05-06 Stats: 12 lines in 2 files changed: 0 ins; 10 del; 2 mod Patch: https://git.openjdk.org/jfx/pull/2191.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2191/head:pull/2191 PR: https://git.openjdk.org/jfx/pull/2191
