JavaFX Reactive Bindings and State

JavaFX Reactive Bindings and State

Use this skill when core JavaFX properties are not enough and the application needs derived observable graphs, composed event streams, reducer-style state, or synchronized reactive pipelines.

Example

import javafx.beans.binding.Bindings;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.collections.FXCollections;
import javafx.collections.transformation.FilteredList;
import javafx.scene.control.ListView;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;

public class ReactiveFilterView extends VBox {

    private final StringProperty filter = new SimpleStringProperty("");

    public ReactiveFilterView() {
        var input = new TextField();
        var items = FXCollections.observableArrayList("alpha", "beta", "gamma", "delta");
        var filtered = new FilteredList<>(items, item -> true);

        filter.bind(input.textProperty());
        filter.addListener((obs, oldValue, newValue) ->
                filtered.setPredicate(item -> item.contains(newValue))
        );

        var status = new TextField();
        status.textProperty().bind(Bindings.size(filtered).asString("Matches: %d"));
        status.setEditable(false);

        getChildren().addAll(input, status, new ListView<>(filtered));
    }
}