Javafx: How to hide XYChart Node when binding == null - javafx

Question

I am binding a linechart to several TextFields, which contain double values as strings, or are empty. It works fine if the Field contains a number, but unfortunatey, I get an exception when it is empty.
I could find a way to handle "emptyness" and set it to 0.0, but actually I need to hide the node completey in this case (If "X" or "Y" Field is empty)
Any ideas how to solve it?
Basic Example with only one set of Textfields:
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.scene.chart.XYChart.Data;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
public class LineChartSample extends Application {
#Override
public void start(Stage stage) {
stage.setTitle("Demo");
final NumberAxis xAxis = new NumberAxis();
final NumberAxis yAxis = new NumberAxis();
xAxis.setLabel("X");
yAxis.setLabel("Y");
final LineChart<Number, Number> lineChart = new LineChart<Number, Number>(xAxis, yAxis);
AnchorPane ap = new AnchorPane();
lineChart.setTitle("Demo");
XYChart.Series series = new XYChart.Series();
AnchorPane.setTopAnchor(lineChart, 5d);
AnchorPane.setLeftAnchor(lineChart, 5d);
AnchorPane.setRightAnchor(lineChart, 5d);
TextField t1 = new TextField("33.3");
TextField t2 = new TextField("33.3");
Data d = new XYChart.Data();
d.XValueProperty().bind(Bindings.when(t1.textProperty().isEmpty())
.then(0.0) // <-- here is the problem
.otherwise(Bindings.createDoubleBinding(() -> {
return Double.parseDouble(t1.getText());
}, t1.textProperty())));
d.YValueProperty().bind(Bindings.when(t2.textProperty().isEmpty())
.then(0.0) // <-- here is the problem
.otherwise(Bindings.createDoubleBinding(() -> {
return Double.parseDouble(t2.getText());
}, t2.textProperty())));
series.getData().add(d);
AnchorPane.setBottomAnchor(t1, 50d);
AnchorPane.setLeftAnchor(t1, 5d);
AnchorPane.setBottomAnchor(t2, 50d);
AnchorPane.setRightAnchor(t2, 5d);
ap.getChildren().addAll(lineChart, t1, t2);
Scene scene = new Scene(ap, 800, 600);
lineChart.getData().add(series);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}

Answer 1

I found a solution by adding
t1.textProperty().addListener((observable) -> {
if (t1.getText().isEmpty() || t2.getText().isEmpty()) {
d.getNode().setVisible(false);
} else {
d.getNode().setVisible(true);
}
});
t2.textProperty().addListener((observable) -> {
if (t1.getText().isEmpty() || t2.getText().isEmpty()) {
d.getNode().setVisible(false);
} else {
d.getNode().setVisible(true);
}
});
But if anybody knows a more elegant way, I would be quite happy.