JavaFX BorderPane extend to create custom control

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.control.RadioButton;
import javafx.scene.control.ToggleGroup;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Ellipse;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.Shape;
import javafx.scene.text.Font;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Main extends Application {

   public static void main(String[] args) {
      Application.launch(args);/*from w  w  w.  j  av a  2  s .c o  m*/
   }

   @Override
   public void start(Stage primaryStage) throws Exception {

      Text text = new Text(50, 50, "JavaFX");
      text.setFont(Font.font("Arial", 20));

      ShapePane pane = new ShapePane();

      primaryStage.setScene(new Scene(pane));
      primaryStage.setTitle("Text Pane");
      primaryStage.show();
   }

}

class ShapePane extends BorderPane {

   public ShapePane() {

      // create 3 shapes
      Shape[] shapes = new Shape[3];
      shapes[0] = new Circle(50);
      shapes[1] = new Rectangle(200, 100);
      shapes[2] = new Ellipse(45, 30);

      // Center pane that displays shapes
      StackPane centerPane = new StackPane();
      setCenter(centerPane);

      // set shapes default settings
      for (Shape s : shapes) {
         s.setFill(Color.TRANSPARENT);
         s.setStroke(Color.BLACK);
      }

      // create radio buttons
      RadioButton[] rbButtons = new RadioButton[3];
      rbButtons[0] = new RadioButton("Circle");
      rbButtons[1] = new RadioButton("MyRectangle");
      rbButtons[2] = new RadioButton("Ellipse");

      CheckBox cbFill = new CheckBox("Fill");
      cbFill.setOnAction(e -> {
         Shape shape = (Shape) centerPane.getChildren().get(0);
         if (cbFill.isSelected()) {
            shape.setFill(Color.BLACK);
         } else {
            shape.setFill(Color.TRANSPARENT);
         }
      });

      HBox bottomHbox = new HBox(10);
      bottomHbox.getChildren().addAll(rbButtons);
      bottomHbox.getChildren().add(cbFill);
      setBottom(bottomHbox);
      // bottomPane default settings
      bottomHbox.setAlignment(Pos.CENTER);
      bottomHbox.setPadding(new Insets(1, 10, 1, 10));

      ToggleGroup group = new ToggleGroup();
      for (int i = 0; i < rbButtons.length; i++) {
         final int index = i;
         rbButtons[i].setToggleGroup(group);
         rbButtons[i].setOnAction(e -> {

            if (shapes[index].getFill() != Color.TRANSPARENT) {
               cbFill.setSelected(true);
            } else {
               cbFill.setSelected(false);
            }
            centerPane.getChildren().clear();
            centerPane.getChildren().add(shapes[index]);

         });
      }
      setPrefHeight(200);

   }
}