JavaFX Application create traffic light

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.RadioButton;
import javafx.scene.control.ToggleGroup;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class Main extends Application {
   @Override//w w w  .j a v  a2s  . c o  m
   public void start(Stage primaryStage) {
      Pane lightPane = new Pane();
      Rectangle tLight = new Rectangle(0, 0, 100 / 3.0, 100);
      Circle redLight = new Circle(100 / 3.0 / 2, 100 / 4.0, 10);
      Circle yellowLight = new Circle(100 / 3.0 / 2, 100 / 2.0, 10);
      Circle greenLight = new Circle(100 / 3.0 / 2, 100 / 4.0 * 3, 10);
      tLight.setFill(Color.WHITE);
      tLight.setStroke(Color.BLACK);
      tLight.xProperty().bind(lightPane.widthProperty().divide(2).subtract(tLight.getWidth() / 2));
      tLight.yProperty().bind(lightPane.heightProperty().divide(2).subtract(tLight.getHeight() / 2));
      redLight.setFill(Color.WHITE);
      redLight.setStroke(Color.BLACK);
      redLight.centerXProperty().bind(lightPane.widthProperty().divide(2));
      redLight.centerYProperty().bind(tLight.yProperty().add(20));
      yellowLight.setFill(Color.WHITE);
      yellowLight.setStroke(Color.BLACK);
      yellowLight.centerXProperty().bind(lightPane.widthProperty().divide(2));
      yellowLight.centerYProperty().bind(tLight.yProperty().add(50));
      greenLight.setFill(Color.WHITE);
      greenLight.setStroke(Color.BLACK);
      greenLight.centerXProperty().bind(lightPane.widthProperty().divide(2));
      greenLight.centerYProperty().bind(tLight.yProperty().add(80));

      lightPane.getChildren().addAll(tLight, redLight, yellowLight, greenLight);

      RadioButton rbRed = new RadioButton("Red");
      RadioButton rbYellow = new RadioButton("Yellow");
      RadioButton rbGreen = new RadioButton("Green");

      ToggleGroup tg = new ToggleGroup();
      rbRed.setToggleGroup(tg);
      rbYellow.setToggleGroup(tg);
      rbGreen.setToggleGroup(tg);

      HBox controlPane = new HBox(10);
      controlPane.getChildren().addAll(rbRed, rbYellow, rbGreen);
      controlPane.setAlignment(Pos.CENTER);

      BorderPane pane = new BorderPane();
      pane.setCenter(lightPane);
      pane.setBottom(controlPane);

      rbRed.setOnAction(e -> {
         redLight.setFill(Color.RED);
         yellowLight.setFill(Color.WHITE);
         greenLight.setFill(Color.WHITE);
      });

      rbYellow.setOnAction(e -> {
         redLight.setFill(Color.WHITE);
         yellowLight.setFill(Color.YELLOW);
         greenLight.setFill(Color.WHITE);
      });

      rbGreen.setOnAction(e -> {
         redLight.setFill(Color.WHITE);
         yellowLight.setFill(Color.WHITE);
         greenLight.setFill(Color.GREEN);
      });

      Scene scene = new Scene(pane, 300, 150);
      primaryStage.setTitle("java2s.com");
      primaryStage.setScene(scene);
      primaryStage.show();
   }

   public static void main(String[] args) {
      launch(args);
   }
}