JavaFX Circle move by key event

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class Main extends Application {
   @Override//from   w w  w.j ava2  s. c  o m
   public void start(Stage primaryStage) {
      // Create a pane
      Pane pane = new Pane();
      pane.setPadding(new Insets(20, 20, 20, 20));
      // Create a circle
      Circle circle = new Circle(20, 20, 20);
      pane.getChildren().add(circle);

      // Create and register the handle
      pane.setOnKeyPressed(e -> {
         switch (e.getCode()) {
         case UP:
            circle.setCenterY(
                  circle.getCenterY() > circle.getRadius() ? circle.getCenterY() - 10 : circle.getCenterY());
            break;
         case DOWN:
            circle.setCenterY(circle.getCenterY() < pane.getHeight() - circle.getRadius() ? circle.getCenterY() + 10
                  : circle.getCenterY());
            break;
         case LEFT:
            circle.setCenterX(
                  circle.getCenterX() > circle.getRadius() ? circle.getCenterX() - 10 : circle.getCenterX());
            break;
         case RIGHT:
            circle.setCenterX(circle.getCenterX() < pane.getWidth() - circle.getRadius() ? circle.getCenterX() + 10
                  : circle.getCenterX());
         }
      });

      // Create a scene and place it in the stage
      Scene scene = new Scene(pane, 200, 200);
      primaryStage.setTitle("java2s.com");
      primaryStage.setScene(scene);
      primaryStage.show();

      pane.requestFocus();
   }

}