(Racing car) Write a program that simulates car racing, as shown in Figure 15.34a

/*********************************************************************************
* (Racing car) Write a program that simulates car racing, as shown in Figure     *
* 15.34a. The car moves from left to right. When it hits the right end, it       *
* restarts from the left and continues the same process. You can use a timer to  *
* control animation. Redraw the car with a new base coordinates (x, y), as shown *
* in Figure 15.34b. Also let the user pause/resume the animation with a button   *
* press/release and increase/decrease the car speed by pressing the UP and       *
* DOWN arrow keys.                                                               *
*********************************************************************************/
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.input.KeyCode;

public class Exercise_15_29 extends Application {
	@Override // Override the start method on the Application class
	public void start(Stage primaryStage) {
		// Create a car
		CarPane pane = new CarPane();

		// Create and register handles
		pane.setOnMousePressed(e -> pane.pause());
		pane.setOnMouseReleased(e -> pane.play());

		pane.setOnKeyPressed(e -> {
			if (e.getCode() == KeyCode.UP) {
				pane.increaseSpeed();
			}
			else if (e.getCode() == KeyCode.DOWN) {
				pane.decreaseSpeed();
			}
		});

		// Create a scene and place it in the stage
		Scene scene = new Scene(pane, 600, 100);
		primaryStage.setTitle("Exercise_15_29"); // Set the stage title
		primaryStage.setScene(scene); // Place the scene in the stage
		primaryStage.show(); // Display the stage

		pane.requestFocus(); // Request focus
	}
}

CarPane.java

import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Polygon;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.Circle;
import javafx.scene.paint.Color;
import javafx.util.Duration;

public class CarPane extends Pane {
	private double x = 0;
	private double y = 100;
	private double radius = 5;
	private Rectangle rectangle;
	private Polygon polygon;
	private Circle circle1;
	private Circle circle2;
	private Timeline animation;

	/** Construct and animate a default CarPane */
	CarPane() {
		drawCar();
		animation = new Timeline(
			new KeyFrame(Duration.millis(50), e -> moveCar()));
		animation.setCycleCount(Timeline.INDEFINITE);
		animation.play();
	}

	/** Create a car an place it in the pane */
	private void drawCar() {
		getChildren().clear();
		rectangle = new Rectangle(x, y - 20, 50, 10);
		polygon = new Polygon(x + 10, y - 20, x + 20, y - 30, x + 30, 
			y - 30, x + 40, y - 20);
		circle1 = new Circle(x + 15, y - 5, radius);
		circle2 = new Circle(x + 35, y - 5, radius);
		getChildren().addAll(rectangle, circle1, circle2, polygon);
	}

	/** Pause animation */
	public void pause() {
		animation.pause();
	}

	/** Play animation */
	public void play() {
		animation.play();
	}

	/** Increase rate by 1 */
	public void increaseSpeed() {
		animation.setRate(animation.getRate() + 1);
	}

	/** decrease rate by 1 */
	public void decreaseSpeed() {
		animation.setRate(animation.getRate() > 0 ? animation.getRate() - 1 : 0);
	}

	/** Redraw car with new x value */
	protected void moveCar() {
		if (x <= getWidth()) {
			x += 1;	
		} 
		else
			x = 0;

		drawCar();
	}
}