GameArena.java

import java.util.*;
import java.util.Collections;
import javafx.scene.input.KeyEvent;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javafx.application.Platform;
import javafx.animation.AnimationTimer;
import javafx.embed.swing.JFXPanel;
import javafx.event.*;
import javafx.scene.*;
import javafx.scene.paint.*;
import javafx.scene.layout.*;
import javafx.scene.control.*;
import javafx.scene.input.KeyCode;

import java.awt.event.WindowEvent;

/**
 * This class provides a simple window in which grahical objects can be drawn.
 *
 * Instances of the Ball and Rectangle classes can be added to an instance of this class to
 * draw and animate simple shapes on the screen.
 *
 * @see Ball
 * @see Rectangle
 *
 * @author Joe Finney
 */
public class GameArena
{
	// Size of window
	private int arenaWidth;
	private int arenaHeight;
    private JFrame window;

	private boolean exiting = false;
    private final static int MAXIMUM_OBJECTS = 100000;

    // Collections of primitives. These now relate 1:1 to JavaFX Nodes, since moving from AWT.
    private List<Object> addList = new ArrayList<Object>();
    private List<Object> removeList = new ArrayList<Object>();
    private Map<Ball, javafx.scene.shape.Circle> balls = new HashMap<>();
    private Map<Rectangle, javafx.scene.shape.Rectangle> rectangles = new HashMap<>();
    private int objectCount;

    // Basic button state
	private boolean up = false;
	private boolean down = false;
	private boolean left = false;
	private boolean right = false;

    // JavaFX containers
    private Scene scene;
    private Group root;
    private JFXPanel jfxPanel;

	/**
     * Constructor. Creates an instance of the GameArena class, and displays a window on the
     * screen upon which shapes can be drawn.
     *
     * @param width The width of the window, in pixels.
     * @param height The height of the window, in pixels.
	 */
	public GameArena(int width, int height)
	{
        this.arenaWidth = width;
        this.arenaHeight = height;
        this.objectCount = 0;

        // Create a window
        window = new JFrame();
        window.setTitle("Let's Play!");

        // Create a JavaFX canvas as a Swing panel.
        jfxPanel = new JFXPanel();
        jfxPanel.setPreferredSize(new java.awt.Dimension(width, height));

        window.setContentPane(jfxPanel);
        window.setResizable(false);
        window.pack();
        window.setVisible(true);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        root = new Group();
        scene = new Scene(root, arenaWidth, arenaHeight, Color.BLACK);

        Platform.runLater(new Runnable() {
            @Override
            public void run() {
                initFX();
            }
        });
	}

	public void changeTitle(String title)
	{
		window.setTitle(title);
	}

   private void initFX() {

        EventHandler<KeyEvent> keyDownHandler = new EventHandler<KeyEvent>() {
            public void handle(final KeyEvent keyEvent) {
                if (keyEvent.getCode() == KeyCode.UP)
                    up = true;
                if (keyEvent.getCode() == KeyCode.DOWN)
                    down = true;
                if (keyEvent.getCode() == KeyCode.LEFT)
                    left = true;
                if (keyEvent.getCode() == KeyCode.RIGHT)
                    right = true;
            }
        };

        EventHandler<KeyEvent> keyUpHandler = new EventHandler<KeyEvent>() {
            public void handle(final KeyEvent keyEvent) {
                if (keyEvent.getCode() == KeyCode.UP)
                    up = false;
                if (keyEvent.getCode() == KeyCode.DOWN)
                    down = false;
                if (keyEvent.getCode() == KeyCode.LEFT)
                    left = false;
                if (keyEvent.getCode() == KeyCode.RIGHT)
                    right = false;
            }
        };

        scene.setOnKeyPressed(keyDownHandler);
        scene.setOnKeyReleased(keyUpHandler);

        jfxPanel.setScene(scene);

        new AnimationTimer() {
            @Override
            public void handle(long now) {
                frameUpdate();
            }
        }.start();
    }

	/**
	 * Close this GameArena window.
	 *
	 */
	public void exit()
	{
		this.exiting = true;
        window.dispatchEvent(new WindowEvent(window, WindowEvent.WINDOW_CLOSING));
	}

	/**
	 * A method called by the operating system to draw onto the screen - <p><B>YOU DO NOT (AND SHOULD NOT) NEED TO CALL THIS METHOD.</b></p>
	 */
	private void frameUpdate ()
    {
        if (!this.exiting)
        {
            // Remove any deleted objects from the scene.
            synchronized (this)
            {
                for (Object o: removeList)
                {
                    if (o instanceof Ball)
                    {
                        Ball b = (Ball) o;
                        javafx.scene.shape.Circle c = balls.get(b);
                        root.getChildren().remove(c);

                        balls.remove(b);
                    }

                    if (o instanceof Rectangle)
                    {
                        Rectangle r = (Rectangle) o;
                        javafx.scene.shape.Rectangle rectangle = rectangles.get(r);
                        root.getChildren().remove(rectangle);

                        rectangles.remove(r);
                    }
                }

                removeList.clear();

                // Add any new objects to the scene.
                for (Object o: addList)
                {
                    if (o instanceof Ball)
                    {
                        Ball b = (Ball) o;
                        javafx.scene.shape.Circle c = new javafx.scene.shape.Circle(0,0,b.getSize());
                        root.getChildren().add(c);
                        balls.put(b, c);
                    }

                    if (o instanceof Rectangle)
                    {
                        Rectangle r = (Rectangle) o;
                        javafx.scene.shape.Rectangle rectangle = new javafx.scene.shape.Rectangle(0, 0, r.getWidth(), r.getHeight());
                        root.getChildren().add(rectangle);
                        rectangles.put(r, rectangle);
                    }
                }

                addList.clear();
            }

            for(Map.Entry<Ball, javafx.scene.shape.Circle> entry : balls.entrySet())
            {
                Ball b = entry.getKey();
                javafx.scene.shape.Circle c = entry.getValue();

                c.setRadius(b.getSize());
                c.setTranslateX(b.getXPosition());
                c.setTranslateY(b.getYPosition());
                c.setFill(getColourFromString(b.getColour()));
            }

            for(Map.Entry<Rectangle, javafx.scene.shape.Rectangle> entry : rectangles.entrySet())
            {
                Rectangle r = entry.getKey();
                javafx.scene.shape.Rectangle rectangle = entry.getValue();

                rectangle.setTranslateX(r.getXPosition() - r.getWidth()/2);
                rectangle.setTranslateY(r.getYPosition() - r.getHeight()/2);
                rectangle.setFill(getColourFromString(r.getColour()));
            }
        }
    }

	//
    // Derive a Color object from a given string representation
	//
	private Color getColourFromString(String col)
	{
		Color colour = Color.web(col);
		return colour;
	}

	/**
	 * Adds a given Ball to the GameArena.
	 * Once a Ball is added, it will automatically appear on the window.
	 *
	 * @param b the ball to add to the GameArena.
	 */
	public void addBall(Ball b)
	{
		synchronized (this)
		{
			if (objectCount > MAXIMUM_OBJECTS)
			{
				System.out.println("\n\n");
				System.out.println(" ********************************************************* ");
				System.out.println(" ***** Only 100000 Objects Supported per Game Arena! ***** ");
				System.out.println(" ********************************************************* ");
				System.out.println("\n");
				System.out.println("-- Joe\n\n");

                System.exit(0);
			}

            // Add this ball to the draw list. Initially, with a null JavaFX entry, which we'll fill in later to avoid cross-thread operations...
            removeList.remove(b);
            addList.add(b);
            objectCount++;
		}
	}

	/**
	 * Remove a Ball from the GameArena.
	 * Once a Ball is removed, it will no longer appear on the window.
	 *
	 * @param b the ball to remove from the GameArena.
	 */
	public void removeBall(Ball b)
	{
		synchronized (this)
		{
            addList.remove(b);
            removeList.add(b);
            objectCount--;
		}
	}

	/**
	 * Adds a given rectangle to the GameArena.
	 * Once a Rectangle is added, it will automatically appear on the window.
	 *
	 * @param r the rectangle to add to the GameArena.
	 */
	public void addRectangle(Rectangle r)
	{
		synchronized (this)
		{
			if (objectCount > MAXIMUM_OBJECTS)
			{
				System.out.println("\n\n");
				System.out.println(" ********************************************************* ");
				System.out.println(" ***** Only 100000 Objects Supported per Game Arena! ***** ");
				System.out.println(" ********************************************************* ");
				System.out.println("\n");
				System.out.println("-- Joe\n\n");

                System.exit(0);
			}

            // Add this ball to the draw list. Initially, with a null JavaFX entry, which we'll fill in later to avoid cross-thread operations...
            removeList.remove(r);
            addList.add(r);
            objectCount++;
		}
	}

	/**
	 * Remove a Rectangle from the GameArena.
	 * Once a Rectangle is removed, it will no longer appear on the window.
	 *
	 * @param r the rectangle to remove from the GameArena.
	 */
	public void removeRectangle(Rectangle r)
	{
		synchronized (this)
		{
            addList.remove(r);
            removeList.add(r);
            objectCount--;
		}
	}

	/**
	 * Pause for a 1/50 of a second.
	 * This method causes your program to delay for 1/50th of a second. You'll find this useful if you're trying to animate your application.
	 */
	public void pause()
	{
		try { Thread.sleep(18); }
		catch (Exception e) {};
	}

	/**
	 * Gets the width of the GameArena window, in pixels.
	 * @return the width in pixels
	 */
	public int getArenaWidth()
	{
		return arenaWidth;
	}

	/**
	 * Gets the height of the GameArena window, in pixels.
	 * @return the height in pixels
	 */
	public int getArenaHeight()
	{
		return arenaHeight;
	}

	/**
	 * Determines if the user is currently pressing the cursor up button.
	 * @return true if the up button is pressed, false otherwise.
	 */
	public boolean upPressed()
	{
		return up;
	}

	/**
	 * Determines if the user is currently pressing the cursor down button.
	 * @return true if the down button is pressed, false otherwise.
	 */
	public boolean downPressed()
	{
		return down;
	}

	/**
	 * Determines if the user is currently pressing the cursor left button.
	 * @return true if the left button is pressed, false otherwise.
	 */
	public boolean leftPressed()
	{
		return left;
	}

	/**
	 * Determines if the user is currently pressing the cursor right button.
	 * @return true if the right button is pressed, false otherwise.
	 */
	public boolean rightPressed()
	{
		return right;
	}
}