Adding a sound file to a java applet

[Bernard Clark]

I have a simple animation applet: bouncing balls, which compiled and ran without problems. I wanted to add sound to the applet so that when ball hit walls of applet container a sound file was played. When i added sound capability to the applet, it compiled with out problems but crashed when i ran it. Here's the program...

import java.applet.*;
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
import java.net.*;
import javax.sound.sampled.*;

public class BouncingBalls extends JApplet
{
	AudioClip ac;

	public static final int WIDTH = 350;
	public static final int HEIGHT = 300;

	private PaintSurface canvas;


	public void init()
	{
		ac = getAudioClip(getCodeBase(), "explode.au");

		this.setSize(WIDTH, HEIGHT);

		canvas = new PaintSurface();
		this.add(canvas, BorderLayout.CENTER);
		Thread t = new AnimationThread(this);
		t.start();
	}
}

class AnimationThread extends Thread
{

	JApplet c;

	public AnimationThread(JApplet c)
	{
		this.c = c;
	}

	public void run()
	{
		while (true)
		{
			c.repaint();
			try
			{
				Thread.sleep(20);
			}
			catch (InterruptedException ex)
			{
				// swallow the exception
			}
		}
	}
}

class PaintSurface extends JComponent
{

	AudioClip ac;

	int x_pos = 0;     // the starting X position
	int y_pos = 0;     // the starting Y position
	int x_speed = 5;
	int y_speed = 6;
	int d = 20;        // the diameter of the ball
	int width = BouncingBalls.WIDTH;
	int height = BouncingBalls.HEIGHT;

	public void paint(Graphics g)
	{
		Graphics2D g2 = (Graphics2D)g;
		g2.setRenderingHint(
			RenderingHints.KEY_ANTIALIASING,
			RenderingHints.VALUE_ANTIALIAS_ON);

		if(x_pos < 0 || x_pos > width - d)
			{x_speed = -x_speed;
             ac.play();}

		if(y_pos < 0 || y_pos > height - d)
		   {y_speed = -y_speed;
		    ac.play();}


		x_pos += x_speed;
		y_pos += y_speed;

		Shape ball = new Ellipse2D.Float(
			x_pos, y_pos, d, d);
		g2.setColor(Color.RED);
		g2.fill(ball);
	}
}

[Paul Clapham]

Crashed? The best thing to do in that case is to start by looking at the stack trace. You'll find that in the Java console. It should tell you what line of the code threw an exception, and also what the exception was.