Playing Sound File in Java Applet

package com.sun.example;
 
/* From http://java.sun.com/docs/books/tutorial/index.html */
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import java.applet.AudioClip;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.net.URL;
 
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JPanel;
 
public class SoundApplet extends JApplet implements ActionListener, ItemListener {
    AppletSoundList soundList;
 
    String auFile = "spacemusic.au";
 
    String aiffFile = "flute+hrn+mrmba.aif";
 
    String midiFile = "trippygaia1.mid";
 
    String rmfFile = "jungle.rmf";
 
    String wavFile = "bottle-open.wav";
 
    String chosenFile;
 
    AudioClip onceClip, loopClip;
 
    JComboBox formats;
 
    JButton playButton, loopButton, stopButton;
 
    boolean looping = false;
 
    public void init() {
	String[] fileTypes = { auFile, aiffFile, midiFile, rmfFile, wavFile };
	formats = new JComboBox(fileTypes);
	formats.setSelectedIndex(0);
	chosenFile = (String) formats.getSelectedItem();
	formats.addItemListener(this);
 
	playButton = new JButton("Play");
	playButton.addActionListener(this);
 
	loopButton = new JButton("Loop");
	loopButton.addActionListener(this);
 
	stopButton = new JButton("Stop");
	stopButton.addActionListener(this);
	stopButton.setEnabled(false);
 
	JPanel controlPanel = new JPanel();
	controlPanel.add(formats);
	controlPanel.add(playButton);
	controlPanel.add(loopButton);
	controlPanel.add(stopButton);
	getContentPane().add(controlPanel);
 
	startLoadingSounds();
    }
 
    public void itemStateChanged(ItemEvent e) {
	chosenFile = (String) formats.getSelectedItem();
	soundList.startLoading(chosenFile);
    }
 
    void startLoadingSounds() {
	// Start asynchronous sound loading.
	soundList = new AppletSoundList(this, getCodeBase());
	soundList.startLoading(auFile);
	soundList.startLoading(aiffFile);
	soundList.startLoading(midiFile);
	soundList.startLoading(rmfFile);
	soundList.startLoading(wavFile);
    }
 
    public void stop() {
	onceClip.stop(); // Cut short the one-time sound.
	if (looping) {
	    loopClip.stop(); // Stop the sound loop.
	}
    }
 
    public void start() {
	if (looping) {
	    loopClip.loop(); // Restart the sound loop.
	}
    }
 
    public void actionPerformed(ActionEvent event) {
	// PLAY BUTTON
	Object source = event.getSource();
	if (source == playButton) {
	    // Try to get the AudioClip.
	    onceClip = soundList.getClip(chosenFile);
	    onceClip.play(); // Play it once.
	    stopButton.setEnabled(true);
	    showStatus("Playing sound " + chosenFile + ".");
	    if (onceClip == null) {
		showStatus("Sound " + chosenFile + " not loaded yet.");
	    }
	    return;
	}
 
	// START LOOP BUTTON
	if (source == loopButton) {
	    loopClip = soundList.getClip(chosenFile);
 
	    looping = true;
	    loopClip.loop(); // Start the sound loop.
	    loopButton.setEnabled(false); // Disable loop button.
	    stopButton.setEnabled(true);
	    showStatus("Playing sound " + chosenFile + " continuously.");
	    if (loopClip == null) {
		showStatus("Sound " + chosenFile + " not loaded yet.");
	    }
	    return;
	}
 
	// STOP LOOP BUTTON
	if (source == stopButton) {
	    if (looping) {
		looping = false;
		loopClip.stop(); // Stop the sound loop.
		loopButton.setEnabled(true); // Enable start button.
	    } else if (onceClip != null) {
		onceClip.stop();
	    }
	    stopButton.setEnabled(false);
	    showStatus("Stopped playing " + chosenFile + ".");
	    return;
	}
    }
}
 
// Loads and holds a bunch of audio files whose locations are specified
// relative to a fixed base URL.
 
class AppletSoundList extends java.util.Hashtable {
    JApplet applet;
 
    URL baseURL;
 
    public AppletSoundList(JApplet applet, URL baseURL) {
	super(5); // Initialize Hashtable with capacity of 5 entries.
	this.applet = applet;
	this.baseURL = baseURL;
    }
 
    public void startLoading(String relativeURL) {
	new AppletSoundLoader(applet, this, baseURL, relativeURL);
    }
 
    public AudioClip getClip(String relativeURL) {
	return (AudioClip) get(relativeURL);
    }
 
    public void putClip(AudioClip clip, String relativeURL) {
	put(relativeURL, clip);
    }
}
 
class AppletSoundLoader extends Thread {
    JApplet applet;
 
    AppletSoundList soundList;
 
    URL baseURL;
 
    String relativeURL;
 
    public AppletSoundLoader(JApplet applet, AppletSoundList soundList, URL baseURL, String relativeURL) {
	this.applet = applet;
	this.soundList = soundList;
	this.baseURL = baseURL;
	this.relativeURL = relativeURL;
	setPriority(MIN_PRIORITY);
	start();
    }
 
    public void run() {
	AudioClip audioClip = applet.getAudioClip(baseURL, relativeURL);
	soundList.putClip(audioClip, relativeURL);
    }
}