package com.wpollock.playsnd;

import java.applet.*;
import java.awt.*;
import java.lang.ref.*;
import java.util.*;

/** This applet provides a public "play" method that plays a sound which can
 * be called from JavaScript in the web page.  In addition a cache is
 * kept of previously played sounds.
 *
 * To use this applet you need something like this in your HTML file:<pre>
      &lt;applet name="playSnd" height="0" width="0"
              code="com.wpollock.playsnd.PlaySnd.class"
              archive="PlaySnd.jar"&gt;
         &lt;param name="scriptable" value="true"&gt;
      &lt;/applet&gt;
      &lt;p&gt; A horse says
      &lt;a href="#"
         onClick="document.playSnd.play('whinny.wav'); return false;"
         title="Click to play sound of a horse"&gt;neigh&lt;/a&gt;.
      &lt;/p&gt;
 * </pre>
 *
 * @author Wayne Pollock, Tampa Florida USA.
 * @version 1.0
 * @since 08/08/2004
 */

public class PlaySnd extends Applet
{
   private HashMap cache = new HashMap();

   public void start ()
   {
      // Pre-load the audio classes to make first sound selected play faster.
      // This is done by playing a tiny silent sound file bundled with the
      // applet:
      getAudioClip( getClass().getResource( "silent.wav" ) ).play();
   }

   /**
   * Plays a sound.  Implements a cache of previously loaded sounds.
   *
   * @param sndName The filename or pathname to the sound file, relative to
   *                this applet's JAR file.  (ex: "foo.wav", "audio/foo.wav",
   *                "../media/foo.wav".)
   */

   public void play ( String sndName )
   {
      if ( sndName == null || sndName.length() == 0 )
      {  System.err.println( " PlaySnd.play(): Illegal argument " +
         "(need sound file name)\n" );
         return;  // Nothing to do
      }

      AudioClip snd = null;

      if ( cache.containsKey( sndName ) )
      {  SoftReference sr =  (SoftReference) cache.get( sndName );
         snd = ( sr == null ? null : (AudioClip) sr.get() );
      }
      else
      {  // Since the applet will be deployed from a JAR, using
         // getClass().getResource( sndName ) would not work correctly.
         showStatus( "Loading audio file..." );
         snd = getAudioClip( getCodeBase(), sndName );
         if ( snd == null )
            System.err.println( "PlaySnd.play(): Cannot load sound file \"" +
                                 sndName + "\".\n" );
      }
      if ( snd != null )
      {  snd.play();
         showStatus( "" );
         cache.put( sndName, new SoftReference( snd ) );
      } else
      {  showStatus( "ERROR!  Cannot play sound \"" + sndName + "\"!" );
      }
   }
}