applet.java

gcc的组建

   * @return the retrieved audio clip, or null on failure
   * @see #getAudioClip(URL)
   */
  public AudioClip getAudioClip(URL url, String name)
  {
    try
      {
	return getAudioClip(new URL(url, name));
      }
    catch (MalformedURLException e)
      {
	return null;
      }
  }

  /**
   * Returns a descriptive string with applet defined information.  The
   * implementation in this class returns <code>null</code>, so subclasses
   * must override to return information.
   *
   * @return a string describing the author, version, and applet copyright
   */
  public String getAppletInfo()
  {
    return null;
  }

  /**
   * Returns the locale for this applet, if it has been set.  If no applet
   * specific locale has been set, the default locale is returned.
   *
   * @return the locale for this applet
   * @see Component#setLocale(Locale)
   * @since 1.1
   */
  public Locale getLocale()
  {
    return super.getLocale();
  }

  /**
   * Returns a list of parameters this applet supports.  Each element of
   * the outer array is an array of three strings with the name of the
   * parameter, the data type or valid values, and a description.  This
   * method is optional and the default implementation returns null.
   *
   * @return the list of parameters supported by this applet
   */
  public String[][] getParameterInfo()
  {
    return null;
  }

  /**
   * Loads and plays the audio clip pointed to by the specified URL. This does
   * nothing if the URL does not point to a valid audio clip.
   *
   * @param url the URL of the audio clip
   * @throws NullPointerException if url is null
   * @see #getAudioClip(URL)
   */
  public void play(URL url)
  {
    AudioClip ac = getAudioClip(url);
    try
      {
	ac.play();
      }
    catch (Exception ignored)
      {
      }
  }

  /**
   * Loads and plays the audio clip pointed to by the specified absolute URL,
   * and relative path from that URL. This does nothing if the URL cannot be
   * constructed, or if it does not point to a valid audio clip.
   *
   * @param url the base URL of the audio clip
   * @param name the name of the audio clip relative to the URL
   * @see #getAudioClip(URL, String)
   * @see #play(URL)
   */
  public void play(URL url, String name)
  {
    try
      {
	getAudioClip(url, name).play();
      }
    catch (Exception ignored)
      {
      }
  }

  /**
   * This method is called when the applet is first loaded, before start().
   * The default implementation does nothing; override to do any one-time
   * initialization.
   *
   * @see #start()
   * @see #stop()
   * @see #destroy()
   */
  public void init()
  {
  }

  /**
   * This method is called when the applet should start running.  This is
   * normally each time a web page containing it is loaded.  The default
   * implemention does nothing; override for your applet to be useful.
   *
   * @see #init()
   * @see #stop()
   * @see #destroy()
   */
  public void start()
  {
  }

  /**
   * This method is called when the applet should stop running.  This is
   * normally when the next web page is loaded.  The default implementation
   * does nothing; override for your applet to stop using resources when
   * it is no longer visible, but may be restarted soon.
   *
   * @see #init()
   * @see #start()
   * @see #destroy()
   */
  public void stop()
  {
  }

  /**
   * This method is called when the applet is being unloaded.  The default
   * implementation does nothing; override for your applet to clean up
   * resources on exit.
   *
   * @see #init()
   * @see #start()
   * @see #stop()
   */
  public void destroy()
  {
  }

  /**
   * Gets the AccessibleContext associated with this applet, creating one if
   * necessary. This always returns an instance of {@link AccessibleApplet}.
   *
   * @return the accessibility context of this applet
   * @since 1.3
   */
  public AccessibleContext getAccessibleContext()
  {
    if (accessibleContext == null)
      accessibleContext = new AccessibleApplet();
    return accessibleContext;
  }

  /**
   * Read an applet from an object stream. This checks for a headless
   * environment, then does the normal read.
   *
   * @param s the stream to read from
   * @throws ClassNotFoundException if a class is not found
   * @throws IOException if deserialization fails
   * @throws HeadlessException if this is a headless environment
   * @see GraphicsEnvironment#isHeadless()
   * @since 1.4
   */
  private void readObject(ObjectInputStream s)
    throws ClassNotFoundException, IOException
  {
    if (GraphicsEnvironment.isHeadless())
      throw new HeadlessException();
    s.defaultReadObject();
  }

  /**
   * This class provides accessibility support for Applets, and is the
   * runtime type returned by {@link #getAccessibleContext()}.
   *
   * @author Eric Blake ([e-mail])
   * @since 1.3
   */
  protected class AccessibleApplet extends AccessibleAWTPanel
  {
    /**
     * Compatible with JDK 1.4+.
     */
    private static final long serialVersionUID = 8127374778187708896L;

    /**
     * The default constructor.
     */
    protected AccessibleApplet()
    {
    }

    /**
     * Get the role of this accessible object, a frame.
     *
     * @return the role of the object
     * @see AccessibleRole#FRAME
     */
    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.FRAME;
    }

    /**
     * Get the state set of this accessible object. In addition to the default
     * states of a Component, the applet can also be active.
     *
     * @return the role of the object
     * @see AccessibleState
     */
    public AccessibleStateSet getAccessibleStateSet()
    {
      AccessibleStateSet s = super.getAccessibleStateSet();
      if (isActive())
	s.add(AccessibleState.ACTIVE);
      return s;
    }
  } // class AccessibleApplet

  private static class URLAudioClip implements AudioClip
  {
    // The URL we will try to play.
    // This is null if we have already tried to create an
    // audio input stream from this URL.
    private URL url;

    // The real audio clip.  This is null before the URL is read,
    // and might be null afterward if we were unable to read the URL
    // for some reason.
    private Clip clip;
    
    public URLAudioClip(URL url)
    {
      this.url = url;
    }

    private synchronized Clip getClip()
    {
      if (url == null)
        return clip;
      try
        {
          clip = AudioSystem.getClip();
          clip.open(AudioSystem.getAudioInputStream(url));
        }
      catch (LineUnavailableException _)
        {
          // Ignore.
        }
      catch (IOException _)
        {
          // Ignore.
        }
      catch (UnsupportedAudioFileException _)
        {
          // Ignore.
        }
      url = null;
      return clip;
    }

    public void loop()
    {
      Clip myclip = getClip();
      if (myclip != null)
        myclip.loop(Clip.LOOP_CONTINUOUSLY);
    }

    public void play()
    {
      Clip myclip = getClip();
      if (myclip != null)
        myclip.start();
    }

    public void stop()
    {
      Clip myclip = getClip();
      if (myclip != null)
        {
          myclip.stop();
          myclip.setFramePosition(0);
        }
    }
  }
} // class Applet