/* Applet.java -- Java base applet class   Copyright (C) 1999, 2002, 2004, 2005  Free Software Foundation, Inc.This file is part of GNU Classpath.GNU Classpath is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2, or (at your option)any later version.GNU Classpath is distributed in the hope that it will be useful, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNUGeneral Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Classpath; see the file COPYING.  If not, write to theFree Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA02110-1301 USA.Linking this library statically or dynamically with other modules ismaking a combined work based on this library.  Thus, the terms andconditions of the GNU General Public License cover the wholecombination.As a special exception, the copyright holders of this library give youpermission to link this library with independent modules to produce anexecutable, regardless of the license terms of these independentmodules, and to copy and distribute the resulting executable underterms of your choice, provided that you also meet, for each linkedindependent module, the terms and conditions of the license of thatmodule.  An independent module is a module which is not derived fromor based on this library.  If you modify this library, you may extendthis exception to your version of the library, but you are notobligated to do so.  If you do not wish to do so, delete thisexception statement from your version. */package java.applet;import java.awt.Component;import java.awt.Dimension;import java.awt.GraphicsEnvironment;import java.awt.HeadlessException;import java.awt.Image;import java.awt.Panel;import java.io.IOException;import java.io.ObjectInputStream;import java.net.MalformedURLException;import java.net.URL;import java.util.Locale;import javax.accessibility.AccessibleContext;import javax.accessibility.AccessibleRole;import javax.accessibility.AccessibleState;import javax.accessibility.AccessibleStateSet;import javax.sound.sampled.AudioSystem;import javax.sound.sampled.Clip;import javax.sound.sampled.LineUnavailableException;import javax.sound.sampled.UnsupportedAudioFileException;/** * This is the base applet class.  An applet is a Java program that * runs inside a web browser or other applet viewer in a restricted * environment. * * <p>To be useful, a subclass should override at least start(). Also useful * are init, stop, and destroy for control purposes, and getAppletInfo and * getParameterInfo for descriptive purposes. * * @author Aaron M. Renn (arenn@urbanophile.com) * @author Eric Blake (ebb9@email.byu.edu) * @since 1.0 * @status updated to 1.4 */public class Applet extends Panel{  /**   * Compatible with JDK 1.0+.   */  private static final long serialVersionUID = -5836846270535785031L;  /** The applet stub for this applet. */  private transient AppletStub stub;  /** Some applets call setSize in their constructors.  In that case,      these fields are used to store width and height values until a      stub is set. */  private transient int width;  private transient int height;  /**   * The accessibility context for this applet.   *   * @serial the accessibleContext for this   * @since 1.2   */  private AccessibleContext accessibleContext;  /**   * Default constructor for subclasses.   *   * @throws HeadlessException if in a headless environment   */  public Applet()  {    if (GraphicsEnvironment.isHeadless())      throw new HeadlessException();  }  /**   * The browser calls this method to set the applet's stub, which is the   * low level interface to the browser. Manually setting this to null is   * asking for problems down the road.   *   * @param stub the applet stub for this applet   */  public final void setStub(AppletStub stub)  {    this.stub = stub;    if (width != 0 && height != 0)      stub.appletResize (width, height);  }  /**   * Tests whether or not this applet is currently active. An applet is active   * just before the browser invokes start(), and becomes inactive just   * before the browser invokes stop().   *   * @return <code>true</code> if this applet is active   */  public boolean isActive()  {    return stub.isActive();  }  /**   * Returns the basename URL of the document this applet is embedded in. This   * is everything up to the final '/'.   *   * @return the URL of the document this applet is embedded in   * @see #getCodeBase()   */  public URL getDocumentBase()  {    return stub.getDocumentBase();  }  /**   * Returns the URL of the code base for this applet.   *   * @return the URL of the code base for this applet   */  public URL getCodeBase()  {    return stub.getCodeBase();  }  /**   * Returns the value of the specified parameter that was specified in   * the <code>&lt;APPLET&gt;</code> tag for this applet.   *   * @param name the parameter name   * @return the parameter value, or null if the parameter does not exist   * @throws NullPointerException if name is null   */  public String getParameter(String name)  {    return stub.getParameter(name);  }  /**   * Returns the applet context for this applet.   *   * @return the applet context for this applet   */  public AppletContext getAppletContext()  {    return stub.getAppletContext();  }  /**   * Requests that the applet window for this applet be resized.   *   * @param width the new width in pixels   * @param height the new height in pixels   */  public void resize(int width, int height)  {    if (stub == null)      {        this.width = width;        this.height = height;      }    else      stub.appletResize(width, height);  }  /**   * Requests that the applet window for this applet be resized.   *   * @param dim the requested dimensions   * @throws NullPointerException if dim is null   */  public void resize(Dimension dim)  {    resize(dim.width, dim.height);  }  /**   * Displays the specified message in the status window if that window   * exists.   *   * @param message the status message, may be null   */  public void showStatus(String message)  {    getAppletContext().showStatus(message);  }  /**   * Returns an image from the specified URL.  Note that the image is not   * actually retrieved until the applet attempts to display it, so this   * method returns immediately.   *   * @param url the URL of the image   * @return the retrieved image   * @throws NullPointerException if url is null   */  public Image getImage(URL url)  {    return getAppletContext().getImage(url);  }  /**   * Returns an image from the specified absolute URL, and relative path   * from that URL.  Note that the image is not actually retrieved until the   * applet attempts to display it, so this method returns immediately.   * This calls <code>getImage(new URL(url, name))</code>, but if building   * the new URL fails, this returns null.   *   * @param url the base URL of the image   * @param name the name of the image relative to the URL   * @return the retrieved image, or null on failure   * @see #getImage(URL)   */  public Image getImage(URL url, String name)  {    try      {	return getImage(new URL(url, name));      }    catch (MalformedURLException e)      {	return null;      }  }  /**   * Returns an audio clip from the specified URL. This clip is not tied to   * any particular applet.   *   * @param url the URL of the audio clip   * @return the retrieved audio clip   * @throws NullPointerException if url is null   * @see #getAudioClip(URL)   * @since 1.2   */  public static final AudioClip newAudioClip(URL url)  {    return new URLAudioClip(url);  }  /**   * Returns an audio clip from the specified URL. Note that the clip is not   * actually retrieved until the applet attempts to play it, so this method   * returns immediately.   *   * @param url the URL of the audio clip   * @return the retrieved audio clip   * @throws NullPointerException if url is null   */  public AudioClip getAudioClip(URL url)  {    return getAppletContext().getAudioClip(url);  }  /**   * Returns an audio clip from the specified absolute URL, and relative path   * from that URL.  Note that the clip is not actually retrieved until the   * applet attempts to play it, so this method returns immediately. This   * calls <code>getAudioClip(new URL(url, name))</code>, but if building   * the new URL fails, this returns null.   *   * @param url the base URL of the audio clip   * @param name the name of the clip relative to the URL