/*
* @(#)Applet.java 1.54 06/10/16
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package java.applet;
import java.awt.*;
import java.awt.image.ColorModel;
import java.net.URL;
import java.net.MalformedURLException;
import java.util.Hashtable;
import java.util.Locale;
//import javax.accessibility.*;
/**
* An applet is a small program that is intended not to be run on
* its own, but rather to be embedded inside another application.
* <p>
* The <code>Applet</code> class must be the superclass of any
* applet that is to be embedded in a Web page or viewed by the Java
* Applet Viewer. The <code>Applet</code> class provides a standard
* interface between applets and their environment.
*
* @author Arthur van Hoff
* @author Chris Warth
* @version 1.49, 08/21/02
* @since JDK1.0
*/
public class Applet extends Panel {
/**
* Applets can be serialized but the following conventions MUST be followed:
*
* Before Serialization:
* An applet must be in STOPPED state.
*
* After Deserialization:
* The applet will be restored in STOPPED state (and most clients will
* likely move it into RUNNING state).
* The stub field will be restored by the reader.
*/
transient private AppletStub stub;
/* version ID for serialized form. */
private static final long serialVersionUID = -5836846270535785031L;
/**
* Sets this applet's stub. This is done automatically by the system.
*
* @param stub the new stub.
*/
public final void setStub(AppletStub stub) {
this.stub = (AppletStub) stub;
}
/**
* Determines if this applet is active. An applet is marked active
* just before its <code>start</code> method is called. It becomes
* inactive just before its <code>stop</code> method is called.
*
* @return <code>true</code> if the applet is active;
* <code>false</code> otherwise.
* @see java.applet.Applet#start()
* @see java.applet.Applet#stop()
*/
public boolean isActive() {
if (stub != null) {
return stub.isActive();
} else { // If stub field not filled in, applet never active
return false;
}
}
/**
* Returns an absolute URL naming the directory of the document in which
* the applet is embedded. For example, suppose an applet is contained
* within the document:
* <blockquote><pre>
* http://java.sun.com/products/jdk/1.2/index.html
* </pre></blockquote>
* The document base is:
* <blockquote><pre>
* http://java.sun.com/products/jdk/1.2/
* </pre></blockquote>
*
* @return the {@link java.net.URL} of the document that contains this
* applet.
* @see java.applet.Applet#getCodeBase()
*/
public URL getDocumentBase() {
return stub.getDocumentBase();
}
/**
* Gets the base URL. This is the URL of the applet itself.
*
* @return the {@link java.net.URL} of
* this applet.
* @see java.applet.Applet#getDocumentBase()
*/
public URL getCodeBase() {
return stub.getCodeBase();
}
/**
* Returns the value of the named parameter in the HTML tag. For
* example, if this applet is specified as
* <blockquote><pre>
* <applet code="Clock" width=50 height=50>
* <param name=Color value="blue">
* </applet>
* </pre></blockquote>
* <p>
* then a call to <code>getParameter("Color")</code> returns the
* value <code>"blue"</code>.
* <p>
* The <code>name</code> argument is case insensitive.
*
* @param name a parameter name.
* @return the value of the named parameter,
* or <code>null</code> if not set.
*/
public String getParameter(String name) {
return stub.getParameter(name);
}
/**
* Determines this applet's context, which allows the applet to
* query and affect the environment in which it runs.
* <p>
* This environment of an applet represents the document that
* contains the applet.
*
* @return the applet's context.
*/
public AppletContext getAppletContext() {
return stub.getAppletContext();
}
/**
* Requests that this applet be resized.
*
* @param width the new requested width for the applet.
* @param height the new requested height for the applet.
*/
public void resize(int width, int height) {
Dimension d = size();
if ((d.width != width) || (d.height != height)) {
super.resize(width, height);
if (stub != null) {
stub.appletResize(width, height);
}
}
}
/**
* Requests that this applet be resized.
*
* @param d an object giving the new width and height.
*/
public void resize(Dimension d) {
resize(d.width, d.height);
}
/**
* Requests that the argument string be displayed in the
* "status window". Many browsers and applet viewers
* provide such a window, where the application can inform users of
* its current state.
*
* @param msg a string to display in the status window.
*/
public void showStatus(String msg) {
getAppletContext().showStatus(msg);
}
/**
* Returns an <code>Image</code> object that can then be painted on
* the screen. The <code>url</code> that is passed as an argument
* must specify an absolute URL.
* <p>
* This method always returns immediately, whether or not the image
* exists. When this applet attempts to draw the image on the screen,
* the data will be loaded. The graphics primitives that draw the
* image will incrementally paint on the screen.
*
* @param url an absolute URL giving the location of the image.
* @return the image at the specified URL.
* @see java.awt.Image
*/
public Image getImage(URL url) {
return getAppletContext().getImage(url);
}
/**
* Returns an <code>Image</code> object that can then be painted on
* the screen. The <code>url</code> argument must specify an absolute
* URL. The <code>name</code> argument is a specifier that is
* relative to the <code>url</code> argument.
* <p>
* This method always returns immediately, whether or not the image
* exists. When this applet attempts to draw the image on the screen,
* the data will be loaded. The graphics primitives that draw the
* image will incrementally paint on the screen.
*
* @param url an absolute URL giving the base location of the image.
* @param name the location of the image, relative to the
* <code>url</code> argument.
* @return the image at the specified URL.
* @see java.awt.Image
*/
public Image getImage(URL url, String name) {
/* Adding a getResource() call below in order to enable
* loading of images located inside a jar file. This change
* causes this method not to conform to JDK spec. Related bug
* IDs are 4157932, 4159155 & 4214785 that allude to the correct
* behaviour in JDK.
*/
URL u = this.getClass().getResource(name);
if (u != null) {
return getImage(u);
} else {
try {
return getImage(new URL(url, name));
} catch (MalformedURLException e) {
return null;
}
}
}
/**
* Get an audio clip from the given URL.
*
* @param url points to the audio clip
* @return the audio clip at the specified URL.
*
* @since 1.2
*/
public final static AudioClip newAudioClip(URL url) {
return new sun.applet.AppletAudioClip(url);
}
/**
* Returns the <code>AudioClip</code> object specified by the
* <code>URL</code> argument.
* <p>
* This method always returns immediately, whether or not the audio
* clip exists. When this applet attempts to play the audio clip, the
* data will be loaded.
*
* @param url an absolute URL giving the location of the audio clip.
* @return the audio clip at the specified URL.
* @see java.applet.AudioClip
*/
public AudioClip getAudioClip(URL url) {
return getAppletContext().getAudioClip(url);
}
/**
* Returns the <code>AudioClip</code> object specified by the
* <code>URL</code> and <code>name</code> arguments.
* <p>
* This method always returns immediately, whether or not the audio
* clip exists. When this applet attempts to play the audio clip, the
* data will be loaded.
*
* @param url an absolute URL giving the base location of the
* audio clip.
* @param name the location of the audio clip, relative to the
* <code>url</code> argument.
* @return the audio clip at the specified URL.
* @see java.applet.AudioClip
*/
public AudioClip getAudioClip(URL url, String name) {
try {
return getAudioClip(new URL(url, name));
} catch (MalformedURLException e) {
return null;
}
}
/**
* Returns information about this applet. An applet should override
* this method to return a <code>String</code> containing information
* about the author, version, and copyright of the applet.
* <p>
* The implementation of this method provided by the
* <code>Applet</code> class returns <code>null</code>.
*
* @return a string containing information about the author, version, and
* copyright of the applet.
*/
public String getAppletInfo() {
return null;
}
/**
* Gets the Locale for the applet, if it has been set.
* If no Locale has been set, then the default Locale
* is returned.
*
* @return the Locale for the applet
* @since JDK1.1
*/
public Locale getLocale() {
Locale locale = super.getLocale();
if (locale == null) {
return Locale.getDefault();
}
return locale;
}
/**
* Returns information about the parameters than are understood by
* this applet. An applet should override this method to return an
* array of <code>Strings</code> describing these parameters.
* <p>
* Each element of the array should be a set of three
* <code>Strings</code> containing the name, the type, and a
* description. For example:
* <p><blockquote><pre>
* String pinfo[][] = {
* {"fps", "1-10", "frames per second"},
* {"repeat", "boolean", "repeat image loop"},
* {"imgs", "url", "images directory"}
* };
* </pre></blockquote>
* <p>
* The implementation of this method provided by the
* <code>Applet</code> class returns <code>null</code>.
*
* @return an array describing the parameters this applet looks for.
*/
public String[][] getParameterInfo() {
return null;
}
/**
* Plays the audio clip at the specified absolute URL. Nothing
* happens if the audio clip cannot be found.
*
* @param url an absolute URL giving the location of the audio clip.
*/
public void play(URL url) {
AudioClip clip = getAudioClip(url);
if (clip != null) {
clip.play();
}
}
/**
* Plays the audio clip given the URL and a specifier that is
* relative to it. Nothing happens if the audio clip cannot be found.
*
* @param url an absolute URL giving the base location of the
* audio clip.
* @param name the location of the audio clip, relative to the
* <code>url</code> argument.
*/
public void play(URL url, String name) {
AudioClip clip = getAudioClip(url, name);
if (clip != null) {
clip.play();
}
}
/**
* Called by the browser or applet viewer to inform
* this applet that it has been loaded into the system. It is always
* called before the first time that the <code>start</code> method is
* called.
* <p>
* A subclass of <code>Applet</code> should override this method if
* it has initialization to perform. For example, an applet with
* threads would use the <code>init</code> method to create the
* threads and the <code>destroy</code> method to kill them.
* <p>
* The implementation of this method provided by the
* <code>Applet</code> class does nothing.
*
* @see java.applet.Applet#destroy()
* @see java.applet.Applet#start()
* @see java.applet.Applet#stop()
*/
public void init() {}
/**
* Called by the browser or applet viewer to inform
* this applet that it should start its execution. It is called after
* the <code>init</code> method and each time the applet is revisited
* in a Web page.
* <p>
* A subclass of <code>Applet</code> should override this method if
* it has any operation that it wants to perform each time the Web
* page containing it is visited. For example, an applet with
* animation might want to use the <code>start</code> method to
* resume animation, and the <code>stop</code> method to suspend the
* animation.
* <p>
* The implementation of this method provided by the
* <code>Applet</code> class does nothing.
*
* @see java.applet.Applet#destroy()
* @see java.applet.Applet#init()
* @see java.applet.Applet#stop()
*/
public void start() {}
/**
* Called by the browser or applet viewer to inform
* this applet that it should stop its execution. It is called when
* the Web page that contains this applet has been replaced by
* another page, and also just before the applet is to be destroyed.
* <p>
* A subclass of <code>Applet</code> should override this method if
* it has any operation that it wants to perform each time the Web
* page containing it is no longer visible. For example, an applet
* with animation might want to use the <code>start</code> method to
* resume animation, and the <code>stop</code> method to suspend the
* animation.
* <p>
* The implementation of this method provided by the
* <code>Applet</code> class does nothing.
*
* @see java.applet.Applet#destroy()
* @see java.applet.Applet#init()
*/
public void stop() {}
/**
* Called by the browser or applet viewer to inform
* this applet that it is being reclaimed and that it should destroy
* any resources that it has allocated. The <code>stop</code> method
* will always be called before <code>destroy</code>.
* <p>
* A subclass of <code>Applet</code> should override this method if
* it has any operation that it wants to perform before it is
* destroyed. For example, an applet with threads would use the
* <code>init</code> method to create the threads and the
* <code>destroy</code> method to kill them.
* <p>
* The implementation of this method provided by the
* <code>Applet</code> class does nothing.
*
* @see java.applet.Applet#init()
* @see java.applet.Applet#start()
* @see java.applet.Applet#stop()
*/
public void destroy() {}
}