/*

 * Copyright (c) 1995, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 in the LICENSE file that

 * accompanied this code).

 *

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.applet;

import java.awt.AWTPermission;

import java.awt.Dimension;

import java.awt.GraphicsEnvironment;

import java.awt.HeadlessException;

import java.awt.Image;

import java.awt.Panel;

import java.awt.event.ComponentEvent;

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 com.sun.media.sound.JavaSoundAudioClip;

/**

 * 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} 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} class provides a standard interface between applets and their

 * environment.

 *

 * @author Arthur van Hoff

 * @author Chris Warth

 * @since 1.0

 * @deprecated The Applet API is deprecated, no replacement.

 */

@Deprecated(since = "9")

public class Applet extends Panel {

    /**

     * Constructs a new Applet.

     * <p>

     * Note: Many methods in {@code java.applet.Applet} may be invoked by the

     * applet only after the applet is fully constructed; applet should avoid

     * calling methods in {@code java.applet.Applet} in the constructor.

     *

     * @throws HeadlessException if {@code GraphicsEnvironment.isHeadless()}

     *         returns {@code true}

     * @see java.awt.GraphicsEnvironment#isHeadless

     * @since 1.4

     */

    public Applet() throws HeadlessException {

        if (GraphicsEnvironment.isHeadless()) {

            throw new HeadlessException();

        }

    }

    /**

     * Applets can be serialized but the following conventions MUST be followed:

     * <p>

     * Before Serialization: An applet must be in STOPPED state.

     * <p>

     * 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.

     */

    private transient AppletStub stub;

    /**

     * Use serialVersionUID from JDK 1.0 for interoperability.

     */

    private static final long serialVersionUID = -5836846270535785031L;

    /**

     * Read an applet from an object input stream.

     *

     * @param  s an object input stream

     * @throws HeadlessException if {@code GraphicsEnvironment.isHeadless()}

     *         returns {@code true}

     * @serial

     * @see java.awt.GraphicsEnvironment#isHeadless

     * @since 1.4

     */

    private void readObject(ObjectInputStream s)

        throws ClassNotFoundException, IOException, HeadlessException {

        if (GraphicsEnvironment.isHeadless()) {

            throw new HeadlessException();

        }

        s.defaultReadObject();

    }

    /**

     * Sets this applet's stub. This is done automatically by the system.

     * <p>

     * If there is a security manager, its {@code checkPermission} method is

     * called with the {@code AWTPermission("setAppletStub")} permission if a

     * stub has already been set.

     *

     * @param  stub the new stub

     * @throws SecurityException if the caller cannot set the stub

     */

    public final void setStub(AppletStub stub) {

        if (this.stub != null) {

            SecurityManager s = System.getSecurityManager();

            if (s != null) {

                s.checkPermission(new AWTPermission("setAppletStub"));

            }

        }

        this.stub = stub;

    }

    /**

     * Determines if this applet is active. An applet is marked active just

     * before its {@code start} method is called. It becomes inactive just

     * before its {@code stop} method is called.

     *

     * @return {@code true} if the applet is active; {@code false} 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;

        }

    }

    /**

     * Gets the {@code URL} of the document in which this applet is embedded.

     * For example, suppose an applet is contained within the document:

     * <blockquote><pre>

     *    http://www.oracle.com/technetwork/java/index.html

     * </pre></blockquote>

     * The document base is:

     * <blockquote><pre>

     *    http://www.oracle.com/technetwork/java/index.html

     * </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 {@code URL}. This is the {@code URL} of the directory which

     * contains this applet.

     *

     * @return the base {@link java.net.URL} of the directory which contains

     *         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")} returns the value

     * {@code "blue"}.

     * <p>

     * The {@code name} argument is case insensitive.

     *

     * @param  name a parameter name

     * @return the value of the named parameter, or {@code null} 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

     */

    @SuppressWarnings("deprecation")

    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

     */

    @SuppressWarnings("deprecation")

    public void resize(Dimension d) {

        resize(d.width, d.height);

    }

    /**

     * Indicates if this container is a validate root.

     * <p>

     * {@code Applet} objects are the validate roots, and, therefore, they

     * override this method to return {@code true}.

     *

     * @return {@code true}

     * @see java.awt.Container#isValidateRoot

     * @since 1.7

     */

    @Override

    public boolean isValidateRoot() {

        return true;

    }

    /**

     * 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} object that can then be painted on the screen.

     * The {@code url} that is passed as an argument must specify an absolute

     * {@code 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 {@code URL} giving the location of the image

     * @return the image at the specified {@code URL}

     * @see java.awt.Image

     */

    public Image getImage(URL url) {

        return getAppletContext().getImage(url);

    }

    /**

     * Returns an {@code Image} object that can then be painted on the screen.

     * The {@code url} argument must specify an absolute {@code URL}. The

     * {@code name} argument is a specifier that is relative to the {@code url}

     * 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}

     *         argument

     * @return the image at the specified {@code URL}

     * @see java.awt.Image

     */

    public Image getImage(URL url, String name) {

        try {

            return getImage(new URL(url, name));

        } catch (MalformedURLException e) {

            return null;

        }

    }

    /**

     * Get an audio clip from the given {@code URL}.

     *

     * @param  url points to the audio clip

     * @return the audio clip at the specified {@code URL}

     * @since 1.2

     */

    public static final AudioClip newAudioClip(URL url) {

        return JavaSoundAudioClip.create(url);

    }

    /**

     * Returns the {@code AudioClip} object specified by the {@code URL}

     * 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 {@code URL} giving the location of the audio clip

     * @return the audio clip at the specified {@code URL}

     * @see java.applet.AudioClip

     */

    public AudioClip getAudioClip(URL url) {

        return getAppletContext().getAudioClip(url);

    }

    /**

     * Returns the {@code AudioClip} object specified by the {@code URL} and

     * {@code name} 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 {@code URL} giving the base location of the audio

     *         clip

     * @param  name the location of the audio clip, relative to the {@code url}

     *         argument

     * @return the audio clip at the specified {@code 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} containing information about the

     * author, version, and copyright of the applet.

     * <p>

     * The implementation of this method provided by the {@code Applet} class

     * returns {@code null}.

     *

     * @return a string containing information about the author, version, and

     *         copyright of the applet

     */

    public String getAppletInfo() {

        return null;

    }

    /**

     * Gets the locale of the applet. It allows the applet to maintain its own

     * locale separated from the locale of the browser or appletviewer.

     *

     * @return the locale of the applet; if no locale has been set, the default

     *         locale is returned

     * @since 1.1

     */

    public Locale getLocale() {

        Locale locale = super.getLocale();

        if (locale == null) {

            return Locale.getDefault();

        }

        return locale;

    }

    /**

     * Returns information about the parameters that are understood by this

     * applet. An applet should override this method to return an array of

     * strings describing these parameters.

     * <p>

     * Each element of the array should be a set of three strings containing the

     * name, the type, and a description. For example:

     * <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} class

     * returns {@code null}.

     *

     * @return an array describing the parameters this applet looks for

     */

    public String[][] getParameterInfo() {

        return null;

    }

    /**

     * Plays the audio clip at the specified absolute {@code URL}. Nothing

     * happens if the audio clip cannot be found.

     *

     * @param  url an absolute {@code 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 {@code URL} and a specifier that is

     * relative to it. Nothing happens if the audio clip cannot be found.

     *

     * @param  url an absolute {@code URL} giving the base location of the audio

     *         clip

     * @param  name the location of the audio clip, relative to the {@code url}

     *         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} method is called.

     * <p>

     * A subclass of {@code Applet} should override this method if it has

     * initialization to perform. For example, an applet with threads would use

     * the {@code init} method to create the threads and the {@code destroy}

     * method to kill them.

     * <p>

     * The implementation of this method provided by the {@code Applet} 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} method

     * and each time the applet is revisited in a Web page.

     * <p>

     * A subclass of {@code Applet} 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} method to resume animation, and the {@code stop} method to

     * suspend the animation.

     * <p>

     * Note: some methods, such as {@code getLocationOnScreen}, can only provide

     * meaningful results if the applet is showing. Because {@code isShowing}

     * returns {@code false} when the applet's {@code start} is first called,

     * methods requiring {@code isShowing} to return {@code true} should be

     * called from a {@code ComponentListener}.

     * <p>

     * The implementation of this method provided by the {@code Applet} class

     * does nothing.

     *

     * @see java.applet.Applet#destroy()

     * @see java.applet.Applet#init()

     * @see java.applet.Applet#stop()

     * @see java.awt.Component#isShowing()

     * @see java.awt.event.ComponentListener#componentShown(ComponentEvent)

     */

    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.