/*
 * Copyright (c) 1995, 2021, 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.awt;

import java.awt.datatransfer.Clipboard;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragGestureRecognizer;
import java.awt.dnd.DragSource;
import java.awt.event.AWTEventListener;
import java.awt.event.AWTEventListenerProxy;
import java.awt.event.ActionEvent;
import java.awt.event.AdjustmentEvent;
import java.awt.event.ComponentEvent;
import java.awt.event.ContainerEvent;
import java.awt.event.FocusEvent;
import java.awt.event.HierarchyEvent;
import java.awt.event.InputEvent;
import java.awt.event.InputMethodEvent;
import java.awt.event.InvocationEvent;
import java.awt.event.ItemEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.PaintEvent;
import java.awt.event.TextEvent;
import java.awt.event.WindowEvent;
import java.awt.im.InputMethodHighlight;
import java.awt.image.ColorModel;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.io.File;
import java.io.FileInputStream;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.EventListener;
import java.util.HashMap;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.ServiceLoader;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.stream.Collectors;

import javax.accessibility.AccessibilityProvider;

import sun.awt.AWTAccessor;
import sun.awt.AWTPermissions;
import sun.awt.AppContext;
import sun.awt.HeadlessToolkit;
import sun.awt.PeerEvent;
import sun.awt.PlatformGraphicsInfo;
import sun.awt.SunToolkit;

/**
 * This class is the abstract superclass of all actual
 * implementations of the Abstract Window Toolkit. Subclasses of
 * the {@code Toolkit} class are used to bind the various components
 * to particular native toolkit implementations.
 * <p>
 * Many GUI events may be delivered to user
 * asynchronously, if the opposite is not specified explicitly.
 * As well as
 * many GUI operations may be performed asynchronously.
 * This fact means that if the state of a component is set, and then
 * the state immediately queried, the returned value may not yet
 * reflect the requested change.  This behavior includes, but is not
 * limited to:
 * <ul>
 * <li>Scrolling to a specified position.
 * <br>For example, calling {@code ScrollPane.setScrollPosition}
 *     and then {@code getScrollPosition} may return an incorrect
 *     value if the original request has not yet been processed.
 *
 * <li>Moving the focus from one component to another.
 * <br>For more information, see
 * <a href="https://docs.oracle.com/javase/tutorial/uiswing/misc/focus.html#transferTiming">Timing
 * Focus Transfers</a>, a section in
 * <a href="https://docs.oracle.com/javase/tutorial/uiswing/">The Swing
 * Tutorial</a>.
 *
 * <li>Making a top-level container visible.
 * <br>Calling {@code setVisible(true)} on a {@code Window},
 *     {@code Frame} or {@code Dialog} may occur
 *     asynchronously.
 *
 * <li>Setting the size or location of a top-level container.
 * <br>Calls to {@code setSize}, {@code setBounds} or
 *     {@code setLocation} on a {@code Window},
 *     {@code Frame} or {@code Dialog} are forwarded
 *     to the underlying window management system and may be
 *     ignored or modified.  See {@link java.awt.Window} for
 *     more information.
 * </ul>
 * <p>
 * Most applications should not call any of the methods in this
 * class directly. The methods defined by {@code Toolkit} are
 * the "glue" that joins the platform-independent classes in the
 * {@code java.awt} package with their counterparts in
 * {@code java.awt.peer}. Some methods defined by
 * {@code Toolkit} query the native operating system directly.
 *
 * @author      Sami Shaio
 * @author      Arthur van Hoff
 * @author      Fred Ecks
 * @since       1.0
 */
public abstract class Toolkit {

    /**
     * Constructs a {@code Toolkit}.
     */
    protected Toolkit() {}

    // The following method is called by the private method
    // <code>updateSystemColors</code> in <code>SystemColor</code>.

    /**
     * Fills in the integer array that is supplied as an argument
     * with the current system color values.
     *
     * @param     systemColors an integer array.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.1
     */
    protected void loadSystemColors(int[] systemColors)
        throws HeadlessException {
        GraphicsEnvironment.checkHeadless();
    }

    /**
     * Controls whether the layout of Containers is validated dynamically
     * during resizing, or statically, after resizing is complete.
     * Use {@code isDynamicLayoutActive()} to detect if this feature enabled
     * in this program and is supported by this operating system
     * and/or window manager.
     * Note that this feature is supported not on all platforms, and
     * conversely, that this feature cannot be turned off on some platforms.
     * On these platforms where dynamic layout during resizing is not supported
     * (or is always supported), setting this property has no effect.
     * Note that this feature can be set or unset as a property of the
     * operating system or window manager on some platforms.  On such
     * platforms, the dynamic resize property must be set at the operating
     * system or window manager level before this method can take effect.
     * This method does not change support or settings of the underlying
     * operating system or
     * window manager.  The OS/WM support can be
     * queried using getDesktopProperty("awt.dynamicLayoutSupported") method.
     *
     * @param     dynamic  If true, Containers should re-layout their
     *            components as the Container is being resized.  If false,
     *            the layout will be validated after resizing is completed.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     *            returns true
     * @see       #isDynamicLayoutSet()
     * @see       #isDynamicLayoutActive()
     * @see       #getDesktopProperty(String propertyName)
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.4
     */
    public void setDynamicLayout(final boolean dynamic)
        throws HeadlessException {
        GraphicsEnvironment.checkHeadless();
        if (this != getDefaultToolkit()) {
            getDefaultToolkit().setDynamicLayout(dynamic);
        }
    }

    /**
     * Returns whether the layout of Containers is validated dynamically
     * during resizing, or statically, after resizing is complete.
     * Note: this method returns the value that was set programmatically;
     * it does not reflect support at the level of the operating system
     * or window manager for dynamic layout on resizing, or the current
     * operating system or window manager settings.  The OS/WM support can
     * be queried using getDesktopProperty("awt.dynamicLayoutSupported").
     *
     * @return    true if validation of Containers is done dynamically,
     *            false if validation is done after resizing is finished.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     *            returns true
     * @see       #setDynamicLayout(boolean dynamic)
     * @see       #isDynamicLayoutActive()
     * @see       #getDesktopProperty(String propertyName)
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.4
     */
    protected boolean isDynamicLayoutSet()
        throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().isDynamicLayoutSet();
        } else {
            return false;
        }
    }

    /**
     * Returns whether dynamic layout of Containers on resize is currently
     * enabled on the underlying operating system and/or window manager. If the
     * platform supports it, {@code setDynamicLayout(boolean)} may be used to
     * programmatically enable or disable platform dynamic layout. Regardless of
     * whether that toggling is supported, or whether {@code true} or {@code
     * false} is specified as an argument, or has never been called at all, this
     * method will return the active current platform behavior and which will be
     * followed by the JDK in determining layout policy during resizing.
     * <p>
     * If dynamic layout is currently inactive then Containers re-layout their
     * components when resizing is completed. As a result the
     * {@code Component.validate()} method will be invoked only once per resize.
     * If dynamic layout is currently active then Containers re-layout their
     * components on every native resize event and the {@code validate()} method
     * will be invoked each time. The OS/WM support can be queried using the
     * getDesktopProperty("awt.dynamicLayoutSupported") method. This property
     * will reflect the platform capability but is not sufficient to tell if it
     * is presently enabled.
     *
     * @return true if dynamic layout of Containers on resize is currently
     *         active, false otherwise.
     * @throws HeadlessException if the GraphicsEnvironment.isHeadless() method
     *         returns true
     * @see #setDynamicLayout(boolean dynamic)
     * @see #isDynamicLayoutSet()
     * @see #getDesktopProperty(String propertyName)
     * @see java.awt.GraphicsEnvironment#isHeadless
     * @since 1.4
     */
    public boolean isDynamicLayoutActive()
        throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().isDynamicLayoutActive();
        } else {
            return false;
        }
    }

    /**
     * Gets the size of the screen.  On systems with multiple displays, the
     * primary display is used.  Multi-screen aware display dimensions are
     * available from {@code GraphicsConfiguration} and
     * {@code GraphicsDevice}.
     * @return    the size of this toolkit's screen, in pixels.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsConfiguration#getBounds
     * @see       java.awt.GraphicsDevice#getDisplayMode
     * @see       java.awt.GraphicsEnvironment#isHeadless
     */
    public abstract Dimension getScreenSize()
        throws HeadlessException;

    /**
     * Returns the screen resolution in dots-per-inch.
     * @return    this toolkit's screen resolution, in dots-per-inch.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     */
    public abstract int getScreenResolution()
        throws HeadlessException;

    /**
     * Gets the insets of the screen.
     * @param     gc a {@code GraphicsConfiguration}
     * @return    the insets of this toolkit's screen, in pixels.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.4
     */
    public Insets getScreenInsets(GraphicsConfiguration gc)
        throws HeadlessException {
        GraphicsEnvironment.checkHeadless();
        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().getScreenInsets(gc);
        } else {
            return new Insets(0, 0, 0, 0);
        }
    }

    /**
     * Determines the color model of this toolkit's screen.
     * <p>
     * {@code ColorModel} is an abstract class that
     * encapsulates the ability to translate between the
     * pixel values of an image and its red, green, blue,
     * and alpha components.
     * <p>
     * This toolkit method is called by the
     * {@code getColorModel} method
     * of the {@code Component} class.
     * @return    the color model of this toolkit's screen.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @see       java.awt.image.ColorModel
     * @see       java.awt.Component#getColorModel
     */
    public abstract ColorModel getColorModel()
        throws HeadlessException;

    /**
     * Returns the names of the available fonts in this toolkit.<p>
     * For 1.1, the following font names are deprecated (the replacement
     * name follows):
     * <ul>
     * <li>TimesRoman (use Serif)
     * <li>Helvetica (use SansSerif)
     * <li>Courier (use Monospaced)
     * </ul><p>
     * The ZapfDingbats fontname is also deprecated in 1.1 but the characters
     * are defined in Unicode starting at 0x2700, and as of 1.1 Java supports
     * those characters.
     * @return    the names of the available fonts in this toolkit.
     * @deprecated see {@link java.awt.GraphicsEnvironment#getAvailableFontFamilyNames()}
     * @see java.awt.GraphicsEnvironment#getAvailableFontFamilyNames()
     */
    @Deprecated
    public abstract String[] getFontList();

    /**
     * Gets the screen device metrics for rendering of the font.
     * @param     font   a font
     * @return    the screen metrics of the specified font in this toolkit
     * @deprecated  As of JDK version 1.2, replaced by the {@code Font}
     *          method {@code getLineMetrics}.
     * @see java.awt.font.LineMetrics
     * @see java.awt.Font#getLineMetrics
     * @see java.awt.GraphicsEnvironment#getScreenDevices
     */
    @Deprecated
    public abstract FontMetrics getFontMetrics(Font font);

    /**
     * Synchronizes this toolkit's graphics state. Some window systems
     * may do buffering of graphics events.
     * <p>
     * This method ensures that the display is up-to-date. It is useful
     * for animation.
     */
    public abstract void sync();

    /**
     * The default toolkit.
     */
    private static Toolkit toolkit;

    /**
     * Used internally by the assistive technologies functions; set at
     * init time and used at load time
     */
    private static String atNames;

    /**
     * Initializes properties related to assistive technologies.
     * These properties are used both in the loadAssistiveProperties()
     * function below, as well as other classes in the jdk that depend
     * on the properties (such as the use of the screen_magnifier_present
     * property in Java2D hardware acceleration initialization).  The
     * initialization of the properties must be done before the platform-
     * specific Toolkit class is instantiated so that all necessary
     * properties are set up properly before any classes dependent upon them
     * are initialized.
     */
    @SuppressWarnings("removal")
    private static void initAssistiveTechnologies() {

        // Get accessibility properties
        final String sep = File.separator;
        final Properties properties = new Properties();


        atNames = java.security.AccessController.doPrivileged(
            new java.security.PrivilegedAction<String>() {
            public String run() {

                // Try loading the per-user accessibility properties file.
                try {
                    File propsFile = new File(
                      System.getProperty("user.home") +
                      sep + ".accessibility.properties");
                    try (FileInputStream in = new FileInputStream(propsFile)) {
                        // Inputstream has been buffered in Properties class
                        properties.load(in);
                    }
                } catch (Exception e) {
                    // Per-user accessibility properties file does not exist
                }

                // Try loading the system-wide accessibility properties
                // file only if a per-user accessibility properties
                // file does not exist or is empty.
                if (properties.size() == 0) {
                    try {
                        File propsFile = new File(
                            System.getProperty("java.home") + sep + "conf" +
                            sep + "accessibility.properties");
                        try (FileInputStream in = new FileInputStream(propsFile)) {
                            // Inputstream has been buffered in Properties class
                            properties.load(in);
                        }
                    } catch (Exception e) {
                        // System-wide accessibility properties file does
                        // not exist;
                    }
                }

                // Get whether a screen magnifier is present.  First check
                // the system property and then check the properties file.
                String magPresent = System.getProperty("javax.accessibility.screen_magnifier_present");
                if (magPresent == null) {
                    magPresent = properties.getProperty("screen_magnifier_present", null);
                    if (magPresent != null) {
                        System.setProperty("javax.accessibility.screen_magnifier_present", magPresent);
                    }
                }

                // Get the names of any assistive technologies to load.  First
                // check the system property and then check the properties
                // file.
                String classNames = System.getProperty("javax.accessibility.assistive_technologies");
                if (classNames == null) {
                    classNames = properties.getProperty("assistive_technologies", null);
                    if (classNames != null) {
                        System.setProperty("javax.accessibility.assistive_technologies", classNames);
                    }
                }
                return classNames;
            }
        });
    }

    /**
     * Rethrow the AWTError but include the cause.
     *
     * @param s the error message
     * @param e the original exception
     * @throws AWTError the new AWTError including the cause (the original exception)
     */
    private static void newAWTError(Throwable e, String s) {
        AWTError newAWTError = new AWTError(s);
        newAWTError.initCause(e);
        throw newAWTError;
    }

    /**
     * When a service provider for Assistive Technology is not found look for a
     * supporting class on the class path and instantiate it.
     *
     * @param atName the name of the class to be loaded
     */
    private static void fallbackToLoadClassForAT(String atName) {
        try {
            Class<?> c = Class.forName(atName, false, ClassLoader.getSystemClassLoader());
            c.getConstructor().newInstance();
        } catch (ClassNotFoundException e) {
            newAWTError(e, "Assistive Technology not found: " + atName);
        } catch (InstantiationException e) {
            newAWTError(e, "Could not instantiate Assistive Technology: " + atName);
        } catch (IllegalAccessException e) {
            newAWTError(e, "Could not access Assistive Technology: " + atName);
        } catch (Exception e) {
            newAWTError(e, "Error trying to install Assistive Technology: " + atName);
        }
    }

    /**
     * Loads accessibility support using the property assistive_technologies.
     * The form is assistive_technologies= followed by a comma-separated list of
     * assistive technology providers to load.  The order in which providers are
     * loaded is determined by the order in which the ServiceLoader discovers
     * implementations of the AccessibilityProvider interface, not by the order
     * of provider names in the property list.  When a provider is found its
     * accessibility implementation will be started by calling the provider's
     * activate method. If the list of assistive technology providers is the
     * empty string or contains only
     * {@linkplain Character#isWhitespace(int) white space} characters or
     * {@code null} it is ignored. All other errors are handled via an AWTError
     * exception.
     */
    @SuppressWarnings("removal")
    private static void loadAssistiveTechnologies() {
        // Load any assistive technologies
        if (atNames != null && !atNames.isBlank()) {
            ClassLoader cl = ClassLoader.getSystemClassLoader();
            Set<String> names = Arrays.stream(atNames.split(","))
                                      .map(String::trim)
                                      .collect(Collectors.toSet());
            final Map<String, AccessibilityProvider> providers = new HashMap<>();
            AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
                try {
                    for (AccessibilityProvider p : ServiceLoader.load(AccessibilityProvider.class, cl)) {
                        String name = p.getName();
                        if (names.contains(name) && !providers.containsKey(name)) {
                            p.activate();
                            providers.put(name, p);
                        }
                    }
                } catch (java.util.ServiceConfigurationError | Exception e) {
                    newAWTError(e, "Could not load or activate service provider");
                }
                return null;
            });
            names.stream()
                 .filter(n -> !providers.containsKey(n))
                 .forEach(Toolkit::fallbackToLoadClassForAT);
        }
    }

    /**
     * Gets the default toolkit.
     * <p>
     * If a system property named {@code "java.awt.headless"} is set
     * to {@code true} then the headless implementation
     * of {@code Toolkit} is used,
     * otherwise the default platform-specific implementation of
     * {@code Toolkit} is used.
     * <p>
     * If this Toolkit is not a headless implementation and if they exist, service
     * providers of {@link javax.accessibility.AccessibilityProvider} will be loaded
     * if specified by the system property
     * {@code javax.accessibility.assistive_technologies}.
     * <p>
     * An example of setting this property is to invoke Java with
     * {@code -Djavax.accessibility.assistive_technologies=MyServiceProvider}.
     * In addition to MyServiceProvider other service providers can be specified
     * using a comma separated list.  Service providers are loaded after the AWT
     * toolkit is created.
     * <p>
     * If the list of assistive technology providers as provided through system
     * property "{@systemProperty javax.accessibility.assistive_technologies}"
     * is the empty string or contains only
     * {@linkplain Character#isWhitespace(int) white space} characters it is
     * ignored. All other errors are handled via an AWTError exception.
     * <p>
     * The names specified in the assistive_technologies property are used to query
     * each service provider implementation.  If the requested name matches the
     * {@linkplain AccessibilityProvider#getName name} of the service provider, the
     * {@link AccessibilityProvider#activate} method will be invoked to activate the
     * matching service provider.
     *
     * @implSpec
     * If assistive technology service providers are not specified with a system
     * property this implementation will look in a properties file located as follows:
     * <ul>
     * <li> {@code ${user.home}/.accessibility.properties}
     * <li> {@code ${java.home}/conf/accessibility.properties}
     * </ul>
     * Only the first of these files to be located will be consulted.  The requested
     * service providers are specified by setting the {@code assistive_technologies=}
     * property.  A single provider or a comma separated list of providers can be
     * specified.
     *
     * @return     the default toolkit.
     * @throws  AWTError in case of an error loading assistive technologies.
     * @see java.util.ServiceLoader
     * @see javax.accessibility.AccessibilityProvider
     */
    public static synchronized Toolkit getDefaultToolkit() {
        if (toolkit == null) {
            toolkit = PlatformGraphicsInfo.createToolkit();
            if (GraphicsEnvironment.isHeadless() &&
                !(toolkit instanceof HeadlessToolkit)) {
                toolkit = new HeadlessToolkit(toolkit);
            }
            if (!GraphicsEnvironment.isHeadless()) {
                loadAssistiveTechnologies();
            }
        }
        return toolkit;
    }

    /**
     * Returns an image which gets pixel data from the specified file,
     * whose format can be either GIF, JPEG or PNG.
     * The underlying toolkit attempts to resolve multiple requests
     * with the same filename to the same returned Image.
     * <p>
     * Since the mechanism required to facilitate this sharing of
     * {@code Image} objects may continue to hold onto images
     * that are no longer in use for an indefinite period of time,
     * developers are encouraged to implement their own caching of
     * images by using the {@link #createImage(java.lang.String) createImage}
     * variant wherever available.
     * If the image data contained in the specified file changes,
     * the {@code Image} object returned from this method may
     * still contain stale information which was loaded from the
     * file after a prior call.
     * Previously loaded image data can be manually discarded by
     * calling the {@link Image#flush flush} method on the
     * returned {@code Image}.
     * <p>
     * This method first checks if there is a security manager installed.
     * If so, the method calls the security manager's
     * {@code checkRead} method with the file specified to ensure
     * that the access to the image is allowed.
     * @param     filename   the name of a file containing pixel data
     *                         in a recognized file format.
     * @return    an image which gets its pixel data from
     *                         the specified file.
     * @throws SecurityException  if a security manager exists and its
     *                            checkRead method doesn't allow the operation.
     * @see #createImage(java.lang.String)
     */
    public abstract Image getImage(String filename);

    /**
     * Returns an image which gets pixel data from the specified URL.
     * The pixel data referenced by the specified URL must be in one
     * of the following formats: GIF, JPEG or PNG.
     * The underlying toolkit attempts to resolve multiple requests
     * with the same URL to the same returned Image.
     * <p>
     * Since the mechanism required to facilitate this sharing of
     * {@code Image} objects may continue to hold onto images
     * that are no longer in use for an indefinite period of time,
     * developers are encouraged to implement their own caching of
     * images by using the {@link #createImage(java.net.URL) createImage}
     * variant wherever available.
     * If the image data stored at the specified URL changes,
     * the {@code Image} object returned from this method may
     * still contain stale information which was fetched from the
     * URL after a prior call.
     * Previously loaded image data can be manually discarded by
     * calling the {@link Image#flush flush} method on the
     * returned {@code Image}.
     * <p>
     * This method first checks if there is a security manager installed.
     * If so, the method calls the security manager's
     * {@code checkPermission} method with the corresponding
     * permission to ensure that the access to the image is allowed.
     * If the connection to the specified URL requires
     * either {@code URLPermission} or {@code SocketPermission},
     * then {@code URLPermission} is used for security checks.
     * @param     url   the URL to use in fetching the pixel data.
     * @return    an image which gets its pixel data from
     *                         the specified URL.
     * @throws SecurityException  if a security manager exists and its
     *                            checkPermission method doesn't allow
     *                            the operation.
     * @see #createImage(java.net.URL)
     */
    public abstract Image getImage(URL url);

    /**
     * Returns an image which gets pixel data from the specified file.
     * The returned Image is a new object which will not be shared
     * with any other caller of this method or its getImage variant.
     * <p>
     * This method first checks if there is a security manager installed.
     * If so, the method calls the security manager's
     * {@code checkRead} method with the specified file to ensure
     * that the image creation is allowed.
     * @param     filename   the name of a file containing pixel data
     *                         in a recognized file format.
     * @return    an image which gets its pixel data from
     *                         the specified file.
     * @throws SecurityException  if a security manager exists and its
     *                            checkRead method doesn't allow the operation.
     * @see #getImage(java.lang.String)
     */
    public abstract Image createImage(String filename);

    /**
     * Returns an image which gets pixel data from the specified URL.
     * The returned Image is a new object which will not be shared
     * with any other caller of this method or its getImage variant.
     * <p>
     * This method first checks if there is a security manager installed.
     * If so, the method calls the security manager's
     * {@code checkPermission} method with the corresponding
     * permission to ensure that the image creation is allowed.
     * If the connection to the specified URL requires
     * either {@code URLPermission} or {@code SocketPermission},
     * then {@code URLPermission} is used for security checks.
     * @param     url   the URL to use in fetching the pixel data.
     * @return    an image which gets its pixel data from
     *                         the specified URL.
     * @throws SecurityException  if a security manager exists and its
     *                            checkPermission method doesn't allow
     *                            the operation.
     * @see #getImage(java.net.URL)
     */
    public abstract Image createImage(URL url);

    /**
     * Prepares an image for rendering.
     * <p>
     * If the values of the width and height arguments are both
     * {@code -1}, this method prepares the image for rendering
     * on the default screen; otherwise, this method prepares an image
     * for rendering on the default screen at the specified width and height.
     * <p>
     * The image data is downloaded asynchronously in another thread,
     * and an appropriately scaled screen representation of the image is
     * generated.
     * <p>
     * This method is called by components {@code prepareImage}
     * methods.
     * <p>
     * Information on the flags returned by this method can be found
     * with the definition of the {@code ImageObserver} interface.

     * @param     image      the image for which to prepare a
     *                           screen representation.
     * @param     width      the width of the desired screen
     *                           representation, or {@code -1}.
     * @param     height     the height of the desired screen
     *                           representation, or {@code -1}.
     * @param     observer   the {@code ImageObserver}
     *                           object to be notified as the
     *                           image is being prepared.
     * @return    {@code true} if the image has already been
     *                 fully prepared; {@code false} otherwise.
     * @see       java.awt.Component#prepareImage(java.awt.Image,
     *                 java.awt.image.ImageObserver)
     * @see       java.awt.Component#prepareImage(java.awt.Image,
     *                 int, int, java.awt.image.ImageObserver)
     * @see       java.awt.image.ImageObserver
     */
    public abstract boolean prepareImage(Image image, int width, int height,
                                         ImageObserver observer);

    /**
     * Indicates the construction status of a specified image that is
     * being prepared for display.
     * <p>
     * If the values of the width and height arguments are both
     * {@code -1}, this method returns the construction status of
     * a screen representation of the specified image in this toolkit.
     * Otherwise, this method returns the construction status of a
     * scaled representation of the image at the specified width
     * and height.
     * <p>
     * This method does not cause the image to begin loading.
     * An application must call {@code prepareImage} to force
     * the loading of an image.
     * <p>
     * This method is called by the component's {@code checkImage}
     * methods.
     * <p>
     * Information on the flags returned by this method can be found
     * with the definition of the {@code ImageObserver} interface.
     * @param     image   the image whose status is being checked.
     * @param     width   the width of the scaled version whose status is
     *                 being checked, or {@code -1}.
     * @param     height  the height of the scaled version whose status
     *                 is being checked, or {@code -1}.
     * @param     observer   the {@code ImageObserver} object to be
     *                 notified as the image is being prepared.
     * @return    the bitwise inclusive <strong>OR</strong> of the
     *                 {@code ImageObserver} flags for the
     *                 image data that is currently available.
     * @see       java.awt.Toolkit#prepareImage(java.awt.Image,
     *                 int, int, java.awt.image.ImageObserver)
     * @see       java.awt.Component#checkImage(java.awt.Image,
     *                 java.awt.image.ImageObserver)
     * @see       java.awt.Component#checkImage(java.awt.Image,
     *                 int, int, java.awt.image.ImageObserver)
     * @see       java.awt.image.ImageObserver
     */
    public abstract int checkImage(Image image, int width, int height,
                                   ImageObserver observer);

    /**
     * Creates an image with the specified image producer.
     * @param     producer the image producer to be used.
     * @return    an image with the specified image producer.
     * @see       java.awt.Image
     * @see       java.awt.image.ImageProducer
     * @see       java.awt.Component#createImage(java.awt.image.ImageProducer)
     */
    public abstract Image createImage(ImageProducer producer);

    /**
     * Creates an image which decodes the image stored in the specified
     * byte array.
     * <p>
     * The data must be in some image format, such as GIF or JPEG,
     * that is supported by this toolkit.
     * @param     imagedata   an array of bytes, representing
     *                         image data in a supported image format.
     * @return    an image.
     * @since     1.1
     */
    public Image createImage(byte[] imagedata) {
        return createImage(imagedata, 0, imagedata.length);
    }

    /**
     * Creates an image which decodes the image stored in the specified
     * byte array, and at the specified offset and length.
     * The data must be in some image format, such as GIF or JPEG,
     * that is supported by this toolkit.
     * @param     imagedata   an array of bytes, representing
     *                         image data in a supported image format.
     * @param     imageoffset  the offset of the beginning
     *                         of the data in the array.
     * @param     imagelength  the length of the data in the array.
     * @return    an image.
     * @since     1.1
     */
    public abstract Image createImage(byte[] imagedata,
                                      int imageoffset,
                                      int imagelength);

    /**
     * Gets a {@code PrintJob} object which is the result of initiating
     * a print operation on the toolkit's platform.
     * <p>
     * Each actual implementation of this method should first check if there
     * is a security manager installed. If there is, the method should call
     * the security manager's {@code checkPrintJobAccess} method to
     * ensure initiation of a print operation is allowed. If the default
     * implementation of {@code checkPrintJobAccess} is used (that is,
     * that method is not overridden), then this results in a call to the
     * security manager's {@code checkPermission} method with a
     * {@code RuntimePermission("queuePrintJob")} permission.
     *
     * @param   frame the parent of the print dialog. May not be null.
     * @param   jobtitle the title of the PrintJob. A null title is equivalent
     *          to "".
     * @param   props a Properties object containing zero or more properties.
     *          Properties are not standardized and are not consistent across
     *          implementations. Because of this, PrintJobs which require job
     *          and page control should use the version of this function which
     *          takes JobAttributes and PageAttributes objects. This object
     *          may be updated to reflect the user's job choices on exit. May
     *          be null.
     * @return  a {@code PrintJob} object, or {@code null} if the
     *          user cancelled the print job.
     * @throws  NullPointerException if frame is null
     * @throws  SecurityException if this thread is not allowed to initiate a
     *          print job request
     * @see     java.awt.GraphicsEnvironment#isHeadless
     * @see     java.awt.PrintJob
     * @see     java.lang.RuntimePermission
     * @since   1.1
     */
    public abstract PrintJob getPrintJob(Frame frame, String jobtitle,
                                         Properties props);

    /**
     * Gets a {@code PrintJob} object which is the result of initiating
     * a print operation on the toolkit's platform.
     * <p>
     * Each actual implementation of this method should first check if there
     * is a security manager installed. If there is, the method should call
     * the security manager's {@code checkPrintJobAccess} method to
     * ensure initiation of a print operation is allowed. If the default
     * implementation of {@code checkPrintJobAccess} is used (that is,
     * that method is not overridden), then this results in a call to the
     * security manager's {@code checkPermission} method with a
     * {@code RuntimePermission("queuePrintJob")} permission.
     *
     * @param   frame the parent of the print dialog. May not be null.
     * @param   jobtitle the title of the PrintJob. A null title is equivalent
     *          to "".
     * @param   jobAttributes a set of job attributes which will control the
     *          PrintJob. The attributes will be updated to reflect the user's
     *          choices as outlined in the JobAttributes documentation. May be
     *          null.
     * @param   pageAttributes a set of page attributes which will control the
     *          PrintJob. The attributes will be applied to every page in the
     *          job. The attributes will be updated to reflect the user's
     *          choices as outlined in the PageAttributes documentation. May be
     *          null.
     * @return  a {@code PrintJob} object, or {@code null} if the
     *          user cancelled the print job.
     * @throws  NullPointerException if frame is null
     * @throws  IllegalArgumentException if pageAttributes specifies differing
     *          cross feed and feed resolutions. Also if this thread has
     *          access to the file system and jobAttributes specifies
     *          print to file, and the specified destination file exists but
     *          is a directory rather than a regular file, does not exist but
     *          cannot be created, or cannot be opened for any other reason.
     *          However in the case of print to file, if a dialog is also
     *          requested to be displayed then the user will be given an
     *          opportunity to select a file and proceed with printing.
     *          The dialog will ensure that the selected output file
     *          is valid before returning from this method.
     * @throws  SecurityException if this thread is not allowed to initiate a
     *          print job request, or if jobAttributes specifies print to file,
     *          and this thread is not allowed to access the file system
     * @see     java.awt.PrintJob
     * @see     java.awt.GraphicsEnvironment#isHeadless
     * @see     java.lang.RuntimePermission
     * @see     java.awt.JobAttributes
     * @see     java.awt.PageAttributes
     * @since   1.3
     */
    public PrintJob getPrintJob(Frame frame, String jobtitle,
                                JobAttributes jobAttributes,
                                PageAttributes pageAttributes) {
        // Override to add printing support with new job/page control classes

        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().getPrintJob(frame, jobtitle,
                                                           jobAttributes,
                                                           pageAttributes);
        } else {
            return getPrintJob(frame, jobtitle, null);
        }
    }

    /**
     * Emits an audio beep depending on native system settings and hardware
     * capabilities.
     * @since     1.1
     */
    public abstract void beep();

    /**
     * Gets the singleton instance of the system Clipboard which interfaces
     * with clipboard facilities provided by the native platform. This
     * clipboard enables data transfer between Java programs and native
     * applications which use native clipboard facilities.
     * <p>
     * In addition to any and all default formats text returned by the system
     * Clipboard's {@code getTransferData()} method is available in the
     * following flavors:
     * <ul>
     * <li>DataFlavor.stringFlavor</li>
     * <li>DataFlavor.plainTextFlavor (<b>deprecated</b>)</li>
     * </ul>
     * As with {@code java.awt.datatransfer.StringSelection}, if the
     * requested flavor is {@code DataFlavor.plainTextFlavor}, or an
     * equivalent flavor, a Reader is returned. <b>Note:</b> The behavior of
     * the system Clipboard's {@code getTransferData()} method for
     * {@code DataFlavor.plainTextFlavor}, and equivalent DataFlavors, is
     * inconsistent with the definition of {@code DataFlavor.plainTextFlavor}.
     * Because of this, support for
     * {@code DataFlavor.plainTextFlavor}, and equivalent flavors, is
     * <b>deprecated</b>.
     * <p>
     * Each actual implementation of this method should first check if there
     * is a security manager installed. If there is, the method should call
     * the security manager's {@link SecurityManager#checkPermission
     * checkPermission} method to check {@code AWTPermission("accessClipboard")}.
     *
     * @return    the system Clipboard
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @see       java.awt.datatransfer.Clipboard
     * @see       java.awt.datatransfer.StringSelection
     * @see       java.awt.datatransfer.DataFlavor#stringFlavor
     * @see       java.awt.datatransfer.DataFlavor#plainTextFlavor
     * @see       java.io.Reader
     * @see       java.awt.AWTPermission
     * @since     1.1
     */
    public abstract Clipboard getSystemClipboard()
        throws HeadlessException;

    /**
     * Gets the singleton instance of the system selection as a
     * {@code Clipboard} object. This allows an application to read and
     * modify the current, system-wide selection.
     * <p>
     * An application is responsible for updating the system selection whenever
     * the user selects text, using either the mouse or the keyboard.
     * Typically, this is implemented by installing a
     * {@code FocusListener} on all {@code Component}s which support
     * text selection, and, between {@code FOCUS_GAINED} and
     * {@code FOCUS_LOST} events delivered to that {@code Component},
     * updating the system selection {@code Clipboard} when the selection
     * changes inside the {@code Component}. Properly updating the system
     * selection ensures that a Java application will interact correctly with
     * native applications and other Java applications running simultaneously
     * on the system. Note that {@code java.awt.TextComponent} and
     * {@code javax.swing.text.JTextComponent} already adhere to this
     * policy. When using these classes, and their subclasses, developers need
     * not write any additional code.
     * <p>
     * Some platforms do not support a system selection {@code Clipboard}.
     * On those platforms, this method will return {@code null}. In such a
     * case, an application is absolved from its responsibility to update the
     * system selection {@code Clipboard} as described above.
     * <p>
     * Each actual implementation of this method should first check if there
     * is a security manager installed. If there is, the method should call
     * the security manager's {@link SecurityManager#checkPermission
     * checkPermission} method to check {@code AWTPermission("accessClipboard")}.
     *
     * @return the system selection as a {@code Clipboard}, or
     *         {@code null} if the native platform does not support a
     *         system selection {@code Clipboard}
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     *            returns true
     *
     * @see java.awt.datatransfer.Clipboard
     * @see java.awt.event.FocusListener
     * @see java.awt.event.FocusEvent#FOCUS_GAINED
     * @see java.awt.event.FocusEvent#FOCUS_LOST
     * @see TextComponent
     * @see javax.swing.text.JTextComponent
     * @see AWTPermission
     * @see GraphicsEnvironment#isHeadless
     * @since 1.4
     */
    public Clipboard getSystemSelection() throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().getSystemSelection();
        } else {
            GraphicsEnvironment.checkHeadless();
            return null;
        }
    }

    /**
     * Determines which modifier key is the appropriate accelerator
     * key for menu shortcuts.
     * <p>
     * Menu shortcuts, which are embodied in the
     * {@code MenuShortcut} class, are handled by the
     * {@code MenuBar} class.
     * <p>
     * By default, this method returns {@code Event.CTRL_MASK}.
     * Toolkit implementations should override this method if the
     * <b>Control</b> key isn't the correct key for accelerators.
     * @return    the modifier mask on the {@code Event} class
     *                 that is used for menu shortcuts on this toolkit.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @see       java.awt.MenuBar
     * @see       java.awt.MenuShortcut
     * @deprecated It is recommended that extended modifier keys and
     *             {@link #getMenuShortcutKeyMaskEx()} be used instead
     * @since     1.1
     */
    @Deprecated(since = "10")
    public int getMenuShortcutKeyMask() throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        return Event.CTRL_MASK;
    }

    /**
     * Determines which extended modifier key is the appropriate accelerator
     * key for menu shortcuts.
     * <p>
     * Menu shortcuts, which are embodied in the {@code MenuShortcut} class, are
     * handled by the {@code MenuBar} class.
     * <p>
     * By default, this method returns {@code InputEvent.CTRL_DOWN_MASK}.
     * Toolkit implementations should override this method if the
     * <b>Control</b> key isn't the correct key for accelerators.
     *
     * @return the modifier mask on the {@code InputEvent} class that is used
     *         for menu shortcuts on this toolkit
     * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns
     *         true
     * @see java.awt.GraphicsEnvironment#isHeadless
     * @see java.awt.MenuBar
     * @see java.awt.MenuShortcut
     * @since 10
     */
    public int getMenuShortcutKeyMaskEx() throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        return InputEvent.CTRL_DOWN_MASK;
    }

    /**
     * Returns whether the given locking key on the keyboard is currently in
     * its "on" state.
     * Valid key codes are
     * {@link java.awt.event.KeyEvent#VK_CAPS_LOCK VK_CAPS_LOCK},
     * {@link java.awt.event.KeyEvent#VK_NUM_LOCK VK_NUM_LOCK},
     * {@link java.awt.event.KeyEvent#VK_SCROLL_LOCK VK_SCROLL_LOCK}, and
     * {@link java.awt.event.KeyEvent#VK_KANA_LOCK VK_KANA_LOCK}.
     *
     * @param  keyCode the key code
     * @return {@code true} if the given key is currently in its "on" state;
     *          otherwise {@code false}
     * @throws java.lang.IllegalArgumentException if {@code keyCode}
     * is not one of the valid key codes
     * @throws java.lang.UnsupportedOperationException if the host system doesn't
     * allow getting the state of this key programmatically, or if the keyboard
     * doesn't have this key
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since 1.3
     */
    public boolean getLockingKeyState(int keyCode)
        throws UnsupportedOperationException
    {
        GraphicsEnvironment.checkHeadless();

        if (! (keyCode == KeyEvent.VK_CAPS_LOCK || keyCode == KeyEvent.VK_NUM_LOCK ||
               keyCode == KeyEvent.VK_SCROLL_LOCK || keyCode == KeyEvent.VK_KANA_LOCK)) {
            throw new IllegalArgumentException("invalid key for Toolkit.getLockingKeyState");
        }
        throw new UnsupportedOperationException("Toolkit.getLockingKeyState");
    }

    /**
     * Sets the state of the given locking key on the keyboard.
     * Valid key codes are
     * {@link java.awt.event.KeyEvent#VK_CAPS_LOCK VK_CAPS_LOCK},
     * {@link java.awt.event.KeyEvent#VK_NUM_LOCK VK_NUM_LOCK},
     * {@link java.awt.event.KeyEvent#VK_SCROLL_LOCK VK_SCROLL_LOCK}, and
     * {@link java.awt.event.KeyEvent#VK_KANA_LOCK VK_KANA_LOCK}.
     * <p>
     * Depending on the platform, setting the state of a locking key may
     * involve event processing and therefore may not be immediately
     * observable through getLockingKeyState.
     *
     * @param  keyCode the key code
     * @param  on the state of the key
     * @throws java.lang.IllegalArgumentException if {@code keyCode}
     * is not one of the valid key codes
     * @throws java.lang.UnsupportedOperationException if the host system doesn't
     * allow setting the state of this key programmatically, or if the keyboard
     * doesn't have this key
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since 1.3
     */
    public void setLockingKeyState(int keyCode, boolean on)
        throws UnsupportedOperationException
    {
        GraphicsEnvironment.checkHeadless();

        if (! (keyCode == KeyEvent.VK_CAPS_LOCK || keyCode == KeyEvent.VK_NUM_LOCK ||
               keyCode == KeyEvent.VK_SCROLL_LOCK || keyCode == KeyEvent.VK_KANA_LOCK)) {
            throw new IllegalArgumentException("invalid key for Toolkit.setLockingKeyState");
        }
        throw new UnsupportedOperationException("Toolkit.setLockingKeyState");
    }

    /**
     * Give native peers the ability to query the native container
     * given a native component (eg the direct parent may be lightweight).
     *
     * @param  c the component to fetch the container for
     * @return the native container object for the component
     */
    protected static Container getNativeContainer(Component c) {
        return c.getNativeContainer();
    }

    /**
     * Creates a new custom cursor object.
     * If the image to display is invalid, the cursor will be hidden (made
     * completely transparent), and the hotspot will be set to (0, 0).
     *
     * <p>Note that multi-frame images are invalid and may cause this
     * method to hang.
     *
     * @param cursor the image to display when the cursor is activated
     * @param hotSpot the X and Y of the large cursor's hot spot; the
     *   hotSpot values must be less than the Dimension returned by
     *   {@code getBestCursorSize}
     * @param     name a localized description of the cursor, for Java Accessibility use
     * @throws IndexOutOfBoundsException if the hotSpot values are outside
     *   the bounds of the cursor
     * @return the cursor created
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.2
     */
    public Cursor createCustomCursor(Image cursor, Point hotSpot, String name)
        throws IndexOutOfBoundsException, HeadlessException
    {
        // Override to implement custom cursor support.
        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().
                createCustomCursor(cursor, hotSpot, name);
        } else {
            return new Cursor(Cursor.DEFAULT_CURSOR);
        }
    }

    /**
     * Returns the supported cursor dimension which is closest to the desired
     * sizes.  Systems which only support a single cursor size will return that
     * size regardless of the desired sizes.  Systems which don't support custom
     * cursors will return a dimension of 0, 0. <p>
     * Note:  if an image is used whose dimensions don't match a supported size
     * (as returned by this method), the Toolkit implementation will attempt to
     * resize the image to a supported size.
     * Since converting low-resolution images is difficult,
     * no guarantees are made as to the quality of a cursor image which isn't a
     * supported size.  It is therefore recommended that this method
     * be called and an appropriate image used so no image conversion is made.
     *
     * @param     preferredWidth the preferred cursor width the component would like
     * to use.
     * @param     preferredHeight the preferred cursor height the component would like
     * to use.
     * @return    the closest matching supported cursor size, or a dimension of 0,0 if
     * the Toolkit implementation doesn't support custom cursors.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.2
     */
    public Dimension getBestCursorSize(int preferredWidth,
        int preferredHeight) throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        // Override to implement custom cursor support.
        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().
                getBestCursorSize(preferredWidth, preferredHeight);
        } else {
            return new Dimension(0, 0);
        }
    }

    /**
     * Returns the maximum number of colors the Toolkit supports in a custom cursor
     * palette.<p>
     * Note: if an image is used which has more colors in its palette than
     * the supported maximum, the Toolkit implementation will attempt to flatten the
     * palette to the maximum.  Since converting low-resolution images is difficult,
     * no guarantees are made as to the quality of a cursor image which has more
     * colors than the system supports.  It is therefore recommended that this method
     * be called and an appropriate image used so no image conversion is made.
     *
     * @return    the maximum number of colors, or zero if custom cursors are not
     * supported by this Toolkit implementation.
     * @throws HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since     1.2
     */
    public int getMaximumCursorColors() throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        // Override to implement custom cursor support.
        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().getMaximumCursorColors();
        } else {
            return 0;
        }
    }

    /**
     * Returns whether Toolkit supports this state for
     * {@code Frame}s.  This method tells whether the <em>UI
     * concept</em> of, say, maximization or iconification is
     * supported.  It will always return false for "compound" states
     * like {@code Frame.ICONIFIED|Frame.MAXIMIZED_VERT}.
     * In other words, the rule of thumb is that only queries with a
     * single frame state constant as an argument are meaningful.
     * <p>Note that supporting a given concept is a platform-
     * dependent feature. Due to native limitations the Toolkit
     * object may report a particular state as supported, however at
     * the same time the Toolkit object will be unable to apply the
     * state to a given frame.  This circumstance has two following
     * consequences:
     * <ul>
     * <li>Only the return value of {@code false} for the present
     * method actually indicates that the given state is not
     * supported. If the method returns {@code true} the given state
     * may still be unsupported and/or unavailable for a particular
     * frame.
     * <li>The developer should consider examining the value of the
     * {@link java.awt.event.WindowEvent#getNewState} method of the
     * {@code WindowEvent} received through the {@link
     * java.awt.event.WindowStateListener}, rather than assuming
     * that the state given to the {@code setExtendedState()} method
     * will be definitely applied. For more information see the
     * documentation for the {@link Frame#setExtendedState} method.
     * </ul>
     *
     * @param state one of named frame state constants.
     * @return {@code true} is this frame state is supported by
     *     this Toolkit implementation, {@code false} otherwise.
     * @throws HeadlessException
     *     if {@code GraphicsEnvironment.isHeadless()}
     *     returns {@code true}.
     * @see java.awt.Window#addWindowStateListener
     * @since   1.4
     */
    public boolean isFrameStateSupported(int state)
        throws HeadlessException
    {
        GraphicsEnvironment.checkHeadless();

        if (this != Toolkit.getDefaultToolkit()) {
            return Toolkit.getDefaultToolkit().
                isFrameStateSupported(state);
        } else {
            return (state == Frame.NORMAL); // others are not guaranteed
        }
    }

    /**
     * Support for I18N: any visible strings should be stored in
     * sun.awt.resources.awt.properties.  The ResourceBundle is stored
     * here, so that only one copy is maintained.
     */
    private static ResourceBundle resources;
    private static ResourceBundle platformResources;

    // called by platform toolkit
    private static void setPlatformResources(ResourceBundle bundle) {
        platformResources = bundle;
    }

    /**
     * Initialize JNI field and method ids
     */
    private static native void initIDs();

    /**
     * WARNING: This is a temporary workaround for a problem in the
     * way the AWT loads native libraries. A number of classes in the
     * AWT package have a native method, initIDs(), which initializes
     * the JNI field and method ids used in the native portion of
     * their implementation.
     *
     * Since the use and storage of these ids is done by the
     * implementation libraries, the implementation of these method is
     * provided by the particular AWT implementations (for example,
     * "Toolkit"s/Peer), such as Motif, Microsoft Windows, or Tiny. The
     * problem is that this means that the native libraries must be
     * loaded by the java.* classes, which do not necessarily know the
     * names of the libraries to load. A better way of doing this
     * would be to provide a separate library which defines java.awt.*
     * initIDs, and exports the relevant symbols out to the
     * implementation libraries.
     *
     * For now, we know it's done by the implementation, and we assume
     * that the name of the library is "awt".  -br.
     *
     * If you change loadLibraries(), please add the change to
     * java.awt.image.ColorModel.loadLibraries(). Unfortunately,
     * classes can be loaded in java.awt.image that depend on
     * libawt and there is no way to call Toolkit.loadLibraries()
     * directly.  -hung
     */
    private static boolean loaded = false;
    @SuppressWarnings("removal")
    static void loadLibraries() {
        if (!loaded) {
            java.security.AccessController.doPrivileged(
                new java.security.PrivilegedAction<Void>() {
                    public Void run() {
                        System.loadLibrary("awt");
                        return null;
                    }
                });
            loaded = true;
        }
    }

    static {
        initStatic();
    }

    @SuppressWarnings("removal")
    private static void initStatic() {
        AWTAccessor.setToolkitAccessor(
                new AWTAccessor.ToolkitAccessor() {
                    @Override
                    public void setPlatformResources(ResourceBundle bundle) {
                        Toolkit.setPlatformResources(bundle);
                    }
                });

        java.security.AccessController.doPrivileged(
                                 new java.security.PrivilegedAction<Void>() {
            public Void run() {
                try {
                    resources = ResourceBundle.getBundle("sun.awt.resources.awt");
                } catch (MissingResourceException e) {
                    // No resource file; defaults will be used.
                }
                return null;
            }
        });

        // ensure that the proper libraries are loaded
        loadLibraries();
        initAssistiveTechnologies();
        initIDs();
    }

    /**
     * Gets a property with the specified key and default.
     * This method returns defaultValue if the property is not found.
     *
     * @param  key the key
     * @param  defaultValue the default value
     * @return the value of the property or the default value
     *         if the property was not found
     */
    public static String getProperty(String key, String defaultValue) {
        // first try platform specific bundle
        if (platformResources != null) {
            try {
                return platformResources.getString(key);
            }
            catch (MissingResourceException e) {}
        }

        // then shared one
        if (resources != null) {
            try {
                return resources.getString(key);
            }
            catch (MissingResourceException e) {}
        }

        return defaultValue;
    }

    /**
     * Get the application's or applet's EventQueue instance.
     * Depending on the Toolkit implementation, different EventQueues
     * may be returned for different applets.  Applets should
     * therefore not assume that the EventQueue instance returned
     * by this method will be shared by other applets or the system.
     *
     * <p> If there is a security manager then its
     * {@link SecurityManager#checkPermission checkPermission} method
     * is called to check {@code AWTPermission("accessEventQueue")}.
     *
     * @return    the {@code EventQueue} object
     * @throws  SecurityException
     *          if a security manager is set and it denies access to
     *          the {@code EventQueue}
     * @see     java.awt.AWTPermission
    */
    public final EventQueue getSystemEventQueue() {
        @SuppressWarnings("removal")
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
            security.checkPermission(AWTPermissions.CHECK_AWT_EVENTQUEUE_PERMISSION);
        }
        return getSystemEventQueueImpl();
    }

    /**
     * Gets the application's or applet's {@code EventQueue}
     * instance, without checking access.  For security reasons,
     * this can only be called from a {@code Toolkit} subclass.
     * @return the {@code EventQueue} object
     */
    protected abstract EventQueue getSystemEventQueueImpl();

    /* Accessor method for use by AWT package routines. */
    static EventQueue getEventQueue() {
        return getDefaultToolkit().getSystemEventQueueImpl();
    }

    /**
     * Creates a concrete, platform dependent, subclass of the abstract
     * DragGestureRecognizer class requested, and associates it with the
     * DragSource, Component and DragGestureListener specified.
     *
     * subclasses should override this to provide their own implementation
     *
     * @param <T> the type of DragGestureRecognizer to create
     * @param abstractRecognizerClass The abstract class of the required recognizer
     * @param ds                      The DragSource
     * @param c                       The Component target for the DragGestureRecognizer
     * @param srcActions              The actions permitted for the gesture
     * @param dgl                     The DragGestureListener
     *
     * @return the new object or null.  Always returns null if
     * GraphicsEnvironment.isHeadless() returns true.
     * @see java.awt.GraphicsEnvironment#isHeadless
     */
    public <T extends DragGestureRecognizer> T
        createDragGestureRecognizer(Class<T> abstractRecognizerClass,
                                    DragSource ds, Component c, int srcActions,
                                    DragGestureListener dgl)
    {
        return null;
    }

    /**
     * Obtains a value for the specified desktop property.
     *
     * A desktop property is a uniquely named value for a resource that
     * is Toolkit global in nature. Usually it also is an abstract
     * representation for an underlying platform dependent desktop setting.
     * For more information on desktop properties supported by the AWT see
     * <a href="doc-files/DesktopProperties.html">AWT Desktop Properties</a>.
     *
     * @param  propertyName the property name
     * @return the value for the specified desktop property
     */
    public final synchronized Object getDesktopProperty(String propertyName) {
        // This is a workaround for headless toolkits.  It would be
        // better to override this method but it is declared final.
        // "this instanceof" syntax defeats polymorphism.
        // --mm, 03/03/00
        if (this instanceof HeadlessToolkit) {
            return ((HeadlessToolkit)this).getUnderlyingToolkit()
                .getDesktopProperty(propertyName);
        }

        if (desktopProperties.isEmpty()) {
            initializeDesktopProperties();
        }

        Object value;

        // This property should never be cached
        if (propertyName.equals("awt.dynamicLayoutSupported")) {
            return getDefaultToolkit().lazilyLoadDesktopProperty(propertyName);
        }

        value = desktopProperties.get(propertyName);

        if (value == null) {
            value = lazilyLoadDesktopProperty(propertyName);

            if (value != null) {
                setDesktopProperty(propertyName, value);
            }
        }

        /* for property "awt.font.desktophints" */
        if (value instanceof RenderingHints) {
            value = ((RenderingHints)value).clone();
        }

        return value;
    }

    /**
     * Sets the named desktop property to the specified value and fires a
     * property change event to notify any listeners that the value has changed.
     *
     * @param  name the property name
     * @param  newValue the new property value
     */
    protected final void setDesktopProperty(String name, Object newValue) {
        // This is a workaround for headless toolkits.  It would be
        // better to override this method but it is declared final.
        // "this instanceof" syntax defeats polymorphism.
        // --mm, 03/03/00
        if (this instanceof HeadlessToolkit) {
            ((HeadlessToolkit)this).getUnderlyingToolkit()
                .setDesktopProperty(name, newValue);
            return;
        }
        Object oldValue;

        synchronized (this) {
            oldValue = desktopProperties.get(name);
            desktopProperties.put(name, newValue);
        }

        // Don't fire change event if old and new values are null.
        // It helps to avoid recursive resending of WM_THEMECHANGED
        if (oldValue != null || newValue != null) {
            desktopPropsSupport.firePropertyChange(name, oldValue, newValue);
        }
    }

    /**
     * An opportunity to lazily evaluate desktop property values.
     * @return the desktop property or null
     * @param name the name
     */
    protected Object lazilyLoadDesktopProperty(String name) {
        return null;
    }

    /**
     * initializeDesktopProperties
     */
    protected void initializeDesktopProperties() {
    }

    /**
     * Adds the specified property change listener for the named desktop
     * property. When a {@link java.beans.PropertyChangeListenerProxy} object is added,
     * its property name is ignored, and the wrapped listener is added.
     * If {@code name} is {@code null} or {@code pcl} is {@code null},
     * no exception is thrown and no action is performed.
     *
     * @param   name The name of the property to listen for
     * @param   pcl The property change listener
     * @see PropertyChangeSupport#addPropertyChangeListener(String,
                PropertyChangeListener)
     * @since   1.2
     */
    public void addPropertyChangeListener(String name, PropertyChangeListener pcl) {
        desktopPropsSupport.addPropertyChangeListener(name, pcl);
    }

    /**
     * Removes the specified property change listener for the named
     * desktop property. When a {@link java.beans.PropertyChangeListenerProxy} object
     * is removed, its property name is ignored, and
     * the wrapped listener is removed.
     * If {@code name} is {@code null} or {@code pcl} is {@code null},
     * no exception is thrown and no action is performed.
     *
     * @param   name The name of the property to remove
     * @param   pcl The property change listener
     * @see PropertyChangeSupport#removePropertyChangeListener(String,
                PropertyChangeListener)
     * @since   1.2
     */
    public void removePropertyChangeListener(String name, PropertyChangeListener pcl) {
        desktopPropsSupport.removePropertyChangeListener(name, pcl);
    }

    /**
     * Returns an array of all the property change listeners
     * registered on this toolkit. The returned array
     * contains {@link java.beans.PropertyChangeListenerProxy} objects
     * that associate listeners with the names of desktop properties.
     *
     * @return all of this toolkit's {@link PropertyChangeListener}
     *         objects wrapped in {@code java.beans.PropertyChangeListenerProxy} objects
     *         or an empty array  if no listeners are added
     *
     * @see PropertyChangeSupport#getPropertyChangeListeners()
     * @since 1.4
     */
    public PropertyChangeListener[] getPropertyChangeListeners() {
        return desktopPropsSupport.getPropertyChangeListeners();
    }

    /**
     * Returns an array of all property change listeners
     * associated with the specified name of a desktop property.
     *
     * @param  propertyName the named property
     * @return all of the {@code PropertyChangeListener} objects
     *         associated with the specified name of a desktop property
     *         or an empty array if no such listeners are added
     *
     * @see PropertyChangeSupport#getPropertyChangeListeners(String)
     * @since 1.4
     */
    public PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
        return desktopPropsSupport.getPropertyChangeListeners(propertyName);
    }

    /**
     * The desktop properties.
     */
    protected final Map<String,Object> desktopProperties =
            new HashMap<String,Object>();
    /**
     * The desktop properties change support.
     */
    protected final PropertyChangeSupport desktopPropsSupport =
            Toolkit.createPropertyChangeSupport(this);

    /**
     * Returns whether the always-on-top mode is supported by this toolkit.
     * To detect whether the always-on-top mode is supported for a
     * particular Window, use {@link Window#isAlwaysOnTopSupported}.
     * @return {@code true}, if current toolkit supports the always-on-top mode,
     *     otherwise returns {@code false}
     * @see Window#isAlwaysOnTopSupported
     * @see Window#setAlwaysOnTop(boolean)
     * @since 1.6
     */
    public boolean isAlwaysOnTopSupported() {
        return true;
    }

    /**
     * Returns whether the given modality type is supported by this toolkit. If
     * a dialog with unsupported modality type is created, then
     * {@code Dialog.ModalityType.MODELESS} is used instead.
     *
     * @param modalityType modality type to be checked for support by this toolkit
     *
     * @return {@code true}, if current toolkit supports given modality
     *     type, {@code false} otherwise
     *
     * @see java.awt.Dialog.ModalityType
     * @see java.awt.Dialog#getModalityType
     * @see java.awt.Dialog#setModalityType
     *
     * @since 1.6
     */
    public abstract boolean isModalityTypeSupported(Dialog.ModalityType modalityType);

    /**
     * Returns whether the given modal exclusion type is supported by this
     * toolkit. If an unsupported modal exclusion type property is set on a window,
     * then {@code Dialog.ModalExclusionType.NO_EXCLUDE} is used instead.
     *
     * @param modalExclusionType modal exclusion type to be checked for support by this toolkit
     *
     * @return {@code true}, if current toolkit supports given modal exclusion
     *     type, {@code false} otherwise
     *
     * @see java.awt.Dialog.ModalExclusionType
     * @see java.awt.Window#getModalExclusionType
     * @see java.awt.Window#setModalExclusionType
     *
     * @since 1.6
     */
    public abstract boolean isModalExclusionTypeSupported(Dialog.ModalExclusionType modalExclusionType);

    // 8014718: logging has been removed from SunToolkit

    private static final int LONG_BITS = 64;
    private int[] calls = new int[LONG_BITS];
    private static volatile long enabledOnToolkitMask;
    private AWTEventListener eventListener = null;
    private WeakHashMap<AWTEventListener, SelectiveAWTEventListener> listener2SelectiveListener = new WeakHashMap<>();

    /*
     * Extracts a "pure" AWTEventListener from a AWTEventListenerProxy,
     * if the listener is proxied.
     */
    private static AWTEventListener deProxyAWTEventListener(AWTEventListener l)
    {
        AWTEventListener localL = l;

        if (localL == null) {
            return null;
        }
        // if user passed in a AWTEventListenerProxy object, extract
        // the listener
        if (l instanceof AWTEventListenerProxy) {
            localL = ((AWTEventListenerProxy)l).getListener();
        }
        return localL;
    }

    /**
     * Adds an AWTEventListener to receive all AWTEvents dispatched
     * system-wide that conform to the given {@code eventMask}.
     * <p>
     * First, if there is a security manager, its {@code checkPermission}
     * method is called with an
     * {@code AWTPermission("listenToAllAWTEvents")} permission.
     * This may result in a SecurityException.
     * <p>
     * {@code eventMask} is a bitmask of event types to receive.
     * It is constructed by bitwise OR-ing together the event masks
     * defined in {@code AWTEvent}.
     * <p>
     * Note:  event listener use is not recommended for normal
     * application use, but are intended solely to support special
     * purpose facilities including support for accessibility,
     * event record/playback, and diagnostic tracing.
     *
     * If listener is null, no exception is thrown and no action is performed.
     *
     * @param    listener   the event listener.
     * @param    eventMask  the bitmask of event types to receive
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow the operation.
     * @see      #removeAWTEventListener
     * @see      #getAWTEventListeners
     * @see      SecurityManager#checkPermission
     * @see      java.awt.AWTEvent
     * @see      java.awt.AWTPermission
     * @see      java.awt.event.AWTEventListener
     * @see      java.awt.event.AWTEventListenerProxy
     * @since    1.2
     */
    public void addAWTEventListener(AWTEventListener listener, long eventMask) {
        AWTEventListener localL = deProxyAWTEventListener(listener);

        if (localL == null) {
            return;
        }
        @SuppressWarnings("removal")
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
          security.checkPermission(AWTPermissions.ALL_AWT_EVENTS_PERMISSION);
        }
        synchronized (this) {
            SelectiveAWTEventListener selectiveListener =
                listener2SelectiveListener.get(localL);

            if (selectiveListener == null) {
                // Create a new selectiveListener.
                selectiveListener = new SelectiveAWTEventListener(localL,
                                                                 eventMask);
                listener2SelectiveListener.put(localL, selectiveListener);
                eventListener = ToolkitEventMulticaster.add(eventListener,
                                                            selectiveListener);
            }
            // OR the eventMask into the selectiveListener's event mask.
            selectiveListener.orEventMasks(eventMask);

            enabledOnToolkitMask |= eventMask;

            long mask = eventMask;
            for (int i=0; i<LONG_BITS; i++) {
                // If no bits are set, break out of loop.
                if (mask == 0) {
                    break;
                }
                if ((mask & 1L) != 0) {  // Always test bit 0.
                    calls[i]++;
                }
                mask >>>= 1;  // Right shift, fill with zeros on left.
            }
        }
    }

    /**
     * Removes an AWTEventListener from receiving dispatched AWTEvents.
     * <p>
     * First, if there is a security manager, its {@code checkPermission}
     * method is called with an
     * {@code AWTPermission("listenToAllAWTEvents")} permission.
     * This may result in a SecurityException.
     * <p>
     * Note:  event listener use is not recommended for normal
     * application use, but are intended solely to support special
     * purpose facilities including support for accessibility,
     * event record/playback, and diagnostic tracing.
     *
     * If listener is null, no exception is thrown and no action is performed.
     *
     * @param    listener   the event listener.
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow the operation.
     * @see      #addAWTEventListener
     * @see      #getAWTEventListeners
     * @see      SecurityManager#checkPermission
     * @see      java.awt.AWTEvent
     * @see      java.awt.AWTPermission
     * @see      java.awt.event.AWTEventListener
     * @see      java.awt.event.AWTEventListenerProxy
     * @since    1.2
     */
    public void removeAWTEventListener(AWTEventListener listener) {
        AWTEventListener localL = deProxyAWTEventListener(listener);

        if (listener == null) {
            return;
        }
        @SuppressWarnings("removal")
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
            security.checkPermission(AWTPermissions.ALL_AWT_EVENTS_PERMISSION);
        }

        synchronized (this) {
            SelectiveAWTEventListener selectiveListener =
                listener2SelectiveListener.get(localL);

            if (selectiveListener != null) {
                listener2SelectiveListener.remove(localL);
                int[] listenerCalls = selectiveListener.getCalls();
                for (int i=0; i<LONG_BITS; i++) {
                    calls[i] -= listenerCalls[i];
                    assert calls[i] >= 0: "Negative Listeners count";

                    if (calls[i] == 0) {
                        enabledOnToolkitMask &= ~(1L<<i);
                    }
                }
            }
            eventListener = ToolkitEventMulticaster.remove(eventListener,
            (selectiveListener == null) ? localL : selectiveListener);
        }
    }

    static boolean enabledOnToolkit(long eventMask) {
        return (enabledOnToolkitMask & eventMask) != 0;
        }

    synchronized int countAWTEventListeners(long eventMask) {
        int ci = 0;
        for (; eventMask != 0; eventMask >>>= 1, ci++) {
        }
        ci--;
        return calls[ci];
    }
    /**
     * Returns an array of all the {@code AWTEventListener}s
     * registered on this toolkit.
     * If there is a security manager, its {@code checkPermission}
     * method is called with an
     * {@code AWTPermission("listenToAllAWTEvents")} permission.
     * This may result in a SecurityException.
     * Listeners can be returned
     * within {@code AWTEventListenerProxy} objects, which also contain
     * the event mask for the given listener.
     * Note that listener objects
     * added multiple times appear only once in the returned array.
     *
     * @return all of the {@code AWTEventListener}s or an empty
     *         array if no listeners are currently registered
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow the operation.
     * @see      #addAWTEventListener
     * @see      #removeAWTEventListener
     * @see      SecurityManager#checkPermission
     * @see      java.awt.AWTEvent
     * @see      java.awt.AWTPermission
     * @see      java.awt.event.AWTEventListener
     * @see      java.awt.event.AWTEventListenerProxy
     * @since 1.4
     */
    public AWTEventListener[] getAWTEventListeners() {
        @SuppressWarnings("removal")
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
            security.checkPermission(AWTPermissions.ALL_AWT_EVENTS_PERMISSION);
        }
        synchronized (this) {
            EventListener[] la = ToolkitEventMulticaster.getListeners(eventListener,AWTEventListener.class);

            AWTEventListener[] ret = new AWTEventListener[la.length];
            for (int i = 0; i < la.length; i++) {
                SelectiveAWTEventListener sael = (SelectiveAWTEventListener)la[i];
                AWTEventListener tempL = sael.getListener();
                //assert tempL is not an AWTEventListenerProxy - we should
                // have weeded them all out
                // don't want to wrap a proxy inside a proxy
                ret[i] = new AWTEventListenerProxy(sael.getEventMask(), tempL);
            }
            return ret;
        }
    }

    /**
     * Returns an array of all the {@code AWTEventListener}s
     * registered on this toolkit which listen to all of the event
     * types specified in the {@code eventMask} argument.
     * If there is a security manager, its {@code checkPermission}
     * method is called with an
     * {@code AWTPermission("listenToAllAWTEvents")} permission.
     * This may result in a SecurityException.
     * Listeners can be returned
     * within {@code AWTEventListenerProxy} objects, which also contain
     * the event mask for the given listener.
     * Note that listener objects
     * added multiple times appear only once in the returned array.
     *
     * @param  eventMask the bitmask of event types to listen for
     * @return all of the {@code AWTEventListener}s registered
     *         on this toolkit for the specified
     *         event types, or an empty array if no such listeners
     *         are currently registered
     * @throws SecurityException
     *        if a security manager exists and its
     *        {@code checkPermission} method doesn't allow the operation.
     * @see      #addAWTEventListener
     * @see      #removeAWTEventListener
     * @see      SecurityManager#checkPermission
     * @see      java.awt.AWTEvent
     * @see      java.awt.AWTPermission
     * @see      java.awt.event.AWTEventListener
     * @see      java.awt.event.AWTEventListenerProxy
     * @since 1.4
     */
    public AWTEventListener[] getAWTEventListeners(long eventMask) {
        @SuppressWarnings("removal")
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
            security.checkPermission(AWTPermissions.ALL_AWT_EVENTS_PERMISSION);
        }
        synchronized (this) {
            EventListener[] la = ToolkitEventMulticaster.getListeners(eventListener,AWTEventListener.class);

            java.util.List<AWTEventListenerProxy> list = new ArrayList<>(la.length);

            for (int i = 0; i < la.length; i++) {
                SelectiveAWTEventListener sael = (SelectiveAWTEventListener)la[i];
                if ((sael.getEventMask() & eventMask) == eventMask) {
                    //AWTEventListener tempL = sael.getListener();
                    list.add(new AWTEventListenerProxy(sael.getEventMask(),
                                                       sael.getListener()));
                }
            }
            return list.toArray(new AWTEventListener[0]);
        }
    }

    /*
     * This method notifies any AWTEventListeners that an event
     * is about to be dispatched.
     *
     * @param theEvent the event which will be dispatched.
     */
    void notifyAWTEventListeners(AWTEvent theEvent) {
        // This is a workaround for headless toolkits.  It would be
        // better to override this method but it is declared package private.
        // "this instanceof" syntax defeats polymorphism.
        // --mm, 03/03/00
        if (this instanceof HeadlessToolkit) {
            ((HeadlessToolkit)this).getUnderlyingToolkit()
                .notifyAWTEventListeners(theEvent);
            return;
        }

        AWTEventListener eventListener = this.eventListener;
        if (eventListener != null) {
            eventListener.eventDispatched(theEvent);
        }
    }

    private static class ToolkitEventMulticaster extends AWTEventMulticaster
        implements AWTEventListener {
        // Implementation cloned from AWTEventMulticaster.

        ToolkitEventMulticaster(AWTEventListener a, AWTEventListener b) {
            super(a, b);
        }

        @SuppressWarnings("overloads")
        static AWTEventListener add(AWTEventListener a,
                                    AWTEventListener b) {
            if (a == null)  return b;
            if (b == null)  return a;
            return new ToolkitEventMulticaster(a, b);
        }

        @SuppressWarnings("overloads")
        static AWTEventListener remove(AWTEventListener l,
                                       AWTEventListener oldl) {
            return (AWTEventListener) removeInternal(l, oldl);
        }

        // #4178589: must overload remove(EventListener) to call our add()
        // instead of the static addInternal() so we allocate a
        // ToolkitEventMulticaster instead of an AWTEventMulticaster.
        // Note: this method is called by AWTEventListener.removeInternal(),
        // so its method signature must match AWTEventListener.remove().
        protected EventListener remove(EventListener oldl) {
            if (oldl == a)  return b;
            if (oldl == b)  return a;
            AWTEventListener a2 = (AWTEventListener)removeInternal(a, oldl);
            AWTEventListener b2 = (AWTEventListener)removeInternal(b, oldl);
            if (a2 == a && b2 == b) {
                return this;    // it's not here
            }
            return add(a2, b2);
        }

        public void eventDispatched(AWTEvent event) {
            ((AWTEventListener)a).eventDispatched(event);
            ((AWTEventListener)b).eventDispatched(event);
        }
    }

    private static class SelectiveAWTEventListener implements AWTEventListener {
        AWTEventListener listener;
        private long eventMask;
        // This array contains the number of times to call the eventlistener
        // for each event type.
        int[] calls = new int[Toolkit.LONG_BITS];

        public AWTEventListener getListener() {return listener;}
        public long getEventMask() {return eventMask;}
        public int[] getCalls() {return calls;}

        public void orEventMasks(long mask) {
            eventMask |= mask;
            // For each event bit set in mask, increment its call count.
            for (int i=0; i<Toolkit.LONG_BITS; i++) {
                // If no bits are set, break out of loop.
                if (mask == 0) {
                    break;
                }
                if ((mask & 1L) != 0) {  // Always test bit 0.
                    calls[i]++;
                }
                mask >>>= 1;  // Right shift, fill with zeros on left.
            }
        }

        SelectiveAWTEventListener(AWTEventListener l, long mask) {
            listener = l;
            eventMask = mask;
        }

        public void eventDispatched(AWTEvent event) {
            long eventBit = 0; // Used to save the bit of the event type.
            if (((eventBit = eventMask & AWTEvent.COMPONENT_EVENT_MASK) != 0 &&
                 event.id >= ComponentEvent.COMPONENT_FIRST &&
                 event.id <= ComponentEvent.COMPONENT_LAST)
             || ((eventBit = eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 &&
                 event.id >= ContainerEvent.CONTAINER_FIRST &&
                 event.id <= ContainerEvent.CONTAINER_LAST)
             || ((eventBit = eventMask & AWTEvent.FOCUS_EVENT_MASK) != 0 &&
                 event.id >= FocusEvent.FOCUS_FIRST &&
                 event.id <= FocusEvent.FOCUS_LAST)
             || ((eventBit = eventMask & AWTEvent.KEY_EVENT_MASK) != 0 &&
                 event.id >= KeyEvent.KEY_FIRST &&
                 event.id <= KeyEvent.KEY_LAST)
             || ((eventBit = eventMask & AWTEvent.MOUSE_WHEEL_EVENT_MASK) != 0 &&
                 event.id == MouseEvent.MOUSE_WHEEL)
             || ((eventBit = eventMask & AWTEvent.MOUSE_MOTION_EVENT_MASK) != 0 &&
                 (event.id == MouseEvent.MOUSE_MOVED ||
                  event.id == MouseEvent.MOUSE_DRAGGED))
             || ((eventBit = eventMask & AWTEvent.MOUSE_EVENT_MASK) != 0 &&
                 event.id != MouseEvent.MOUSE_MOVED &&
                 event.id != MouseEvent.MOUSE_DRAGGED &&
                 event.id != MouseEvent.MOUSE_WHEEL &&
                 event.id >= MouseEvent.MOUSE_FIRST &&
                 event.id <= MouseEvent.MOUSE_LAST)
             || ((eventBit = eventMask & AWTEvent.WINDOW_EVENT_MASK) != 0 &&
                 (event.id >= WindowEvent.WINDOW_FIRST &&
                 event.id <= WindowEvent.WINDOW_LAST))
             || ((eventBit = eventMask & AWTEvent.ACTION_EVENT_MASK) != 0 &&
                 event.id >= ActionEvent.ACTION_FIRST &&
                 event.id <= ActionEvent.ACTION_LAST)
             || ((eventBit = eventMask & AWTEvent.ADJUSTMENT_EVENT_MASK) != 0 &&
                 event.id >= AdjustmentEvent.ADJUSTMENT_FIRST &&
                 event.id <= AdjustmentEvent.ADJUSTMENT_LAST)
             || ((eventBit = eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 &&
                 event.id >= ItemEvent.ITEM_FIRST &&
                 event.id <= ItemEvent.ITEM_LAST)
             || ((eventBit = eventMask & AWTEvent.TEXT_EVENT_MASK) != 0 &&
                 event.id >= TextEvent.TEXT_FIRST &&
                 event.id <= TextEvent.TEXT_LAST)
             || ((eventBit = eventMask & AWTEvent.INPUT_METHOD_EVENT_MASK) != 0 &&
                 event.id >= InputMethodEvent.INPUT_METHOD_FIRST &&
                 event.id <= InputMethodEvent.INPUT_METHOD_LAST)
             || ((eventBit = eventMask & AWTEvent.PAINT_EVENT_MASK) != 0 &&
                 event.id >= PaintEvent.PAINT_FIRST &&
                 event.id <= PaintEvent.PAINT_LAST)
             || ((eventBit = eventMask & AWTEvent.INVOCATION_EVENT_MASK) != 0 &&
                 event.id >= InvocationEvent.INVOCATION_FIRST &&
                 event.id <= InvocationEvent.INVOCATION_LAST)
             || ((eventBit = eventMask & AWTEvent.HIERARCHY_EVENT_MASK) != 0 &&
                 event.id == HierarchyEvent.HIERARCHY_CHANGED)
             || ((eventBit = eventMask & AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK) != 0 &&
                 (event.id == HierarchyEvent.ANCESTOR_MOVED ||
                  event.id == HierarchyEvent.ANCESTOR_RESIZED))
             || ((eventBit = eventMask & AWTEvent.WINDOW_STATE_EVENT_MASK) != 0 &&
                 event.id == WindowEvent.WINDOW_STATE_CHANGED)
             || ((eventBit = eventMask & AWTEvent.WINDOW_FOCUS_EVENT_MASK) != 0 &&
                 (event.id == WindowEvent.WINDOW_GAINED_FOCUS ||
                  event.id == WindowEvent.WINDOW_LOST_FOCUS))
                || ((eventBit = eventMask & sun.awt.SunToolkit.GRAB_EVENT_MASK) != 0 &&
                    (event instanceof sun.awt.UngrabEvent))) {
                // Get the index of the call count for this event type.
                // Instead of using Math.log(...) we will calculate it with
                // bit shifts. That's what previous implementation looked like:
                //
                // int ci = (int) (Math.log(eventBit)/Math.log(2));
                int ci = 0;
                for (long eMask = eventBit; eMask != 0; eMask >>>= 1, ci++) {
                }
                ci--;
                // Call the listener as many times as it was added for this
                // event type.
                for (int i=0; i<calls[ci]; i++) {
                    listener.eventDispatched(event);
                }
            }
        }
    }

    /**
     * Returns a map of visual attributes for the abstract level description
     * of the given input method highlight, or null if no mapping is found.
     * The style field of the input method highlight is ignored. The map
     * returned is unmodifiable.
     * @param highlight input method highlight
     * @return style attribute map, or {@code null}
     * @throws HeadlessException if
     *     {@code GraphicsEnvironment.isHeadless} returns true
     * @see       java.awt.GraphicsEnvironment#isHeadless
     * @since 1.3
     */
    public abstract Map<java.awt.font.TextAttribute,?>
        mapInputMethodHighlight(InputMethodHighlight highlight)
        throws HeadlessException;

    private static PropertyChangeSupport createPropertyChangeSupport(Toolkit toolkit) {
        if (toolkit instanceof SunToolkit || toolkit instanceof HeadlessToolkit) {
            return new DesktopPropertyChangeSupport(toolkit);
        } else {
            return new PropertyChangeSupport(toolkit);
        }
    }

    /**
     * This is a utility class to support desktop properties.
     */
    @SuppressWarnings("serial")
    private static class DesktopPropertyChangeSupport extends PropertyChangeSupport {

        private static final StringBuilder PROP_CHANGE_SUPPORT_KEY =
                new StringBuilder("desktop property change support key");
        private final Object source;

        public DesktopPropertyChangeSupport(Object sourceBean) {
            super(sourceBean);
            source = sourceBean;
        }

        @Override
        public synchronized void addPropertyChangeListener(
                String propertyName,
                PropertyChangeListener listener)
        {
            PropertyChangeSupport pcs = (PropertyChangeSupport)
                    AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
            if (null == pcs) {
                pcs = new PropertyChangeSupport(source);
                AppContext.getAppContext().put(PROP_CHANGE_SUPPORT_KEY, pcs);
            }
            pcs.addPropertyChangeListener(propertyName, listener);
        }

        @Override
        public synchronized void removePropertyChangeListener(
                String propertyName,
                PropertyChangeListener listener)
        {
            PropertyChangeSupport pcs = (PropertyChangeSupport)
                    AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
            if (null != pcs) {
                pcs.removePropertyChangeListener(propertyName, listener);
            }
        }

        @Override
        public synchronized PropertyChangeListener[] getPropertyChangeListeners()
        {
            PropertyChangeSupport pcs = (PropertyChangeSupport)
                    AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
            if (null != pcs) {
                return pcs.getPropertyChangeListeners();
            } else {
                return new PropertyChangeListener[0];
            }
        }

        @Override
        public synchronized PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
        {
            PropertyChangeSupport pcs = (PropertyChangeSupport)
                    AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
            if (null != pcs) {
                return pcs.getPropertyChangeListeners(propertyName);
            } else {
                return new PropertyChangeListener[0];
            }
        }

        @Override
        public synchronized void addPropertyChangeListener(PropertyChangeListener listener) {
            PropertyChangeSupport pcs = (PropertyChangeSupport)
                    AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
            if (null == pcs) {
                pcs = new PropertyChangeSupport(source);
                AppContext.getAppContext().put(PROP_CHANGE_SUPPORT_KEY, pcs);
            }
            pcs.addPropertyChangeListener(listener);
        }

        @Override
        public synchronized void removePropertyChangeListener(PropertyChangeListener listener) {
            PropertyChangeSupport pcs = (PropertyChangeSupport)
                    AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
            if (null != pcs) {
                pcs.removePropertyChangeListener(listener);
            }
        }

        /*
         * we do expect that all other fireXXX() methods of java.beans.PropertyChangeSupport
         * use this method.  If this will be changed we will need to change this class.
         */
        @Override
        public void firePropertyChange(final PropertyChangeEvent evt) {
            Object oldValue = evt.getOldValue();
            Object newValue = evt.getNewValue();
            String propertyName = evt.getPropertyName();
            if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
                return;
            }
            Runnable updater = new Runnable() {
                public void run() {
                    PropertyChangeSupport pcs = (PropertyChangeSupport)
                            AppContext.getAppContext().get(PROP_CHANGE_SUPPORT_KEY);
                    if (null != pcs) {
                        pcs.firePropertyChange(evt);
                    }
                }
            };
            final AppContext currentAppContext = AppContext.getAppContext();
            for (AppContext appContext : AppContext.getAppContexts()) {
                if (null == appContext || appContext.isDisposed()) {
                    continue;
                }
                if (currentAppContext == appContext) {
                    updater.run();
                } else {
                    final PeerEvent e = new PeerEvent(source, updater, PeerEvent.ULTIMATE_PRIORITY_EVENT);
                    SunToolkit.postEvent(appContext, e);
                }
            }
        }
    }

    /**
    * Reports whether events from extra mouse buttons are allowed to be processed and posted into
    * {@code EventQueue}.
    * <br>
    * To change the returned value it is necessary to set the {@code sun.awt.enableExtraMouseButtons}
    * property before the {@code Toolkit} class initialization. This setting could be done on the application
    * startup by the following command:
    * <pre>
    * java -Dsun.awt.enableExtraMouseButtons=false Application
    * </pre>
    * Alternatively, the property could be set in the application by using the following code:
    * <pre>
    * System.setProperty("sun.awt.enableExtraMouseButtons", "true");
    * </pre>
    * before the {@code Toolkit} class initialization.
    * If not set by the time of the {@code Toolkit} class initialization, this property will be
    * initialized with {@code true}.
    * Changing this value after the {@code Toolkit} class initialization will have no effect.
    *
    * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true
    * @return {@code true} if events from extra mouse buttons are allowed to be processed and posted;
    *         {@code false} otherwise
    * @see System#getProperty(String propertyName)
    * @see System#setProperty(String propertyName, String value)
    * @see java.awt.EventQueue
    * @since 1.7
     */
    public boolean areExtraMouseButtonsEnabled() throws HeadlessException {
        GraphicsEnvironment.checkHeadless();

        return Toolkit.getDefaultToolkit().areExtraMouseButtonsEnabled();
    }
}
