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 * 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,

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 *

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package java.awt;

import java.awt.desktop.AboutEvent;

import java.awt.desktop.AboutHandler;

import java.awt.desktop.OpenFilesHandler;

import java.awt.desktop.OpenURIEvent;

import java.awt.desktop.OpenURIHandler;

import java.awt.desktop.PreferencesEvent;

import java.awt.desktop.PreferencesHandler;

import java.awt.desktop.PrintFilesHandler;

import java.awt.desktop.QuitHandler;

import java.awt.desktop.QuitStrategy;

import java.awt.desktop.SystemEventListener;

import java.awt.peer.DesktopPeer;

import java.io.File;

import java.io.FilePermission;

import java.io.IOException;

import java.net.URI;

import java.net.URISyntaxException;

import java.util.Objects;

import javax.swing.JMenuBar;

import sun.awt.SunToolkit;

import sun.security.util.SecurityConstants;

/**

 * The {@code Desktop} class allows interact with various desktop capabilities.

 *

 * <p> Supported operations include:

 * <ul>

 *   <li>launching the user-default browser to show a specified

 *       URI;</li>

 *   <li>launching the user-default mail client with an optional

 *       {@code mailto} URI;</li>

 *   <li>launching a registered application to open, edit or print a

 *       specified file.</li>

 * </ul>

 *

 * <p> This class provides methods corresponding to these

 * operations. The methods look for the associated application

 * registered on the current platform, and launch it to handle a URI

 * or file. If there is no associated application or the associated

 * application fails to be launched, an exception is thrown.

 *

 * Please see {@link Desktop.Action} for the full list of supported operations

 * and capabilities.

 *

 * <p> An application is registered to a URI or file type.

 * The mechanism of registering, accessing, and

 * launching the associated application is platform-dependent.

 *

 * <p> Each operation is an action type represented by the {@link

 * Desktop.Action} class.

 *

 * <p> Note: when some action is invoked and the associated

 * application is executed, it will be executed on the same system as

 * the one on which the Java application was launched.

 *

 * <p> Note: the methods in the {@code Desktop} class may require

 * platform-dependent permissions in addition to those described in the

 * specification.

 *

 * @see Action

 *

 * @since 1.6

 * @author Armin Chen

 * @author George Zhang

 */

public class Desktop {

    /**

     * Represents an action type.  Each platform supports a different

     * set of actions.  You may use the {@link Desktop#isSupported}

     * method to determine if the given action is supported by the

     * current platform.

     * @see java.awt.Desktop#isSupported(java.awt.Desktop.Action)

     * @since 1.6

     */

    public static enum Action {

        /**

         * Represents an "open" action.

         * @see Desktop#open(java.io.File)

         */

        OPEN,

        /**

         * Represents an "edit" action.

         * @see Desktop#edit(java.io.File)

         */

        EDIT,

        /**

         * Represents a "print" action.

         * @see Desktop#print(java.io.File)

         */

        PRINT,

        /**

         * Represents a "mail" action.

         * @see Desktop#mail()

         * @see Desktop#mail(java.net.URI)

         */

        MAIL,

        /**

         * Represents a "browse" action.

         * @see Desktop#browse(java.net.URI)

         */

        BROWSE,

        /**

         * Represents an AppForegroundListener

         * @see java.awt.desktop.AppForegroundListener

         * @since 9

         */

        APP_EVENT_FOREGROUND,

        /**

         * Represents an AppHiddenListener

         * @see java.awt.desktop.AppHiddenListener

         * @since 9

         */

        APP_EVENT_HIDDEN,

        /**

         * Represents an AppReopenedListener

         * @see java.awt.desktop.AppReopenedListener

         * @since 9

         */

        APP_EVENT_REOPENED,

        /**

         * Represents a ScreenSleepListener

         * @see java.awt.desktop.ScreenSleepListener

         * @since 9

         */

        APP_EVENT_SCREEN_SLEEP,

        /**

         * Represents a SystemSleepListener

         * @see java.awt.desktop.SystemSleepListener

         * @since 9

         */

        APP_EVENT_SYSTEM_SLEEP,

        /**

         * Represents a UserSessionListener

         * @see java.awt.desktop.UserSessionListener

         * @since 9

         */

        APP_EVENT_USER_SESSION,

        /**

         * Represents an AboutHandler

         * @see #setAboutHandler(java.awt.desktop.AboutHandler)

         * @since 9

         */

        APP_ABOUT,

        /**

         * Represents a PreferencesHandler

         * @see #setPreferencesHandler(java.awt.desktop.PreferencesHandler)

         * @since 9

         */

        APP_PREFERENCES,

        /**

         * Represents an OpenFilesHandler

         * @see #setOpenFileHandler(java.awt.desktop.OpenFilesHandler)

         * @since 9

         */

        APP_OPEN_FILE,

        /**

         * Represents a PrintFilesHandler

         * @see #setPrintFileHandler(java.awt.desktop.PrintFilesHandler)

         * @since 9

         */

        APP_PRINT_FILE,

        /**

         * Represents an OpenURIHandler

         * @see #setOpenURIHandler(java.awt.desktop.OpenURIHandler)

         * @since 9

         */

        APP_OPEN_URI,

        /**

         * Represents a QuitHandler

         * @see #setQuitHandler(java.awt.desktop.QuitHandler)

         * @since 9

         */

        APP_QUIT_HANDLER,

        /**

         * Represents a QuitStrategy

         * @see #setQuitStrategy(java.awt.desktop.QuitStrategy)

         * @since 9

         */

        APP_QUIT_STRATEGY,

        /**

         * Represents a SuddenTermination

         * @see #enableSuddenTermination()

         * @since 9

         */

        APP_SUDDEN_TERMINATION,

        /**

         * Represents a requestForeground

         * @see #requestForeground(boolean)

         * @since 9

         */

        APP_REQUEST_FOREGROUND,

        /**

         * Represents a HelpViewer

         * @see #openHelpViewer()

         * @since 9

         */

        APP_HELP_VIEWER,

        /**

         * Represents a menu bar

         * @see #setDefaultMenuBar(javax.swing.JMenuBar)

         * @since 9

         */

        APP_MENU_BAR,

        /**

         * Represents a browse file directory

         * @see #browseFileDirectory(java.io.File)

         * @since 9

         */

        BROWSE_FILE_DIR,

        /**

         * Represents a move to trash

         * @see #moveToTrash(java.io.File)

         * @since 9

         */

        MOVE_TO_TRASH

    };

    private DesktopPeer peer;

    /**

     * Suppresses default constructor for noninstantiability.

     */

    private Desktop() {

        Toolkit defaultToolkit = Toolkit.getDefaultToolkit();

        // same cast as in isDesktopSupported()

        if (defaultToolkit instanceof SunToolkit) {

            peer = ((SunToolkit) defaultToolkit).createDesktopPeer(this);

        }

    }

    private void checkEventsProcessingPermission() {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(new RuntimePermission(

                    "canProcessApplicationEvents"));

        }

    }

    /**

     * Returns the {@code Desktop} instance of the current

     * desktop context. On some platforms the Desktop API may not be

     * supported; use the {@link #isDesktopSupported} method to

     * determine if the current desktop is supported.

     * @return the Desktop instance

     * @throws HeadlessException if {@link

     * GraphicsEnvironment#isHeadless()} returns {@code true}

     * @throws UnsupportedOperationException if this class is not

     * supported on the current platform

     * @see #isDesktopSupported()

     * @see java.awt.GraphicsEnvironment#isHeadless

     */

    public static synchronized Desktop getDesktop(){

        if (GraphicsEnvironment.isHeadless()) throw new HeadlessException();

        if (!Desktop.isDesktopSupported()) {

            throw new UnsupportedOperationException("Desktop API is not " +

                                                    "supported on the current platform");

        }

        sun.awt.AppContext context = sun.awt.AppContext.getAppContext();

        Desktop desktop = (Desktop)context.get(Desktop.class);

        if (desktop == null) {

            desktop = new Desktop();

            context.put(Desktop.class, desktop);

        }

        return desktop;

    }

    /**

     * Tests whether this class is supported on the current platform.

     * If it's supported, use {@link #getDesktop()} to retrieve an

     * instance.

     *

     * @return {@code true} if this class is supported on the

     *         current platform; {@code false} otherwise

     * @see #getDesktop()

     */

    public static boolean isDesktopSupported(){

        Toolkit defaultToolkit = Toolkit.getDefaultToolkit();

        if (defaultToolkit instanceof SunToolkit) {

            return ((SunToolkit)defaultToolkit).isDesktopSupported();

        }

        return false;

    }

    /**

     * Tests whether an action is supported on the current platform.

     *

     * <p>Even when the platform supports an action, a file or URI may

     * not have a registered application for the action.  For example,

     * most of the platforms support the {@link Desktop.Action#OPEN}

     * action.  But for a specific file, there may not be an

     * application registered to open it.  In this case, {@link

     * #isSupported(Action)} may return {@code true}, but the corresponding

     * action method will throw an {@link IOException}.

     *

     * @param action the specified {@link Action}

     * @return {@code true} if the specified action is supported on

     *         the current platform; {@code false} otherwise

     * @see Desktop.Action

     */

    public boolean isSupported(Action action) {

        return peer.isSupported(action);

    }

    /**

     * Checks if the file is a valid file and readable.

     *

     * @throws SecurityException If a security manager exists and its

     *         {@link SecurityManager#checkRead(java.lang.String)} method

     *         denies read access to the file

     * @throws NullPointerException if file is null

     * @throws IllegalArgumentException if file doesn't exist

     */

        if (!file.exists()) {

            throw new IllegalArgumentException("The file: "

                    + file.getPath() + " doesn't exist.");

        }

    }

    /**

     * Checks if the action type is supported.

     *

     * @param actionType the action type in question

     * @throws UnsupportedOperationException if the specified action type is not

     *         supported on the current platform

     */

    private void checkActionSupport(Action actionType){

        if (!isSupported(actionType)) {

            throw new UnsupportedOperationException("The " + actionType.name()

                    + " action is not supported on the current platform!");

        }

    }

    /**

     *  Calls to the security manager's {@code checkPermission} method with

     *  an {@code AWTPermission("showWindowWithoutWarningBanner")}

     *  permission.

     */

    private void checkAWTPermission(){

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(new AWTPermission(

                    "showWindowWithoutWarningBanner"));

        }

    }

    /**

     * Launches the associated application to open the file.

     *

     * <p> If the specified file is a directory, the file manager of

     * the current platform is launched to open it.

     *

     * @param file the file to be opened with the associated application

     * @throws NullPointerException if {@code file} is {@code null}

     * @throws IllegalArgumentException if the specified file doesn't

     * exist

     * @throws UnsupportedOperationException if the current platform

     * does not support the {@link Desktop.Action#OPEN} action

     * @throws IOException if the specified file has no associated

     * application or the associated application fails to be launched

     * @throws SecurityException if a security manager exists and its

     * {@link java.lang.SecurityManager#checkRead(java.lang.String)}

     * method denies read access to the file, or it denies the

     * {@code AWTPermission("showWindowWithoutWarningBanner")}

     * permission, or the calling thread is not allowed to create a

     * subprocess

     * @see java.awt.AWTPermission

     */

    public void open(File file) throws IOException {

        checkAWTPermission();

        checkExec();

        checkActionSupport(Action.OPEN);

        checkFileValidation(file);

        peer.open(file);

    }

    /**

     * Launches the associated editor application and opens a file for

     * editing.

     *

     * @param file the file to be opened for editing

     * @throws NullPointerException if the specified file is {@code null}

     * @throws IllegalArgumentException if the specified file doesn't

     * exist

     * @throws UnsupportedOperationException if the current platform

     * does not support the {@link Desktop.Action#EDIT} action

     * @throws IOException if the specified file has no associated

     * editor, or the associated application fails to be launched

     * @throws SecurityException if a security manager exists and its

     * {@link java.lang.SecurityManager#checkRead(java.lang.String)}

     * method denies read access to the file, or {@link

     * java.lang.SecurityManager#checkWrite(java.lang.String)} method

     * denies write access to the file, or it denies the

     * {@code AWTPermission("showWindowWithoutWarningBanner")}

     * permission, or the calling thread is not allowed to create a

     * subprocess

     * @see java.awt.AWTPermission

     */

    public void edit(File file) throws IOException {

        checkAWTPermission();

        checkExec();

        checkActionSupport(Action.EDIT);

        file.canWrite();

        checkFileValidation(file);

        peer.edit(file);

    }

    /**

     * Prints a file with the native desktop printing facility, using

     * the associated application's print command.

     *

     * @param file the file to be printed

     * @throws NullPointerException if the specified file is {@code

     * null}

     * @throws IllegalArgumentException if the specified file doesn't

     * exist

     * @throws UnsupportedOperationException if the current platform

     *         does not support the {@link Desktop.Action#PRINT} action

     * @throws IOException if the specified file has no associated

     * application that can be used to print it

     * @throws SecurityException if a security manager exists and its

     * {@link java.lang.SecurityManager#checkRead(java.lang.String)}

     * method denies read access to the file, or its {@link

     * java.lang.SecurityManager#checkPrintJobAccess()} method denies

     * the permission to print the file, or the calling thread is not

     * allowed to create a subprocess

     */

    public void print(File file) throws IOException {

        checkExec();

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPrintJobAccess();

        }

        checkActionSupport(Action.PRINT);

        checkFileValidation(file);

        peer.print(file);

    }

    /**

     * Launches the default browser to display a {@code URI}.

     * If the default browser is not able to handle the specified

     * {@code URI}, the application registered for handling

     * {@code URIs} of the specified type is invoked. The application

     * is determined from the protocol and path of the {@code URI}, as

     * defined by the {@code URI} class.

     *

     * @param uri the URI to be displayed in the user default browser