/*

 * Copyright (c) 2008, 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 com.sun.servicetag;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.InvocationTargetException;

import java.io.IOException;

import java.net.URI;

/**

 * BrowserSupport class.

 *

 * The implementation of the com.sun.servicetag API needs to be

 * compiled with JDK 5 as well since the consumer of this API

 * may require to support JDK 5 (e.g. NetBeans).

 *

 * The Desktop.browse() method can be backported in this class

 * if needed.  The current implementation only supports JDK 6.

 */

class BrowserSupport {

    private static boolean isBrowseSupported = false;

    private static Method browseMethod = null;

    private static Object desktop = null;

    private static volatile Boolean result = false;

    private static void initX() {

        if  (desktop != null) {

            return;

        }

        boolean supported = false;

        Method browseM = null;

        Object desktopObj = null;

        try {

            // Determine if java.awt.Desktop is supported

            Class<?> desktopCls = Class.forName("java.awt.Desktop", true, null);

            Method getDesktopM = desktopCls.getMethod("getDesktop");

            browseM = desktopCls.getMethod("browse", URI.class);

            Class<?> actionCls = Class.forName("java.awt.Desktop$Action", true, null);

            final Method isDesktopSupportedMethod = desktopCls.getMethod("isDesktopSupported");

            Method isSupportedMethod = desktopCls.getMethod("isSupported", actionCls);

            Field browseField = actionCls.getField("BROWSE");

            // isDesktopSupported calls getDefaultToolkit which can block

            // infinitely, see 6636099 for details, to workaround we call

            // in a  thread and time it out, noting that the issue is specific

            // to X11, it does not hurt for Windows.

            Thread xthread = new Thread() {

                public void run() {

                    try {

                        // support only if Desktop.isDesktopSupported() and

                        // Desktop.isSupported(Desktop.Action.BROWSE) return true.

                        result = (Boolean) isDesktopSupportedMethod.invoke(null);

                    } catch (IllegalAccessException e) {

                        // should never reach here

                    } catch (InvocationTargetException e) {

                        // browser not supported

                        if (Util.isVerbose()) {

                            e.printStackTrace();

                        }

                    }

                }

            };

            // set it to daemon, so that the vm will exit.

            xthread.setDaemon(true);

            xthread.start();

            try {

                xthread.join(5 * 1000);

            } catch (InterruptedException ie) {

                // ignore the exception

            }

            if (result.booleanValue()) {

                desktopObj = getDesktopM.invoke(null);

                result = (Boolean) isSupportedMethod.invoke(desktopObj, browseField.get(null));

                supported = result.booleanValue();

            }

        } catch (IllegalAccessException e) {

            // should never reach here

            // browser not supported

            if (Util.isVerbose()) {

                e.printStackTrace();

            }

        }

        isBrowseSupported = supported;

        browseMethod = browseM;

        desktop = desktopObj;

    }

    static boolean isSupported() {

        initX();

        return isBrowseSupported;

    }

    /**

     * 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.

     * <p>

     * This method calls the Desktop.getDesktop().browse() method.

     * <p>

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

     *

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

     * @throws UnsupportedOperationException if the current platform

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

     * @throws IOException if the user default browser is not found,

     * or it fails to be launched, or the default handler application

     * failed to be launched

     * @throws IllegalArgumentException if the necessary permissions

     * are not available and the URI can not be converted to a {@code URL}

     */

    static void browse(URI uri) throws IOException {

        if (uri == null) {

            throw new NullPointerException("null uri");

        }

        if (!isSupported()) {

            throw new UnsupportedOperationException("Browse operation is not supported");

        }

        // Call Desktop.browse() method

        try {

            if (Util.isVerbose()) {

                System.out.println("desktop: " + desktop + ":browsing..." + uri);

            }

            browseMethod.invoke(desktop, uri);

        } catch (IllegalAccessException e) {

            // should never reach here

        } catch (InvocationTargetException e) {

            Throwable x = e.getCause();

            if (x != null) {

                if (x instanceof UnsupportedOperationException) {

                    throw (UnsupportedOperationException) x;

                } else if (x instanceof IllegalArgumentException) {

                    throw (IllegalArgumentException) x;

                } else if (x instanceof IOException) {

                    throw (IOException) x;

                } else if (x instanceof SecurityException) {

                    throw (SecurityException) x;

                } else {

                    // ignore

                }

            }

        }

    }

}