BrowserLauncher.java 29.8 KB
Newer Older
1 2 3 4 5
/**
 * $RCSfile$
 * $Revision: 128 $
 * $Date: 2004-10-25 20:42:00 -0300 (Mon, 25 Oct 2004) $
 *
6
 * Copyright (C) 2004-2008 Jive Software. All rights reserved.
7
 *
8 9 10 11 12 13 14 15 16 17 18
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
19 20
 */

21
package org.jivesoftware.openfire.launcher;
22 23 24 25 26 27 28 29

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

30 31 32
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716
/**
 * BrowserLauncher is a class that provides one static method, openURL, which opens the default
 * web browser for the current user of the system to the given URL.  It may support other
 * protocols depending on the system -- mailto, ftp, etc. -- but that has not been rigorously
 * tested and is not guaranteed to work.
 * <p/>
 * Yes, this is platform-specific code, and yes, it may rely on classes on certain platforms
 * that are not part of the standard JDK.  What we're trying to do, though, is to take something
 * that's frequently desirable but inherently platform-specific -- opening a default browser --
 * and allow programmers (you, for example) to do so without worrying about dropping into native
 * code or doing anything else similarly evil.
 * <p/>
 * Anyway, this code is completely in Java and will run on all JDK 1.1-compliant systems without
 * modification or a need for additional libraries.  All classes that are required on certain
 * platforms to allow this to run are dynamically loaded at runtime via reflection and, if not
 * found, will not cause this to do anything other than returning an error when opening the
 * browser.
 * <p/>
 * There are certain system requirements for this class, as it's running through Runtime.exec(),
 * which is Java's way of making a native system call.  Currently, this requires that a Macintosh
 * have a Finder which supports the GURL event, which is true for Mac OS 8.0 and 8.1 systems that
 * have the Internet Scripting AppleScript dictionary installed in the Scripting Additions folder
 * in the Extensions folder (which is installed by default as far as I know under Mac OS 8.0 and
 * 8.1), and for all Mac OS 8.5 and later systems.  On Windows, it only runs under Win32 systems
 * (Windows 95, 98, and NT 4.0, as well as later versions of all).  On other systems, this drops
 * back from the inherently platform-sensitive concept of a default browser and simply attempts
 * to launch Netscape via a shell command.
 * <p/>
 * This code is Copyright 1999-2001 by Eric Albert (ejalbert@cs.stanford.edu) and may be
 * redistributed or modified in any form without restrictions as long as the portion of this
 * comment from this paragraph through the end of the comment is not removed.  The author
 * requests that he be notified of any application, applet, or other binary that makes use of
 * this code, but that's more out of curiosity than anything and is not required.  This software
 * includes no warranty.  The author is not repsonsible for any loss of data or functionality
 * or any adverse or unexpected effects of using this software.
 * <p/>
 * Credits:
 * <br>Steven Spencer, JavaWorld magazine (<a href="http://www.javaworld.com/javaworld/javatips/jw-javatip66.html">Java Tip 66</a>)
 * <br>Thanks also to Ron B. Yeh, Eric Shapiro, Ben Engber, Paul Teitlebaum, Andrea Cantatore,
 * Larry Barowski, Trevor Bedzek, Frank Miedrich, and Ron Rabakukk
 *
 * @author Eric Albert (<a href="mailto:ejalbert@cs.stanford.edu">ejalbert@cs.stanford.edu</a>)
 * @version 1.4b1 (Released June 20, 2001)
 */
public class BrowserLauncher {

    /**
     * The Java virtual machine that we are running on.  Actually, in most cases we only care
     * about the operating system, but some operating systems require us to switch on the VM.
     */
    private static int jvm;

    /**
     * The browser for the system
     */
    private static Object browser;

    /**
     * Caches whether any classes, methods, and fields that are not part of the JDK and need to
     * be dynamically loaded at runtime loaded successfully.
     * <p/>
     * Note that if this is <code>false</code>, <code>openURL()</code> will always return an
     * IOException.
     */
    private static boolean loadedWithoutErrors;

    /**
     * The com.apple.mrj.MRJFileUtils class
     */
    private static Class mrjFileUtilsClass;

    /**
     * The com.apple.mrj.MRJOSType class
     */
    private static Class mrjOSTypeClass;

    /**
     * The com.apple.MacOS.AEDesc class
     */
    private static Class aeDescClass;

    /**
     * The <init>(int) method of com.apple.MacOS.AETarget
     */
    private static Constructor aeTargetConstructor;

    /**
     * The <init>(int, int, int) method of com.apple.MacOS.AppleEvent
     */
    private static Constructor appleEventConstructor;

    /**
     * The <init>(String) method of com.apple.MacOS.AEDesc
     */
    private static Constructor aeDescConstructor;

    /**
     * The findFolder method of com.apple.mrj.MRJFileUtils
     */
    private static Method findFolder;

    /**
     * The getFileCreator method of com.apple.mrj.MRJFileUtils
     */
    private static Method getFileCreator;

    /**
     * The getFileType method of com.apple.mrj.MRJFileUtils
     */
    private static Method getFileType;

    /**
     * The openURL method of com.apple.mrj.MRJFileUtils
     */
    private static Method openURL;

    /**
     * The makeOSType method of com.apple.MacOS.OSUtils
     */
    private static Method makeOSType;

    /**
     * The putParameter method of com.apple.MacOS.AppleEvent
     */
    private static Method putParameter;

    /**
     * The sendNoReply method of com.apple.MacOS.AppleEvent
     */
    private static Method sendNoReply;

    /**
     * Actually an MRJOSType pointing to the System Folder on a Macintosh
     */
    private static Object kSystemFolderType;

    /**
     * The keyDirectObject AppleEvent parameter type
     */
    private static Integer keyDirectObject;

    /**
     * The kAutoGenerateReturnID AppleEvent code
     */
    private static Integer kAutoGenerateReturnID;

    /**
     * The kAnyTransactionID AppleEvent code
     */
    private static Integer kAnyTransactionID;

    /**
     * The linkage object required for JDirect 3 on Mac OS X.
     */
    private static Object linkage;

    /**
     * The framework to reference on Mac OS X
     */
    private static final String JDirect_MacOSX = "/System/Library/Frameworks/Carbon.framework/Frameworks/HIToolbox.framework/HIToolbox";

    /**
     * JVM constant for MRJ 2.0
     */
    private static final int MRJ_2_0 = 0;

    /**
     * JVM constant for MRJ 2.1 or later
     */
    private static final int MRJ_2_1 = 1;

    /**
     * JVM constant for Java on Mac OS X 10.0 (MRJ 3.0)
     */
    private static final int MRJ_3_0 = 3;

    /**
     * JVM constant for MRJ 3.1
     */
    private static final int MRJ_3_1 = 4;

    /**
     * JVM constant for any Windows NT JVM
     */
    private static final int WINDOWS_NT = 5;

    /**
     * JVM constant for any Windows 9x JVM
     */
    private static final int WINDOWS_9x = 6;

    /**
     * JVM constant for any other platform
     */
    private static final int OTHER = -1;

    /**
     * The file type of the Finder on a Macintosh.  Hardcoding "Finder" would keep non-U.S. English
     * systems from working properly.
     */
    private static final String FINDER_TYPE = "FNDR";

    /**
     * The creator code of the Finder on a Macintosh, which is needed to send AppleEvents to the
     * application.
     */
    private static final String FINDER_CREATOR = "MACS";

    /**
     * The name for the AppleEvent type corresponding to a GetURL event.
     */
    private static final String GURL_EVENT = "GURL";

    /**
     * The first parameter that needs to be passed into Runtime.exec() to open the default web
     * browser on Windows.
     */
    private static final String FIRST_WINDOWS_PARAMETER = "/c";

    /**
     * The second parameter for Runtime.exec() on Windows.
     */
    private static final String SECOND_WINDOWS_PARAMETER = "start";

    /**
     * The third parameter for Runtime.exec() on Windows.  This is a "title"
     * parameter that the command line expects.  Setting this parameter allows
     * URLs containing spaces to work.
     */
    private static final String THIRD_WINDOWS_PARAMETER = "\"\"";

    /**
     * The shell parameters for Netscape that opens a given URL in an already-open copy of Netscape
     * on many command-line systems.
     */
    private static final String NETSCAPE_REMOTE_PARAMETER = "-remote";
    private static final String NETSCAPE_OPEN_PARAMETER_START = "'openURL(";
    private static final String NETSCAPE_OPEN_PARAMETER_END = ")'";

    /**
     * The message from any exception thrown throughout the initialization process.
     */
    private static String errorMessage;

    /**
     * An initialization block that determines the operating system and loads the necessary
     * runtime data.
     */
    static {
        loadedWithoutErrors = true;
        String osName = System.getProperty("os.name");
        if (osName.startsWith("Mac OS")) {
            String mrjVersion = System.getProperty("mrj.version");
            String majorMRJVersion = mrjVersion.substring(0, 3);
            try {
                double version = Double.valueOf(majorMRJVersion).doubleValue();
                if (version == 2) {
                    jvm = MRJ_2_0;
                }
                else if (version >= 2.1 && version < 3) {
                    // Assume that all 2.x versions of MRJ work the same.  MRJ 2.1 actually
                    // works via Runtime.exec() and 2.2 supports that but has an openURL() method
                    // as well that we currently ignore.
                    jvm = MRJ_2_1;
                }
                else if (version == 3.0) {
                    jvm = MRJ_3_0;
                }
                else if (version >= 3.1) {
                    // Assume that all 3.1 and later versions of MRJ work the same.
                    jvm = MRJ_3_1;
                }
                else {
                    loadedWithoutErrors = false;
                    errorMessage = "Unsupported MRJ version: " + version;
                }
            }
            catch (NumberFormatException nfe) {
                loadedWithoutErrors = false;
                errorMessage = "Invalid MRJ version: " + mrjVersion;
            }
        }
        else if (osName.startsWith("Windows")) {
            if (osName.indexOf("9") != -1) {
                jvm = WINDOWS_9x;
            }
            else {
                jvm = WINDOWS_NT;
            }
        }
        else {
            jvm = OTHER;
        }

        if (loadedWithoutErrors) {	// if we haven't hit any errors yet
            loadedWithoutErrors = loadClasses();
        }
    }

    /**
     * This class should be never be instantiated; this just ensures so.
     */
    private BrowserLauncher() {
    }

    /**
     * Called by a static initializer to load any classes, fields, and methods required at runtime
     * to locate the user's web browser.
     *
     * @return <code>true</code> if all intialization succeeded
     *         <code>false</code> if any portion of the initialization failed
     */
    private static boolean loadClasses() {
        switch (jvm) {
            case MRJ_2_0:
                try {
                    Class aeTargetClass = Class.forName("com.apple.MacOS.AETarget");
                    Class osUtilsClass = Class.forName("com.apple.MacOS.OSUtils");
                    Class appleEventClass = Class.forName("com.apple.MacOS.AppleEvent");
                    Class aeClass = Class.forName("com.apple.MacOS.ae");
                    aeDescClass = Class.forName("com.apple.MacOS.AEDesc");

                    aeTargetConstructor = aeTargetClass.getDeclaredConstructor(new Class[]{int.class});
                    appleEventConstructor = appleEventClass.getDeclaredConstructor(new Class[]{int.class, int.class, aeTargetClass, int.class, int.class});
                    aeDescConstructor = aeDescClass.getDeclaredConstructor(new Class[]{String.class});

                    makeOSType = osUtilsClass.getDeclaredMethod("makeOSType", new Class[]{String.class});
                    putParameter = appleEventClass.getDeclaredMethod("putParameter", new Class[]{int.class, aeDescClass});
                    sendNoReply = appleEventClass.getDeclaredMethod("sendNoReply", new Class[]{});

                    Field keyDirectObjectField = aeClass.getDeclaredField("keyDirectObject");
                    keyDirectObject = (Integer)keyDirectObjectField.get(null);
                    Field autoGenerateReturnIDField = appleEventClass.getDeclaredField("kAutoGenerateReturnID");
                    kAutoGenerateReturnID = (Integer)autoGenerateReturnIDField.get(null);
                    Field anyTransactionIDField = appleEventClass.getDeclaredField("kAnyTransactionID");
                    kAnyTransactionID = (Integer)anyTransactionIDField.get(null);
                }
                catch (ClassNotFoundException cnfe) {
                    errorMessage = cnfe.getMessage();
                    return false;
                }
                catch (NoSuchMethodException nsme) {
                    errorMessage = nsme.getMessage();
                    return false;
                }
                catch (NoSuchFieldException nsfe) {
                    errorMessage = nsfe.getMessage();
                    return false;
                }
                catch (IllegalAccessException iae) {
                    errorMessage = iae.getMessage();
                    return false;
                }
                break;
            case MRJ_2_1:
                try {
                    mrjFileUtilsClass = Class.forName("com.apple.mrj.MRJFileUtils");
                    mrjOSTypeClass = Class.forName("com.apple.mrj.MRJOSType");
                    Field systemFolderField = mrjFileUtilsClass.getDeclaredField("kSystemFolderType");
                    kSystemFolderType = systemFolderField.get(null);
                    findFolder = mrjFileUtilsClass.getDeclaredMethod("findFolder", new Class[]{mrjOSTypeClass});
                    getFileCreator = mrjFileUtilsClass.getDeclaredMethod("getFileCreator", new Class[]{File.class});
                    getFileType = mrjFileUtilsClass.getDeclaredMethod("getFileType", new Class[]{File.class});
                }
                catch (ClassNotFoundException cnfe) {
                    errorMessage = cnfe.getMessage();
                    return false;
                }
                catch (NoSuchFieldException nsfe) {
                    errorMessage = nsfe.getMessage();
                    return false;
                }
                catch (NoSuchMethodException nsme) {
                    errorMessage = nsme.getMessage();
                    return false;
                }
                catch (SecurityException se) {
                    errorMessage = se.getMessage();
                    return false;
                }
                catch (IllegalAccessException iae) {
                    errorMessage = iae.getMessage();
                    return false;
                }
                break;
            case MRJ_3_0:
                try {
                    Class linker = Class.forName("com.apple.mrj.jdirect.Linker");
                    Constructor constructor = linker.getConstructor(new Class[]{Class.class});
                    linkage = constructor.newInstance(new Object[]{BrowserLauncher.class});
                }
                catch (ClassNotFoundException cnfe) {
                    errorMessage = cnfe.getMessage();
                    return false;
                }
                catch (NoSuchMethodException nsme) {
                    errorMessage = nsme.getMessage();
                    return false;
                }
                catch (InvocationTargetException ite) {
                    errorMessage = ite.getMessage();
                    return false;
                }
                catch (InstantiationException ie) {
                    errorMessage = ie.getMessage();
                    return false;
                }
                catch (IllegalAccessException iae) {
                    errorMessage = iae.getMessage();
                    return false;
                }
                break;
            case MRJ_3_1:
                try {
                    mrjFileUtilsClass = Class.forName("com.apple.mrj.MRJFileUtils");
                    openURL = mrjFileUtilsClass.getDeclaredMethod("openURL", new Class[]{String.class});
                }
                catch (ClassNotFoundException cnfe) {
                    errorMessage = cnfe.getMessage();
                    return false;
                }
                catch (NoSuchMethodException nsme) {
                    errorMessage = nsme.getMessage();
                    return false;
                }
                break;
            default:
                break;
        }
        return true;
    }

    /**
     * Attempts to locate the default web browser on the local system.  Caches results so it
     * only locates the browser once for each use of this class per JVM instance.
     *
     * @return The browser for the system.  Note that this may not be what you would consider
     *         to be a standard web browser; instead, it's the application that gets called to
     *         open the default web browser.  In some cases, this will be a non-String object
     *         that provides the means of calling the default browser.
     */
    private static Object locateBrowser() {
        if (browser != null) {
            return browser;
        }
        switch (jvm) {
            case MRJ_2_0:
                try {
                    Integer finderCreatorCode = (Integer)makeOSType.invoke(null, new Object[]{FINDER_CREATOR});
                    Object aeTarget = aeTargetConstructor.newInstance(new Object[]{finderCreatorCode});
                    Integer gurlType = (Integer)makeOSType.invoke(null, new Object[]{GURL_EVENT});
                    Object appleEvent = appleEventConstructor.newInstance(new Object[]{gurlType, gurlType, aeTarget, kAutoGenerateReturnID, kAnyTransactionID});
                    // Don't set browser = appleEvent because then the next time we call
                    // locateBrowser(), we'll get the same AppleEvent, to which we'll already have
                    // added the relevant parameter. Instead, regenerate the AppleEvent every time.
                    // There's probably a way to do this better; if any has any ideas, please let
                    // me know.
                    return appleEvent;
                }
                catch (IllegalAccessException iae) {
                    browser = null;
                    errorMessage = iae.getMessage();
                    return browser;
                }
                catch (InstantiationException ie) {
                    browser = null;
                    errorMessage = ie.getMessage();
                    return browser;
                }
                catch (InvocationTargetException ite) {
                    browser = null;
                    errorMessage = ite.getMessage();
                    return browser;
                }
            case MRJ_2_1:
                File systemFolder;
                try {
                    systemFolder = (File)findFolder.invoke(null, new Object[]{kSystemFolderType});
                }
                catch (IllegalArgumentException iare) {
                    browser = null;
                    errorMessage = iare.getMessage();
                    return browser;
                }
                catch (IllegalAccessException iae) {
                    browser = null;
                    errorMessage = iae.getMessage();
                    return browser;
                }
                catch (InvocationTargetException ite) {
                    browser = null;
                    errorMessage = ite.getTargetException().getClass() + ": " + ite.getTargetException().getMessage();
                    return browser;
                }
                String[] systemFolderFiles = systemFolder.list();
                // Avoid a FilenameFilter because that can't be stopped mid-list
                for (int i = 0; i < systemFolderFiles.length; i++) {
                    try {
                        File file = new File(systemFolder, systemFolderFiles[i]);
                        if (!file.isFile()) {
                            continue;
                        }
                        // We're looking for a file with a creator code of 'MACS' and
                        // a type of 'FNDR'.  Only requiring the type results in non-Finder
                        // applications being picked up on certain Mac OS 9 systems,
                        // especially German ones, and sending a GURL event to those
                        // applications results in a logout under Multiple Users.
                        Object fileType = getFileType.invoke(null, new Object[]{file});
                        if (FINDER_TYPE.equals(fileType.toString())) {
                            Object fileCreator = getFileCreator.invoke(null, new Object[]{file});
                            if (FINDER_CREATOR.equals(fileCreator.toString())) {
                                browser = file.toString();	// Actually the Finder, but that's OK
                                return browser;
                            }
                        }
                    }
                    catch (IllegalArgumentException iare) {
                        browser = browser;
                        errorMessage = iare.getMessage();
                        return null;
                    }
                    catch (IllegalAccessException iae) {
                        browser = null;
                        errorMessage = iae.getMessage();
                        return browser;
                    }
                    catch (InvocationTargetException ite) {
                        browser = null;
                        errorMessage = ite.getTargetException().getClass() + ": " + ite.getTargetException().getMessage();
                        return browser;
                    }
                }
                browser = null;
                break;
            case MRJ_3_0:
            case MRJ_3_1:
                browser = "";	// Return something non-null
                break;
            case WINDOWS_NT:
                browser = "cmd.exe";
                break;
            case WINDOWS_9x:
                browser = "command.com";
                break;
            case OTHER:
            default:
                browser = "netscape";
                break;
        }
        return browser;
    }

    /**
     * Attempts to open the default web browser to the given URL.
     *
     * @param url The URL to open
     * @throws IOException If the web browser could not be located or does not run
     */
    public static void openURL(String url) throws IOException {
        if (!loadedWithoutErrors) {
            throw new IOException("Exception in finding browser: " + errorMessage);
        }
        Object browser = locateBrowser();
        if (browser == null) {
            throw new IOException("Unable to locate browser: " + errorMessage);
        }

        switch (jvm) {
            case MRJ_2_0:
                Object aeDesc = null;
                try {
                    aeDesc = aeDescConstructor.newInstance(new Object[]{url});
                    putParameter.invoke(browser, new Object[]{keyDirectObject, aeDesc});
                    sendNoReply.invoke(browser, new Object[]{});
                }
                catch (InvocationTargetException ite) {
                    throw new IOException("InvocationTargetException while creating AEDesc: " + ite.getMessage());
                }
                catch (IllegalAccessException iae) {
                    throw new IOException("IllegalAccessException while building AppleEvent: " + iae.getMessage());
                }
                catch (InstantiationException ie) {
                    throw new IOException("InstantiationException while creating AEDesc: " + ie.getMessage());
                }
                finally {
                    aeDesc = null;	// Encourage it to get disposed if it was created
                    browser = null;	// Ditto
                }
                break;
            case MRJ_2_1:
                Runtime.getRuntime().exec(new String[]{(String)browser, url});
                break;
            case MRJ_3_0:
                int[] instance = new int[1];
                int result = ICStart(instance, 0);
                if (result == 0) {
                    int[] selectionStart = new int[]{0};
                    byte[] urlBytes = url.getBytes();
                    int[] selectionEnd = new int[]{urlBytes.length};
                    result = ICLaunchURL(instance[0], new byte[]{0}, urlBytes,
                            urlBytes.length, selectionStart,
                            selectionEnd);
                    if (result == 0) {
                        // Ignore the return value; the URL was launched successfully
                        // regardless of what happens here.
                        ICStop(instance);
                    }
                    else {
                        throw new IOException("Unable to launch URL: " + result);
                    }
                }
                else {
                    throw new IOException("Unable to create an Internet Config instance: " + result);
                }
                break;
            case MRJ_3_1:
                try {
                    openURL.invoke(null, new Object[]{url});
                }
                catch (InvocationTargetException ite) {
                    throw new IOException("InvocationTargetException while calling openURL: " + ite.getMessage());
                }
                catch (IllegalAccessException iae) {
                    throw new IOException("IllegalAccessException while calling openURL: " + iae.getMessage());
                }
                break;
            case WINDOWS_NT:
            case WINDOWS_9x:
                // Add quotes around the URL to allow ampersands and other special
                // characters to work.
                Process process = Runtime.getRuntime().exec(new String[]{(String)browser,
                                                                         FIRST_WINDOWS_PARAMETER,
                                                                         SECOND_WINDOWS_PARAMETER,
                                                                         THIRD_WINDOWS_PARAMETER,
                                                                         '"' + url + '"'});
                // This avoids a memory leak on some versions of Java on Windows.
                // That's hinted at in <http://developer.java.sun.com/developer/qow/archive/68/>.
                try {
                    process.waitFor();
                    process.exitValue();
                }
                catch (InterruptedException ie) {
                    throw new IOException("InterruptedException while launching browser: " + ie.getMessage());
                }
                break;
            case OTHER:
                // Assume that we're on Unix and that Netscape is installed

                // First, attempt to open the URL in a currently running session of Netscape
                process = Runtime.getRuntime().exec(new String[]{(String)browser,
                                                                 NETSCAPE_REMOTE_PARAMETER,
                                                                 NETSCAPE_OPEN_PARAMETER_START +
                        url +
                        NETSCAPE_OPEN_PARAMETER_END});
                try {
                    int exitCode = process.waitFor();
                    if (exitCode != 0) {	// if Netscape was not open
                        Runtime.getRuntime().exec(new String[]{(String)browser, url});
                    }
                }
                catch (InterruptedException ie) {
                    throw new IOException("InterruptedException while launching browser: " + ie.getMessage());
                }
                break;
            default:
                // This should never occur, but if it does, we'll try the simplest thing possible
                Runtime.getRuntime().exec(new String[]{(String)browser, url});
                break;
        }
    }

    /**
     * Methods required for Mac OS X.  The presence of native methods does not cause
     * any problems on other platforms.
     */
    private native static int ICStart(int[] instance, int signature);

    private native static int ICStop(int[] instance);

    private native static int ICLaunchURL(int instance, byte[] hint, byte[] data, int len,
                                          int[] selectionStart, int[] selectionEnd);
}