* 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. *
* 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. *
* 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. *
* 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. *
* Credits:
*
Steven Spencer, JavaWorld magazine
* (
* Java Tip 66)
*
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 (
* ejalbert@cs.stanford.edu)
* @version 1.4b1 (Released June 20, 2001)
*
* @author Jacob Dreyer
* Added methods to the API and adjusted the linux version slightly.
*/
public class Browser {
/**
* 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.
*
* Note that if this is false
, openURL()
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 true
if all intialization succeeded
* false
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[] { Browser.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;
}
// Avoid a FilenameFilter because that can't be stopped mid-list
String[] systemFolderFiles = systemFolder.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())) {
// Actually the Finder, but that's OK
browser = file.toString();
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;
}
/**
* Open the specified file in the client web browser.
*
* @param file File to open
* @throws IOException If there is brwoser problem.
*
*/
public static void openUrl (File file)
throws IOException
{
openUrl ("file://" + file.getPath());
}
/**
* Open the specified URL in the client web browser.
*
* @param url URL to open.
* @throws IOException If there is brwoser problem.
*/
public static void openUrl (URL url)
throws IOException
{
openUrl (url.toString());
}
/**
* Open the specified URL in the client web browser.
*
* @param url URL to open.
* @throws IOException If there is brwoser problem.
*/
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