* 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)
*/
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.
*
* 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[] { 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