Browser Launcher
//package modrcon;
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;
/**
* 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 1.4b2 (Dec 26, 2007)
* @since 1.4b1 (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 = "firefox";
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);
}
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