BrowserControl.java

/*
 * From Steven Spencer's Java World article
 * 		http://www.javaworld.com/javatips/jw-javatip66_p.html
 */
package hermes.browser;

import java.io.IOException;

/**
 * A simple, static class to display a URL in the system browser.
 *
 * Under Unix, the system browser is hard-coded to be 'netscape'.
 * Netscape must be in your PATH for this to work.  This has been
 * tested with the following platforms: AIX, HP-UX and Solaris.
 *
 * Under Windows, this will bring up the default browser under windows,
 * usually either Netscape or Microsoft IE.  The default browser is
 * determined by the OS.  This has been tested under Windows 95/98/NT.
 *
 * Examples:
 * BrowserControl.displayURL("http://www.javaworld.com")
 * BrowserControl.displayURL("file://c:\\docs\\index.html")
 * BrowserContorl.displayURL("file:///user/joe/index.html");
 * 
 * @author peterlee@hermesjms.com last changed by: $Author: leepops $
 * @version $Id: BrowserControl.java,v 1.1 2004/09/27 21:25:53 leepops Exp $
 */
public class BrowserControl
{
	/**
	 * Display a file in the system browser.  If you want to display a
	 * file, you must include the absolute path name.
	 * @param url the file's url (the url must start with either "http://" or
	 * "file://").
	 */
	public static void displayURL(String url)
	{
		boolean windows = isWindowsPlatform();
		String cmd = null;
		
		try
		{
			if (windows)
			{
				// cmd = 'rundll32 url.dll,FileProtocolHandler http://...'
				cmd = WIN_PATH + " " + WIN_FLAG + " " + url;
				Process p = Runtime.getRuntime().exec(cmd);
			}
			else
			{
				// Under Unix, Netscape has to be running for the "-remote"
				// command to work.  So, we try sending the command and
				// check for an exit value.  If the exit command is 0,
				// it worked, otherwise we need to start the browser.
				// cmd = 'netscape -remote openURL(http://www.javaworld.com)'
				cmd = UNIX_PATH + " " + UNIX_FLAG + "(" + url + ")";
				Process p = Runtime.getRuntime().exec(cmd);
				try
				{
					// wait for exit code -- if it's 0, command worked,
					// otherwise we need to start the browser up.
					int exitCode = p.waitFor();
					if (exitCode != 0)
					{
						// Command failed, start up the browser
						// cmd = 'netscape http://www.javaworld.com'
						cmd = UNIX_PATH + " "  + url;
						p = Runtime.getRuntime().exec(cmd);
					}
				}
				catch(InterruptedException x)
				{
					System.err.println("Error bringing up browser, cmd='" +
									   cmd + "'");
					System.err.println("Caught: " + x);
				}
			}
		}
		catch(IOException x)
		{
			// couldn't exec browser
			System.err.println("Could not invoke browser, command=" + cmd);
			System.err.println("Caught: " + x);
		}
	}
	/**
	 * Try to determine whether this application is running under Windows
	 * or some other platform by examing the "os.name" property.
	 *
	 * @return true if this application is running under a Windows OS
	 */
	public static boolean isWindowsPlatform()
	{
		String os = System.getProperty("os.name");
		if ( os != null && os.startsWith(WIN_ID))
			return true;
		else
			return false;

	}
	
	// Used to identify the windows platform.
	private static final String WIN_ID = "Windows";
	// The default system browser under windows.
	private static final String WIN_PATH = "rundll32";
	// The flag to display a url.
	private static final String WIN_FLAG = "url.dll,FileProtocolHandler";
	// The default browser under unix.
	private static final String UNIX_PATH = "netscape";
	// The flag to display a url.
	private static final String UNIX_FLAG = "-remote openURL";
}