Redir.java Source code

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Here is the source code for Redir.java

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/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */

//applet.html

/*
<html>
<head>
   <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
   <title>We've moved!</title>
</head>
<body bgcolor="White">
<h1>We've moved!</h1>
<p>Please update your bookmarks. Our new address is:</P>
<applet code=Redir.class width=300 heighT=100 alt="http://www.java2s.com">
   <param name="URL" value="http://www.java2s.com">
   <b>http://www.java2s.com</b>
</applet>
<hr/>
<p>If you have a Java-enabled browser,
we'll try to take you there in a few seconds.</p>
</body>
</html>
    
    
*/

import java.applet.Applet;
import java.awt.Graphics;
import java.net.URL;

/**
 * A simple redirection applet.
 * 
 * @author Ian Darwin
 */
public class Redir extends Applet implements Runnable {
    protected String urlString;

    protected URL theNewURL;

    protected final static int NSECONDS = 5;

    protected Thread t;

    public void init() {
        try {
            // Get the address from a PARAM...
            urlString = getParameter("URL");
            if (urlString == null) {
                urlString = "MISSING URL";
                throw new IllegalArgumentException("Redir requires a URL parameter in the HTML");
            }

            // Make up the URL object
            theNewURL = new URL(urlString);

            // debug...
            // showStatus("URL = " + theNewURL);

        } catch (Exception err) {
            System.err.println("Error!\n" + err);
            showStatus("Error, look in Java Console for details!");
        }
    }

    public void start() {
        if (theNewURL == null)
            return;

        t = new Thread(this);
        t.start();
    }

    /** Print a little message to the user. */
    public void paint(Graphics g) {
        if (urlString != null)
            g.drawString(urlString, 20, 50);
        else
            g.drawString("Initializing...", 20, 50);
    }

    /**
     * If users moves off the page, set Thread t to null so we don't
     * showDocument from within the middle of the new page!
     */
    public void stop() {
        t = null;
    }

    /**
     * run, called by the Thread, does the work of sleeping for a fixed number
     * of seconds then, if the user hasn't moved off the page, actually passing
     * control to the new page.
     */
    public void run() {
        for (int i = NSECONDS; i >= 0; i--) {
            try {
                Thread.sleep(1000);
                if (t == null)
                    return;
            } catch (InterruptedException e) {
                // so what?
            }
            if (t == null)
                return;
            showStatus(Integer.toString(i));

            if (t == null)
                return;

            showStatus("Ignition!");
            // "And then a miracle occurs..."
            getAppletContext().showDocument(theNewURL);
        }
    }
}