samples/CompiledApplet/TransformApplet.java

/*
 * @(#)$Id$
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * 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.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 2001, Sun
 * Microsystems., http://www.sun.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * @author Morten Jorgensen
 * @author Jacek Ambroziak
 *
 */

import java.applet.Applet;

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Frame;
import java.awt.Label;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.io.PrintWriter;
import java.io.StringWriter;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerException;
import javax.xml.transform.ErrorListener;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;

/**
 * This applet demonstrates how XSL transformations can be made to run in
 * browsers without native XSLT support.
 *
 * Note that the XSLTC transformation engine is invoked through the JAXP
 * interface, using the XSLTC "use-classpath" attribute.  The
 * "use-classpath" attribute specifies to the XSLTC TransformerFactory
 * that a precompiled version of the stylesheet (translet) may be available,
 * and that that should be used in preference to recompiling the stylesheet.
 */
public final class TransformApplet extends Applet {

    /**
     * This class implements a dialog box used for XSL messages/comments
     */
    public class MessageFrame extends Frame {

        public Frame frame;

        public class ButtonHandler implements ActionListener {
            public void actionPerformed(ActionEvent e) {
                frame.setVisible(false);
            }
        }

        /**
         * This method handles xml:message and xsl:comment by displaying
         * the message/comment in a dialog box.
         */
        public MessageFrame(String title, String message) {
            super(title);
            frame = this; // Make visible to ButtonHandler
            setSize(320,200);

            // Create a panel for the message itself
            Panel center = new Panel();
            center.add(new Label(message));

            // Create a panel for the 'OK' button
            Panel bottom = new Panel();
            Button okButton = new Button("   OK   ");
            okButton.addActionListener(new ButtonHandler());
            bottom.add(okButton);

            // Add the two panels to the window/frame
            add(center, BorderLayout.CENTER);
            add(bottom,BorderLayout.SOUTH);

            // Show the fecking thing
            setVisible(true);
        }

    }

    /**
     * The applet uses this method to display messages and comments
     * generated by xsl:message and xsl:comment elements.
     */
    public class AppletErrorListener implements ErrorListener {
        public void displayMessage(TransformerException e) {
            MessageFrame z = new MessageFrame("XSL transformation alert",
                                              e.getMessageAndLocation());
        }

        public void error(TransformerException e) {
            displayMessage(e);
        }

        public void fatalError(TransformerException e) {
            displayMessage(e);
        }

        public void warning(TransformerException e) {
            displayMessage(e);
        }
    }

    /**
     * This method is the main body of the applet. The method is called
     * by some JavaScript code in an HTML document.
     */
    public String transform(Object arg1, Object arg2) {
        // Convert the two arguments to strings.
        final String stylesheetURL = (String)arg1;
        final String documentURL = (String)arg2;

        // Initialise the output stream
        final StringWriter sout = new StringWriter();
        final PrintWriter out = new PrintWriter(sout);

        try {
            // Check that the parameters are valid
            if (stylesheetURL == null || documentURL == null) {
                out.println("<h1>Transformation error</h1>");
                out.println("The parameters <b><tt>stylesheetURL</tt></b> "+
                            "and <b><tt>source</tt></b> must be specified");
            }
            else {
                TransformerFactory tf = null;
                tf = TransformerFactory.newInstance();

                try {
                    tf.setAttribute("use-classpath", Boolean.TRUE);
                } catch (IllegalArgumentException iae) {
                    System.err.println(
                           "Could not set XSLTC-specific TransformerFactory "
                         + "attributes.  Transformation failed.");
                }
                Transformer t =
                         tf.newTransformer(new StreamSource(stylesheetURL));
                t.setErrorListener(new AppletErrorListener());

                final long start = System.currentTimeMillis();

                t.transform(new StreamSource(documentURL),
                            new StreamResult(out));

                final long done = System.currentTimeMillis() - start;
                out.println("<!-- transformed by XSLTC in "+done+"msecs -->");
            }
            // Now close up the sink, and return the HTML output in the
            // StringWrite object as a string.
            out.close();
            System.err.println("Transformation complete!");
            System.err.println(sout.toString());
            return sout.toString();
        }
        catch (RuntimeException e) {
            out.println("<h1>RTE</h1>");
            out.close();
            return sout.toString();
        }
        catch (Exception e) {
            out.println("<h1>exception</h1>");
            out.println(e.toString());
            out.close();
            return sout.toString();
        }
    }

    public void start() {
        String result = transform(getParameter("stylesheet-name"),
                                  getParameter("input-document"));
    }
}