/*
* @(#)$Id: TransformHandler.java,v 1.5 2003/01/30 15:59:24 zongaro Exp $
*
* 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
*
*/
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.StringTokenizer;
import org.apache.xalan.xsltc.dom.DOMImpl;
import org.apache.xalan.xsltc.dom.DocumentCache;
import org.apache.xalan.xsltc.runtime.AbstractTranslet;
import org.apache.xalan.xsltc.runtime.output.TransletOutputHandlerFactory;
import org.xml.sax.SAXException;
import sunlabs.brazil.server.Handler;
import sunlabs.brazil.server.Request;
import sunlabs.brazil.server.Server;
/**
* This Brazil handler demonstrates how XSL transformations can be made
* available as a web service without using a full web server. This class
* implements the Handler interface from the Brazil project, see:
* http://www.sun.com/research/brazil/
*
* Note that the XSLTC transformation engine is invoked through its native
* interface and not the javax.xml.transform (JAXP) interface. This because
* XSLTC still does not offer precompiled transformations through JAXP.
*/
public class TransformHandler implements Handler {
// A cache for internal DOM structures
private static DocumentCache cache = null;
// These two are used while parsing the parameters in the URL
private final String PARAM_TRANSLET = "translet=";
private final String PARAM_DOCUMENT = "document=";
private final String PARAM_STATS = "stats=";
// All output goes here:
private PrintWriter _out = null;
/**
* Dump an error message to output
*/
public void errorMessage(String message, Exception e) {
if (_out == null) return;
_out.println("<h1>XSL transformation error</h1>"+message);
_out.println("<br>Exception:</br>"+e.toString());
}
public void errorMessage(String message) {
if (_out == null) return;
_out.println("<h1>XSL transformation error</h1>"+message);
}
/**
* This method is run when the Brazil proxy is loaded
*/
public boolean init(Server server, String prefix) {
return true;
}
/**
* This method is run for every HTTP request sent to the proxy
*/
public boolean respond(Request request) throws IOException {
// Initialise the output buffer
final StringWriter sout = new StringWriter();
_out = new PrintWriter(sout);
// These two hold the parameters from the URL 'translet' and 'document'
String transletName = null;
String document = null;
String stats = null;
// Get the parameters from the URL
final StringTokenizer params = new StringTokenizer(request.query,"&");
while (params.hasMoreElements()) {
final String param = params.nextToken();
if (param.startsWith(PARAM_TRANSLET)) {
transletName = param.substring(PARAM_TRANSLET.length());
}
else if (param.startsWith(PARAM_DOCUMENT)) {
document = param.substring(PARAM_DOCUMENT.length());
}
else if (param.startsWith(PARAM_STATS)) {
stats = param.substring(PARAM_STATS.length());
}
}
try {
// Initialize the document cache with 32 DOM slots
if (cache == null) cache = new DocumentCache(32);
// Output statistics if user looked up "server:port/?stats=xxx"
if (stats != null) {
cache.getStatistics(_out); // get cache statistics (in HTML)
}
// Make sure that both parameters were specified
else if ((transletName == null) || (document == null)) {
errorMessage("Parameters <b><tt>translet</tt></b> and/or "+
"<b><tt>document</tt></b> not specified.");
}
else {
// Get a reference to the translet class
Class transletClass = Class.forName(transletName);
// Instanciate the translet object (inherits AbstractTranslet)
AbstractTranslet translet =
(AbstractTranslet)transletClass.newInstance();
translet.setDOMCache(cache);
// Get the DOM from the DOM cache
DOMImpl dom = cache.retrieveDocument(document, 0, translet);
if (dom == null) {
errorMessage("Could not locate: \"<b>"+document+"\"</b>");
}
else {
// Create output handler
TransletOutputHandlerFactory tohFactory =
TransletOutputHandlerFactory.newInstance();
tohFactory.setOutputType(TransletOutputHandlerFactory.STREAM);
tohFactory.setEncoding(translet._encoding);
tohFactory.setOutputMethod(translet._method);
tohFactory.setWriter(_out);
// Do the actual transformation
final long start = System.currentTimeMillis();
translet.transform(dom, tohFactory.getTransletOutputHandler());
final long done = System.currentTimeMillis() - start;
_out.println("<!-- transformed by XSLTC in "+done+"ms -->");
}
}
}
catch (SAXException e) {
errorMessage("Error parsing document \""+document+"\"");
}
catch (ClassNotFoundException e) {
errorMessage("Could not locate the translet class: \""+
transletName+"\"<br>Exception:</br>",e);
}
catch (Exception e) {
errorMessage("Internal error.",e);
}
// Pass the transformation output as the HTTP response
request.sendResponse(sout.toString());
return true;
}
}