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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* $Id: TransformHandler.java 470245 2006-11-02 06:34:33Z minchau $
*/
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.StringTokenizer;
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;
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 the JAXP
* interface, using the XSLTC "use-classpath" attribute. The
* "use-from-classpath" attribute specifies to the XSLTC TransformerFactory
* that a precompiled version of the stylesheet (translet) may be available,
* and that should be used in preference to recompiling the stylesheet.
* @author Morten Jorgensen
*/
public class TransformHandler implements Handler {
private TransformerFactory m_tf = 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 m_out = null;
/**
* Dump an error message to output
*/
public void errorMessage(String message, Exception e) {
if (m_out == null) {
return;
}
m_out.println("<h1>XSL transformation error</h1>"+message);
m_out.println("<br>Exception:</br>"+e.toString());
}
public void errorMessage(String message) {
if (m_out == null) return;
m_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();
m_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 {
// Make sure that both parameters were specified
if ((transletName == null) || (document == null)) {
errorMessage("Parameters <b><tt>translet</tt></b> and/or "+
"<b><tt>document</tt></b> not specified.");
}
else {
if (m_tf == null) {
m_tf = TransformerFactory.newInstance();
try {
m_tf.setAttribute("use-classpath", Boolean.TRUE);
} catch (IllegalArgumentException iae) {
System.err.println(
"Could not set XSLTC-specific TransformerFactory "
+ "attributes. Transformation failed.");
}
}
Transformer t =
m_tf.newTransformer(new StreamSource(transletName));
// Do the actual transformation
final long start = System.currentTimeMillis();
t.transform(new StreamSource(document),
new StreamResult(m_out));
final long done = System.currentTimeMillis() - start;
m_out.println("<!-- transformed by XSLTC in "+done+"ms -->");
}
}
catch (Exception e) {
errorMessage("Internal error.",e);
}
// Pass the transformation output as the HTTP response
request.sendResponse(sout.toString());
return true;
}
}
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