package org.apache.turbine.services.xslt;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 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 "Apache" and "Apache Software Foundation" and
* "Apache Turbine" 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",
* "Apache Turbine", 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. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.Hashtable;
import org.apache.turbine.services.BaseInitable;
import org.apache.turbine.services.TurbineBaseService;
import org.apache.turbine.services.TurbineServices;
import org.apache.turbine.services.resources.TurbineResources;
import org.apache.turbine.services.servlet.TurbineServlet;
import org.apache.turbine.util.Log;
import org.apache.xalan.xslt.StylesheetRoot;
import org.apache.xalan.xslt.XSLTInputSource;
import org.apache.xalan.xslt.XSLTProcessor;
import org.apache.xalan.xslt.XSLTProcessorFactory;
import org.apache.xalan.xslt.XSLTResultTarget;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
/**
* Implementation of the Turbine XSLT Service. It transforms xml with a given
* xsl file. XSL stylesheets are compiled and cached (if the property in
* TurbineResources.properties is set) to improve speeds.
*
* @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
*/
public class TurbineXSLTService
extends TurbineBaseService
implements XSLTService
{
/**
* Property to control the caching of StyleSheetRoots.
*/
protected boolean caching = false;
/**
* Path to style sheets used for tranforming well-formed
* XML documents. The path is relative to the webapp context.
*/
protected String path;
/**
* Cache of compiled StyleSheetRoots.
*/
protected Hashtable cache = new Hashtable();
/**
* Initialize the TurbineXSLT Service. Load the path to search for
* xsl files and initiates the cache.
*/
public void init()
{
if (getInit())
{
return;
}
path = TurbineResources.getString (
TurbineServices.SERVICE_PREFIX +
XSLTService.SERVICE_NAME + ".path");
path = TurbineServlet.getRealPath (path);
if (!path.endsWith("/") && !path.endsWith ("\\"))
{
path=path+File.separator;
}
caching = TurbineResources.getBoolean (
TurbineServices.SERVICE_PREFIX +
XSLTService.SERVICE_NAME + ".cache");
setInit(true);
}
/**
* Get a valid and existing filename from a template name.
* The extension is removed and replaced with .xsl. If this
* file does not exist the method attempts to find default.xsl.
* If it fails to find default.xsl it returns null.
*/
protected String getFileName (String templateName)
{
// First we chop of the existing extension
int colon = templateName.lastIndexOf (".");
if (colon > 0)
{
templateName = templateName.substring (0,colon);
}
// Now we try to find the file ...
File f = new File (path+templateName+".xsl");
if (f.exists())
{
return path+templateName+".xsl";
}
else
{
// ... or the default file
f = new File (path+"default.xsl");
if (f.exists())
{
return path+"default.xsl";
}
else
{
return null;
}
}
}
/**
* Compile a new StylesheetRoot from an input file.
*/
protected StylesheetRoot compileStylesheetRoot (String source) throws Exception
{
XSLTProcessor processor = XSLTProcessorFactory.getProcessor();
XSLTInputSource xslin = new XSLTInputSource("file:///"+source);
StylesheetRoot root = processor.processStylesheet(xslin);
return root;
}
/**
* Retrieves a StylesheetRoot. If caching is switched on the
* first attempt is to load the StylesheetRoot from the cache.
* If caching is switched of or if the Stylesheet is not found
* in the cache a new StyleSheetRoot is compiled from an input
* file.
* <p>
* This method is synchronized on the xsl cache so that a thread
* does not attempt to load a StyleSheetRoot from the cache while
* it is still being compiled.
*/
protected StylesheetRoot getStylesheetRoot(String xslName) throws Exception
{
synchronized (cache)
{
if (caching && cache.containsKey (xslName))
{
return (StylesheetRoot)cache.get(xslName);
}
String fn = getFileName (xslName);
if (fn == null) return null;
StylesheetRoot sr = compileStylesheetRoot (fn);
if (caching)
{
cache.put (xslName,sr);
}
return sr;
}
}
protected void transform (String xslName, XSLTProcessor processor, XSLTInputSource xmlin, XSLTResultTarget xmlout) throws Exception
{
StylesheetRoot sr = getStylesheetRoot(xslName);
// If there is no stylesheet we just echo the xml
if (sr == null)
{
String line;
BufferedReader br = new BufferedReader (xmlin.getCharacterStream());
BufferedWriter bw = new BufferedWriter (xmlout.getCharacterStream());
line = br.readLine();
while (line != null)
{
try
{
bw.write (line);
line = br.readLine();
}
finally
{
bw.flush();
}
}
}
else
{
processor.setStylesheet (sr);
processor.process(xmlin, null, xmlout);
}
}
/**
* Execute an xslt
*/
public void transform (String xslName, Reader in, Writer out) throws Exception
{
XSLTProcessor processor = XSLTProcessorFactory.getProcessor();
XSLTInputSource xmlin = new XSLTInputSource(in);
XSLTResultTarget xmlout = new XSLTResultTarget(out);
transform (xslName,processor,xmlin,xmlout);
}
/**
* Execute an xslt
*/
public String transform (String xslName, Reader in) throws Exception
{
StringWriter sw = new StringWriter();
transform (xslName,in,sw);
return sw.toString();
}
/**
* Execute an xslt
*/
public void transform (String xslName, org.w3c.dom.Node in, Writer out) throws Exception
{
XSLTProcessor processor = XSLTProcessorFactory.getProcessor();
XSLTInputSource xmlin = new XSLTInputSource(in);
XSLTResultTarget xmlout = new XSLTResultTarget(out);
transform (xslName,processor,xmlin,xmlout);
}
/**
* Execute an xslt
*/
public String transform (String xslName, org.w3c.dom.Node in) throws Exception
{
StringWriter sw = new StringWriter();
transform (xslName,in,sw);
return sw.toString();
}
}