/*

  * 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.

  */

 package org.apache.any23.extractor.rdfa;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import org.w3c.dom.Document;

 import javax.xml.transform.Transformer;

 import javax.xml.transform.TransformerConfigurationException;

 import javax.xml.transform.TransformerException;

 import javax.xml.transform.TransformerFactory;

 import javax.xml.transform.dom.DOMSource;

 import javax.xml.transform.stream.StreamResult;

 import javax.xml.transform.stream.StreamSource;

 import java.io.InputStream;

 import java.io.Writer;

 import java.util.HashMap;

 import java.util.Map;

 /**

  * An XSLT stylesheet loaded from an InputStream, can be applied

  * to DOM trees and writes the result to a {@link Writer}.

  *

  * @author Gabriele Renzi

  * @author Richard Cyganiak (richard@cyganiak.de)

  */

 public class XSLTStylesheet {

     private final static Logger log = LoggerFactory.getLogger(XSLTStylesheet.class);

     private final Transformer transformer;

     public XSLTStylesheet(InputStream xsltFile) {

         try {

             transformer = TransformerFactory.newInstance().newTransformer(new StreamSource(xsltFile));

         } catch (TransformerConfigurationException e) {

             throw new RuntimeException("Should not happen, we use the default configuration", e);

         }

     }

     /**

      * Applies the XSLT transformation

      * @param document where apply the transformation

      * @param output the {@link java.io.Writer} where write on

      */

     public synchronized void applyTo(Document document, Writer output)

             throws XSLTStylesheetException {

         this.applyTo(document, output, new HashMap<String, String>());

     }

     /**

      * Applies the XSLT transformation

      * @param document where apply the transformation

      * @param output the {@link java.io.Writer} where write on

      * @param parameters the parameters to be passed to {@link Transformer}.

      *              Pass an empty {@link Map} if no parameters are foreseen.

      */

     public synchronized void applyTo(Document document, Writer output,

                                      Map<String, String> parameters) throws XSLTStylesheetException {

         for(String parameterKey : parameters.keySet()) {

             transformer.setParameter(parameterKey, parameters.get(parameterKey));

         }

         try {

             transformer.transform(

                     new DOMSource(

                             document,

                             document.getBaseURI()

                     ),

                     new StreamResult(output)

             );

         } catch (TransformerException te) {

             log.error("------ BEGIN XSLT Transformer Exception ------");

             log.error("Exception in XSLT Stylesheet transformation.", te);

             log.error("Input DOM node:", document);

             log.error("Input DOM node getBaseURI:", document.getBaseURI());

             log.error("Output writer:", output);

             log.error("------ END XSLT Transformer Exception ------");

             throw new XSLTStylesheetException(" An error occurred during the XSLT transformation", te);

         }

     }

 }