code: /*
   * 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.
   */
  /*
   * $Id$
   */
  package org.apache.xalan.lib;
  
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.util.Properties;
  import java.util.Vector;
  
  import javax.xml.transform.Templates;
  import javax.xml.transform.Transformer;
  import javax.xml.transform.TransformerConfigurationException;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.sax.SAXResult;
  import javax.xml.transform.sax.SAXTransformerFactory;
  import javax.xml.transform.sax.TransformerHandler;
  import javax.xml.transform.stream.StreamSource;
  
  import org.apache.xalan.extensions.XSLProcessorContext;
  import org.apache.xalan.templates.AVT;
  import org.apache.xalan.templates.ElemExtensionCall;
  import org.apache.xalan.templates.ElemLiteralResult;
  import org.apache.xalan.transformer.TransformerImpl;
  import org.apache.xml.utils.SystemIDResolver;
  import org.apache.xpath.XPathContext;
  
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXNotRecognizedException;
  import org.xml.sax.XMLReader;
  import org.xml.sax.helpers.XMLReaderFactory;
  /**
   */
  // Imported Serializer classes
  import org.apache.xml.serializer.Serializer;
  import org.apache.xml.serializer.SerializerFactory;
  
  /**
   * PipeDocument is a Xalan extension element to set stylesheet params and pipes an XML 
   * document through a series of 1 or more stylesheets.
   * PipeDocument is invoked from a stylesheet as the {@link #pipeDocument pipeDocument extension element}.
   * 
   * It is accessed by specifying a namespace URI as follows:
   * <pre>
   *    xmlns:pipe="http://xml.apache.org/xalan/PipeDocument"
   * </pre>
   *
   * @author Donald Leslie
   */
  public class PipeDocument
  {
  /**
   * Extension element for piping an XML document through a series of 1 or more transformations.
   * 
   * <pre>Common usage pattern: A stylesheet transforms a listing of documents to be
   * transformed into a TOC. For each document in the listing calls the pipeDocument
   * extension element to pipe that document through a series of 1 or more stylesheets 
   * to the desired output document.
   * 
   * Syntax:
   * &lt;xsl:stylesheet version="1.0"
   *                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
   *                xmlns:pipe="http://xml.apache.org/xalan/PipeDocument"
   *                extension-element-prefixes="pipe"&gt;
   * ...
   * &lt;pipe:pipeDocument   source="source.xml" target="target.xml"&gt;
   *   &lt;stylesheet href="ss1.xsl"&gt;
   *     &lt;param name="param1" value="value1"/&gt;
   *   &lt;/stylesheet&gt;
   *   &lt;stylesheet href="ss2.xsl"&gt;
   *     &lt;param name="param1" value="value1"/&gt;
   *     &lt;param name="param2" value="value2"/&gt;
   *   &lt;/stylesheet&gt;
   *   &lt;stylesheet href="ss1.xsl"/&gt;     
   * &lt;/pipe:pipeDocument&gt;
   * 
   * Notes:</pre>
   * <ul>
   *   <li>The base URI for the source attribute is the XML "listing" document.<li/>
   *   <li>The target attribute is taken as is (base is the current user directory).<li/>
   *   <li>The stylsheet containg the extension element is the base URI for the
   *   stylesheet hrefs.<li/>
   * </ul>
   */
    public void pipeDocument(XSLProcessorContext context, ElemExtensionCall elem)
  	  throws TransformerException, TransformerConfigurationException, 
           SAXException, IOException, FileNotFoundException	   
    {
  
        SAXTransformerFactory saxTFactory = (SAXTransformerFactory) TransformerFactory.newInstance();
        
        // XML doc to transform.
        String source =  elem.getAttribute("source", 
                                           context.getContextNode(),
                                           context.getTransformer());
        TransformerImpl transImpl = context.getTransformer();
  
        //Base URI for input doc, so base for relative URI to XML doc to transform.
        String baseURLOfSource = transImpl.getBaseURLOfSource();
        // Absolute URI for XML doc to transform.
        String absSourceURL = SystemIDResolver.getAbsoluteURI(source, baseURLOfSource);      
  
        // Transformation target
        String target =  elem.getAttribute("target", 
                                           context.getContextNode(),
                                           context.getTransformer());
        
        XPathContext xctxt = context.getTransformer().getXPathContext();
        int xt = xctxt.getDTMHandleFromNode(context.getContextNode());
   
        // Get System Id for stylesheet; to be used to resolve URIs to other stylesheets.
        String sysId = elem.getSystemId();
        
        NodeList ssNodes = null;
        NodeList paramNodes = null;
        Node ssNode = null;
        Node paramNode = null;
        if (elem.hasChildNodes())
        {
          ssNodes = elem.getChildNodes();        
          // Vector to contain TransformerHandler for each stylesheet.
          Vector vTHandler = new Vector(ssNodes.getLength());
          
          // The child nodes of an extension element node are instances of
          // ElemLiteralResult, which requires does not fully support the standard
          // Node interface. Accordingly, some special handling is required (see below)
          // to get attribute values.
          for (int i = 0; i < ssNodes.getLength(); i++)
          {
            ssNode = ssNodes.item(i);
            if (ssNode.getNodeType() == Node.ELEMENT_NODE
                && ((Element)ssNode).getTagName().equals("stylesheet")
                && ssNode instanceof ElemLiteralResult)
            {
              AVT avt = ((ElemLiteralResult)ssNode).getLiteralResultAttribute("href");
              String href = avt.evaluate(xctxt,xt, elem);
              String absURI = SystemIDResolver.getAbsoluteURI(href, sysId);
              Templates tmpl = saxTFactory.newTemplates(new StreamSource(absURI));
              TransformerHandler tHandler = saxTFactory.newTransformerHandler(tmpl);
              Transformer trans = tHandler.getTransformer();
              
              // AddTransformerHandler to vector
              vTHandler.addElement(tHandler);
  
              paramNodes = ssNode.getChildNodes();
              for (int j = 0; j < paramNodes.getLength(); j++)
              {
                paramNode = paramNodes.item(j);
                if (paramNode.getNodeType() == Node.ELEMENT_NODE 
                    && ((Element)paramNode).getTagName().equals("param")
                    && paramNode instanceof ElemLiteralResult)
                {
                   avt = ((ElemLiteralResult)paramNode).getLiteralResultAttribute("name");
                   String pName = avt.evaluate(xctxt,xt, elem);
                   avt = ((ElemLiteralResult)paramNode).getLiteralResultAttribute("value");
                   String pValue = avt.evaluate(xctxt,xt, elem);
                   trans.setParameter(pName, pValue);
                 } 
               }
             }
           }
           usePipe(vTHandler, absSourceURL, target);
         }
    }
    /**
     * Uses a Vector of TransformerHandlers to pipe XML input document through
     * a series of 1 or more transformations. Called by {@link #pipeDocument}.
     * 
     * @param vTHandler Vector of Transformation Handlers (1 per stylesheet).
     * @param source absolute URI to XML input
     * @param target absolute path to transformation output.
     */
    public void usePipe(Vector vTHandler, String source, String target)
            throws TransformerException, TransformerConfigurationException, 
                   FileNotFoundException, IOException, SAXException, SAXNotRecognizedException
    {
      XMLReader reader = XMLReaderFactory.createXMLReader();
      TransformerHandler tHFirst = (TransformerHandler)vTHandler.firstElement();
      reader.setContentHandler(tHFirst);
      reader.setProperty("http://xml.org/sax/properties/lexical-handler", tHFirst);
      for (int i = 1; i < vTHandler.size(); i++)
      {
        TransformerHandler tHFrom = (TransformerHandler)vTHandler.elementAt(i-1);
        TransformerHandler tHTo = (TransformerHandler)vTHandler.elementAt(i);
        tHFrom.setResult(new SAXResult(tHTo));      
      }
      TransformerHandler tHLast = (TransformerHandler)vTHandler.lastElement();
      Transformer trans = tHLast.getTransformer();
      Properties outputProps = trans.getOutputProperties();
      Serializer serializer = SerializerFactory.getSerializer(outputProps);
      
      FileOutputStream out = new FileOutputStream(target);
      try 
      {
        serializer.setOutputStream(out);
        tHLast.setResult(new SAXResult(serializer.asContentHandler()));
        reader.parse(source);
      }
      finally 
      {
        // Always clean up the FileOutputStream,
        // even if an exception was thrown in the try block
        if (out != null)
          out.close();
      }    
    }
  }
  