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.xpath;
  
  import java.io.IOException;
  import java.util.Vector;
  
  import javax.xml.transform.Source;
  import javax.xml.transform.SourceLocator;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.URIResolver;
  import javax.xml.transform.sax.SAXSource;
  import javax.xml.transform.stream.StreamSource;
  
  import org.apache.xml.dtm.DTM;
  import org.apache.xml.utils.SystemIDResolver;
  
  import org.xml.sax.XMLReader;
  import org.xml.sax.helpers.XMLReaderFactory;
  
  /**
   * This class bottlenecks all management of source trees.  The methods
   * in this class should allow easy garbage collection of source
   * trees (not yet!), and should centralize parsing for those source trees.
   */
  public class SourceTreeManager
  {
  
    /** Vector of SourceTree objects that this manager manages. */
    private Vector m_sourceTree = new Vector();
  
    /**
     * Reset the list of SourceTree objects that this manager manages.
     *
     */
    public void reset()
    {
      m_sourceTree = new Vector();
    }
  
    /** The TrAX URI resolver used to obtain source trees. */
    URIResolver m_uriResolver;
  
    /**
     * Set an object that will be used to resolve URIs used in
     * document(), etc.
     * @param resolver An object that implements the URIResolver interface,
     * or null.
     */
    public void setURIResolver(URIResolver resolver)
    {
      m_uriResolver = resolver;
    }
  
    /**
     * Get the object that will be used to resolve URIs used in
     * document(), etc.
     * @return An object that implements the URIResolver interface,
     * or null.
     */
    public URIResolver getURIResolver()
    {
      return m_uriResolver;
    }
  
    /**
     * Given a document, find the URL associated with that document.
     * @param owner Document that was previously processed by this liaison.
     *
     * @return The base URI of the owner argument.
     */
    public String findURIFromDoc(int owner)
    {
      int n = m_sourceTree.size();
  
      for (int i = 0; i < n; i++)
      {
        SourceTree sTree = (SourceTree) m_sourceTree.elementAt(i);
  
        if (owner == sTree.m_root)
          return sTree.m_url;
      }
  
      return null;
    }
  
    /**
     * This will be called by the processor when it encounters
     * an xsl:include, xsl:import, or document() function.
     *
     * @param base The base URI that should be used.
     * @param urlString Value from an xsl:import or xsl:include's href attribute,
     * or a URI specified in the document() function.
     * 
     * @return a Source that can be used to process the resource.
     *
     * @throws IOException
     * @throws TransformerException
     */
    public Source resolveURI(
            String base, String urlString, SourceLocator locator)
              throws TransformerException, IOException
    {
  
      Source source = null;
  
      if (null != m_uriResolver)
      {
        source = m_uriResolver.resolve(urlString, base);
      }
  
      if (null == source)
      {
        String uri = SystemIDResolver.getAbsoluteURI(urlString, base);
  
        source = new StreamSource(uri);
      }
  
      return source;
    }
  
    /** JJK: Support  <?xalan:doc_cache_off?> kluge in ElemForEach.
     * TODO: This function is highly dangerous. Cache management must be improved.
     *
     * @param n The node to remove.
     */
    public void removeDocumentFromCache(int n)
    {
      if(DTM.NULL ==n)
        return;
      for(int i=m_sourceTree.size()-1;i>=0;--i)
      {
        SourceTree st=(SourceTree)m_sourceTree.elementAt(i);
        if(st!=null && st.m_root==n)
        {
  	m_sourceTree.removeElementAt(i);
  	return;
        }
      }
    }
    
  
  
    /**
     * Put the source tree root node in the document cache.
     * TODO: This function needs to be a LOT more sophisticated.
     *
     * @param n The node to cache.
     * @param source The Source object to cache.
     */
    public void putDocumentInCache(int n, Source source)
    {
  
      int cachedNode = getNode(source);
  
      if (DTM.NULL != cachedNode)
      {
        if (!(cachedNode == n))
          throw new RuntimeException(
            "Programmer's Error!  "
            + "putDocumentInCache found reparse of doc: "
            + source.getSystemId());
        return;
      }
      if (null != source.getSystemId())
      {
        m_sourceTree.addElement(new SourceTree(n, source.getSystemId()));
      }
    }
  
    /**
     * Given a Source object, find the node associated with it.
     *
     * @param source The Source object to act as the key.
     *
     * @return The node that is associated with the Source, or null if not found.
     */
    public int getNode(Source source)
    {
  
  //    if (source instanceof DOMSource)
  //      return ((DOMSource) source).getNode();
  
      // TODO: Not sure if the BaseID is really the same thing as the ID.
      String url = source.getSystemId();
  
      if (null == url)
        return DTM.NULL;
  
      int n = m_sourceTree.size();
  
      // System.out.println("getNode: "+n);
      for (int i = 0; i < n; i++)
      {
        SourceTree sTree = (SourceTree) m_sourceTree.elementAt(i);
  
        // System.out.println("getNode -         url: "+url);
        // System.out.println("getNode - sTree.m_url: "+sTree.m_url);
        if (url.equals(sTree.m_url))
          return sTree.m_root;
      }
  
      // System.out.println("getNode - returning: "+node);
      return DTM.NULL;
    }
  
    /**
     * Get the source tree from the a base URL and a URL string.
     *
     * @param base The base URI to use if the urlString is relative.
     * @param urlString An absolute or relative URL string.
     * @param locator The location of the caller, for diagnostic purposes.
     *
     * @return should be a non-null reference to the node identified by the 
     * base and urlString.
     *
     * @throws TransformerException If the URL can not resolve to a node.
     */
    public int getSourceTree(
            String base, String urlString, SourceLocator locator, XPathContext xctxt)
              throws TransformerException
    {
  
      // System.out.println("getSourceTree");
      try
      {
        Source source = this.resolveURI(base, urlString, locator);
  
        // System.out.println("getSourceTree - base: "+base+", urlString: "+urlString+", source: "+source.getSystemId());
        return getSourceTree(source, locator, xctxt);
      }
      catch (IOException ioe)
      {
        throw new TransformerException(ioe.getMessage(), locator, ioe);
      }
  
      /* catch (TransformerException te)
       {
         throw new TransformerException(te.getMessage(), locator, te);
       }*/
    }
  
    /**
     * Get the source tree from the input source.
     *
     * @param source The Source object that should identify the desired node.
     * @param locator The location of the caller, for diagnostic purposes.
     *
     * @return non-null reference to a node.
     *
     * @throws TransformerException if the Source argument can't be resolved to 
     *         a node.
     */
    public int getSourceTree(Source source, SourceLocator locator, XPathContext xctxt)
            throws TransformerException
    {
  
      int n = getNode(source);
  
      if (DTM.NULL != n)
        return n;
  
      n = parseToNode(source, locator, xctxt);
  
      if (DTM.NULL != n)
        putDocumentInCache(n, source);
  
      return n;
    }
  
    /**
     * Try to create a DOM source tree from the input source.
     *
     * @param source The Source object that identifies the source node.
     * @param locator The location of the caller, for diagnostic purposes.
     *
     * @return non-null reference to node identified by the source argument.
     *
     * @throws TransformerException if the source argument can not be resolved 
     *         to a source node.
     */
    public int parseToNode(Source source, SourceLocator locator, XPathContext xctxt)
            throws TransformerException
    {
  
      try
      {      
        Object xowner = xctxt.getOwnerObject();
        DTM dtm;
        if(null != xowner && xowner instanceof org.apache.xml.dtm.DTMWSFilter)
        {
          dtm = xctxt.getDTM(source, false, 
                            (org.apache.xml.dtm.DTMWSFilter)xowner, false, true);
        }
        else
        {
          dtm = xctxt.getDTM(source, false, null, false, true);
        }
        return dtm.getDocument();
      }
      catch (Exception e)
      {
        //e.printStackTrace();
        throw new TransformerException(e.getMessage(), locator, e);
      }
  
    }
  
    /**
     * This method returns the SAX2 parser to use with the InputSource
     * obtained from this URI.
     * It may return null if any SAX2-conformant XML parser can be used,
     * or if getInputSource() will also return null. The parser must
     * be free for use (i.e.
     * not currently in use for another parse().
     *
     * @param inputSource The value returned from the URIResolver.
     * @return a SAX2 XMLReader to use to resolve the inputSource argument.
     * @param locator The location of the original caller, for diagnostic purposes.
     *
     * @throws TransformerException if the reader can not be created.
     */
    public static XMLReader getXMLReader(Source inputSource, SourceLocator locator)
            throws TransformerException
    {
  
      try
      {
        XMLReader reader = (inputSource instanceof SAXSource)
                           ? ((SAXSource) inputSource).getXMLReader() : null;
                           
        if (null == reader)
        {
          try {
            javax.xml.parsers.SAXParserFactory factory=
                javax.xml.parsers.SAXParserFactory.newInstance();
            factory.setNamespaceAware( true );
            javax.xml.parsers.SAXParser jaxpParser=
                factory.newSAXParser();
            reader=jaxpParser.getXMLReader();
            
          } catch( javax.xml.parsers.ParserConfigurationException ex ) {
            throw new org.xml.sax.SAXException( ex );
          } catch( javax.xml.parsers.FactoryConfigurationError ex1 ) {
              throw new org.xml.sax.SAXException( ex1.toString() );
          } catch( NoSuchMethodError ex2 ) {
          }
          catch (AbstractMethodError ame){}
          if(null == reader)
            reader = XMLReaderFactory.createXMLReader();
        }
  
        try
        {
          reader.setFeature("http://xml.org/sax/features/namespace-prefixes",
                            true);
        }
        catch (org.xml.sax.SAXException se)
        {
  
          // What can we do?
          // TODO: User diagnostics.
        }
  
        return reader;
      }
      catch (org.xml.sax.SAXException se)
      {
        throw new TransformerException(se.getMessage(), locator, se);
      }
    }
  }
  