http://xml.apache.org/xalan-j/: Serializer to write out XML, HTML etc. as a stream of characters from an input DOM or from input SAX events. (The Apache Software Foundation) 
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 * Licensed to the Apache Software Foundation (ASF) under one
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 * 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: SourceTreeManager.java 468655 2006-10-28 07:12:06Z minchau $
 */
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.

/**
 * 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. 
/** Vector of SourceTree objects that this manager manages. */
  private Vector m_sourceTree = new Vector();

  
Reset the list of SourceTree objects that this manager manages.

/**
   * 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. 
/** 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.

Params:
  • resolver – An object that implements the URIResolver interface,
or null.
/**
   * 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.

Returns:An object that implements the URIResolver interface,
or null.
/**
   * 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.

Params:
  • owner – Document that was previously processed by this liaison.
Returns:The base URI of the owner argument.
/**
   * 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.

Params:
  • base – The base URI that should be used.
  • urlString – Value from an xsl:import or xsl:include's href attribute,
or a URI specified in the document() function.
Throws:
Returns:a Source that can be used to process the resource.
/**
   * 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   kluge in ElemForEach.
TODO: This function is highly dangerous. Cache management must be improved.

Params:
  • n – The node to remove.
/** 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.

Params:
  • n – The node to cache.
  • source – The Source object to cache.
/**
   * 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.

Params:
  • source – The Source object to act as the key.
Returns:The node that is associated with the Source, or null if not found.
/**
   * 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.

Params:
  • base – The base URI to use if the urlString is relative.
  • urlString – An absolute or relative URL string.
  • locator – The location of the caller, for diagnostic purposes.
Throws:
Returns:should be a non-null reference to the node identified by the 
base and urlString.
/**
   * 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.

Params:
  • source – The Source object that should identify the desired node.
  • locator – The location of the caller, for diagnostic purposes.
Throws:
Returns:non-null reference to a node.
/**
   * 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.

Params:
  • source – The Source object that identifies the source node.
  • locator – The location of the caller, for diagnostic purposes.
Throws:
Returns:non-null reference to node identified by the source argument.
/**
   * 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().

Params:
  • inputSource – The value returned from the URIResolver.
  • locator – The location of the original caller, for diagnostic purposes.
Throws:
Returns:a SAX2 XMLReader to use to resolve the inputSource argument.
/**
   * 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);
    }
  }
}