src/org/apache/xpath/SourceTreeManager.java - xalan-j - Git at Google

 /*
  * 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);
     }
   }
 }
	/*
	* 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);
	}
	}
	}