/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2004 The Apache Software Foundation.

 *

 * Licensed 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,v 1.2.4.1 2005/09/10 18:14:09 jeffsuttor Exp $

 */

package com.sun.org.apache.xpath.internal;

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 com.sun.org.apache.xml.internal.dtm.DTM;

import com.sun.org.apache.xml.internal.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 com.sun.org.apache.xml.internal.dtm.DTMWSFilter)

      {

        dtm = xctxt.getDTM(source, false,

                          (com.sun.org.apache.xml.internal.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);

    }

  }

}