dombuilder.java

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/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xml.utils;

import org.apache.xalan.res.XSLMessages;
import org.apache.xpath.res.XPATHErrorResources;
import org.apache.xml.utils.NodeVector;
import java.util.Stack;

import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.Attributes;

import org.w3c.dom.*;  // we pretty much use everything in the DOM here.

/**
 * <meta name="usage" content="general"/>
 * This class takes SAX events (in addition to some extra events
 * that SAX doesn't handle yet) and adds the result to a document
 * or document fragment.
 */
public class DOMBuilder
        implements ContentHandler, LexicalHandler
{

  /** Root document          */
  public Document m_doc;

  /** Current node           */
  protected Node m_currentNode = null;

  /** First node of document fragment or null if not a DocumentFragment     */
  public DocumentFragment m_docFrag = null;

  /** Vector of element nodes          */
  protected Stack m_elemStack = new Stack();

  /**
   * DOMBuilder instance constructor... it will add the DOM nodes
   * to the document fragment.
   *
   * @param doc Root document
   * @param node Current node
   */
  public DOMBuilder(Document doc, Node node)
  {
    m_doc = doc;
    m_currentNode = node;
  }

  /**
   * DOMBuilder instance constructor... it will add the DOM nodes
   * to the document fragment.
   *
   * @param doc Root document
   * @param docFrag Document fragment
   */
  public DOMBuilder(Document doc, DocumentFragment docFrag)
  {
    m_doc = doc;
    m_docFrag = docFrag;
  }

  /**
   * DOMBuilder instance constructor... it will add the DOM nodes
   * to the document.
   *
   * @param doc Root document
   */
  public DOMBuilder(Document doc)
  {
    m_doc = doc;
  }

  /**
   * Get the root node of the DOM being created.  This
   * is either a Document or a DocumentFragment.
   *
   * @return The root document or document fragment if not null
   */
  public Node getRootNode()
  {
    return (null != m_docFrag) ? (Node) m_docFrag : (Node) m_doc;
  }

  /**
   * Get the node currently being processed.
   *
   * @return the current node being processed
   */
  public Node getCurrentNode()
  {
    return m_currentNode;
  }

  /**
   * Return null since there is no Writer for this class.
   *
   * @return null
   */
  public java.io.Writer getWriter()
  {
    return null;
  }

  /**
   * Append a node to the current container.
   *
   * @param newNode New node to append
   */
  protected void append(Node newNode) throws org.xml.sax.SAXException
  {

    Node currentNode = m_currentNode;

    if (null != currentNode)
    {
      currentNode.appendChild(newNode);

      // System.out.println(newNode.getNodeName());
    }
    else if (null != m_docFrag)
    {
      m_docFrag.appendChild(newNode);
    }
    else
    {
      boolean ok = true;
      short type = newNode.getNodeType();

      if (type == Node.TEXT_NODE)
      {
        String data = newNode.getNodeValue();

        if ((null != data) && (data.trim().length() > 0))
        {
          throw new org.xml.sax.SAXException(
            XSLMessages.createXPATHMessage(
              XPATHErrorResources.ER_CANT_OUTPUT_TEXT_BEFORE_DOC, null));  //"Warning: can't output text before document element!  Ignoring...");
        }

        ok = false;
      }
      else if (type == Node.ELEMENT_NODE)
      {
        if (m_doc.getDocumentElement() != null)
        {
          throw new org.xml.sax.SAXException(
            XSLMessages.createXPATHMessage(
              XPATHErrorResources.ER_CANT_HAVE_MORE_THAN_ONE_ROOT, null));  //"Can't have more than one root on a DOM!");
        }
      }

      if (ok)
        m_doc.appendChild(newNode);
    }
  }

  /**
   * Receive an object for locating the origin of SAX document events.
   *
   * <p>SAX parsers are strongly encouraged (though not absolutely
   * required) to supply a locator: if it does so, it must supply
   * the locator to the application by invoking this method before
   * invoking any of the other methods in the ContentHandler
   * interface.</p>
   *
   * <p>The locator allows the application to determine the end
   * position of any document-related event, even if the parser is
   * not reporting an error.  Typically, the application will
   * use this information for reporting its own errors (such as
   * character content that does not match an application's
   * business rules).  The information returned by the locator
   * is probably not sufficient for use with a search engine.</p>
   *
   * <p>Note that the locator will return correct information only
   * during the invocation of the events in this interface.  The
   * application should not attempt to use it at any other time.</p>
   *
   * @param locator An object that can return the location of
   *                any SAX document event.
   * @see org.xml.sax.Locator
   */
  public void setDocumentLocator(Locator locator)
  {

    // No action for the moment.
  }

  /**
   * Receive notification of the beginning of a document.
   *
   * <p>The SAX parser will invoke this method only once, before any
   * other methods in this interface or in DTDHandler (except for
   * setDocumentLocator).</p>
   */
  public void startDocument() throws org.xml.sax.SAXException
  {

    // No action for the moment.
  }

  /**
   * Receive notification of the end of a document.
   *
   * <p>The SAX parser will invoke this method only once, and it will
   * be the last method invoked during the parse.  The parser shall
   * not invoke this method until it has either abandoned parsing
   * (because of an unrecoverable error) or reached the end of
   * input.</p>
   */
  public void endDocument() throws org.xml.sax.SAXException
  {

    // No action for the moment.
  }

  /**
   * Receive notification of the beginning of an element.
   *
   * <p>The Parser will invoke this method at the beginning of every
   * element in the XML document; there will be a corresponding
   * endElement() event for every startElement() event (even when the
   * element is empty). All of the element's content will be
   * reported, in order, before the corresponding endElement()
   * event.</p>
   *
   * <p>If the element name has a namespace prefix, the prefix will
   * still be attached.  Note that the attribute list provided will
   * contain only attributes with explicit values (specified or
   * defaulted): #IMPLIED attributes will be omitted.</p>
   *
   *
   * @param ns The namespace of the node
   * @param localName The local part of the qualified name 
   * @param name The element name.
   * @param atts The attributes attached to the element, if any.
   * @see #endElement
   * @see org.xml.sax.Attributes
   */
  public void startElement(
          String ns, String localName, String name, Attributes atts)
            throws org.xml.sax.SAXException
  {

    Element elem;

	// Note that the namespace-aware call must be used to correctly
	// construct a Level 2 DOM, even for non-namespaced nodes.
    if ((null == ns) || (ns.length() == 0))
      elem = m_doc.createElementNS(null,name);
    else
      elem = m_doc.createElementNS(ns, name);

    append(elem);

    try
    {
      int nAtts = atts.getLength();
  
      if (0 != nAtts)
      {
        for (int i = 0; i < nAtts; i++)
        {
  
          //System.out.println("type " + atts.getType(i) + " name " + atts.getLocalName(i) );
          // First handle a possible ID attribute
          if (atts.getType(i).equalsIgnoreCase("ID"))
            setIDAttribute(atts.getValue(i), elem);
  
          String attrNS = atts.getURI(i);
          
          String attrQName = atts.getQName(i);
          if((attrQName.equals("xmlns") || attrQName.startsWith("xmlns:")) )
          {
            elem.setAttributeNS("http://www.w3.org/2000/xmlns/",attrQName, atts.getValue(i));
          }
          else
          {
             elem.setAttributeNS(atts.getURI(i),attrQName, atts.getValue(i));
          }
        }
      }
      
      // append(elem);
  
      m_elemStack.push(elem);
  
      m_currentNode = elem;
      
      // append(elem);
    }
    catch(java.lang.Exception de)
    {
      // de.printStackTrace();
      throw new org.xml.sax.SAXException(de);
    }
    
  }

  /**
   * Receive notification of the end of an element.
   *
   * <p>The SAX parser will invoke this method at the end of every
   * element in the XML document; there will be a corresponding
   * startElement() event for every endElement() event (even when the
   * element is empty).</p>
   *
   * <p>If the element name has a namespace prefix, the prefix will
   * still be attached to the name.</p>
   *
   *
   * @param ns the namespace of the element
   * @param localName The local part of the qualified name of the element
   * @param name The element name
   */
  public void endElement(String ns, String localName, String name)
          throws org.xml.sax.SAXException
  {
    m_elemStack.pop();
    m_currentNode = m_elemStack.isEmpty() ? null : (Node)m_elemStack.peek();
  }