/*
 * 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.
 */
package nokogiri.internals.dom2dtm;

import javax.xml.transform.SourceLocator;
import javax.xml.transform.dom.DOMSource;

import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMManager;
import org.apache.xml.dtm.DTMWSFilter;
import org.apache.xml.dtm.ref.DTMDefaultBaseIterators;
import org.apache.xml.dtm.ref.DTMManagerDefault;
import org.apache.xml.dtm.ref.ExpandedNameTable;
import org.apache.xml.dtm.ref.IncrementalSAXSource;
import org.apache.xml.res.XMLErrorResources;
import org.apache.xml.res.XMLMessages;
import org.apache.xml.utils.FastStringBuffer;
import org.apache.xml.utils.QName;
import org.apache.xml.utils.StringBufferPool;
import org.apache.xml.utils.TreeWalker;
import org.apache.xml.utils.XMLCharacterRecognizer;
import org.apache.xml.utils.XMLString;
import org.apache.xml.utils.XMLStringFactory;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.Entity;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.xml.sax.ContentHandler;

/** The <code>DOM2DTM</code> class serves up a DOM's contents via the
 * DTM API.
 *
 * Note that it doesn't necessarily represent a full Document
 * tree. You can wrap a DOM2DTM around a specific node and its subtree
 * and the right things should happen. (I don't _think_ we currently
 * support DocumentFragment nodes as roots, though that might be worth
 * considering.)
 *
 * Note too that we do not currently attempt to track document
 * mutation. If you alter the DOM after wrapping DOM2DTM around it,
 * all bets are off.
 * */
public class DOM2DTM extends DTMDefaultBaseIterators
{
//    static final boolean JJK_DEBUG=false;
//    static final boolean JJK_NEWCODE=true;

  /** Manifest constant
   */
  static final String NAMESPACE_DECL_NS = "http://www.w3.org/XML/1998/namespace";

  /** The current position in the DOM tree. Last node examined for
   * possible copying to DTM. */
  transient private Node m_pos;
  /** The current position in the DTM tree. Who children get appended to. */
  private int m_last_parent = 0;
  /** The current position in the DTM tree. Who children reference as their
   * previous sib. */
  private int m_last_kid = NULL;

  /** The top of the subtree.
   * %REVIEW%: 'may not be the same as m_context if "//foo" pattern.'
   * */
  transient private Node m_root;

  /** True iff the first element has been processed. This is used to control
   synthesis of the implied xml: namespace declaration node. */
  boolean m_processedFirstElement = false;

  /** true if ALL the nodes in the m_root subtree have been processed;
   * false if our incremental build has not yet finished scanning the
   * DOM tree.  */
  transient private boolean m_nodesAreProcessed;

  /** The node objects.  The instance part of the handle indexes
   * directly into this vector.  Each DTM node may actually be
   * composed of several DOM nodes (for example, if logically-adjacent
   * Text/CDATASection nodes in the DOM have been coalesced into a
   * single DTM Text node); this table points only to the first in
   * that sequence. */
  protected final java.util.List<Node> m_nodes = new java.util.ArrayList<Node>(12);

  /**
   * Construct a DOM2DTM object from a DOM node.
   *
   * @param mgr The DTMManager who owns this DTM.
   * @param domSource the DOM source that this DTM will wrap.
   * @param dtmIdentity The DTM identity ID for this DTM.
   * @param whiteSpaceFilter The white space filter for this DTM, which may
   *                         be null.
   * @param xstringfactory XMLString factory for creating character content.
   * @param doIndexing true if the caller considers it worth it to use
   *                   indexing schemes.
   */
  public
  DOM2DTM(DTMManager mgr, DOMSource domSource,
          int dtmIdentity, DTMWSFilter whiteSpaceFilter,
          XMLStringFactory xstringfactory,
          boolean doIndexing)
  {
    super(mgr, domSource, dtmIdentity, whiteSpaceFilter,
          xstringfactory, doIndexing);

    // Initialize DOM navigation
    m_pos = m_root = domSource.getNode();
    // Initialize DTM navigation
    m_last_parent = m_last_kid = NULL;
    m_last_kid = addNode(m_root, m_last_parent, m_last_kid, NULL);

    // Apparently the domSource root may not actually be the
    // Document node. If it's an Element node, we need to immediately
    // add its attributes. Adapted from nextNode().
    // %REVIEW% Move this logic into addNode and recurse? Cleaner!
    //
    // (If it's an EntityReference node, we're probably in
    // seriously bad trouble. For now
    // I'm just hoping nobody is ever quite that foolish... %REVIEW%)
    //
    // %ISSUE% What about inherited namespaces in this case?
    // Do we need to special-case initialize them into the DTM model?
    if (ELEMENT_NODE == m_root.getNodeType()) {
      NamedNodeMap attrs = m_root.getAttributes();
      int attrsize = (attrs == null) ? 0 : attrs.getLength();
      if (attrsize > 0) {
        int attrIndex = NULL; // start with no previous sib
        for (int i = 0; i < attrsize; ++i) {
          // No need to force nodetype in this case;
          // addNode() will take care of switching it from
          // Attr to Namespace if necessary.
          attrIndex = addNode(attrs.item(i), 0, attrIndex, NULL);
          m_firstch.setElementAt(DTM.NULL, attrIndex);
        }
        // Terminate list of attrs, and make sure they aren't
        // considered children of the element
        m_nextsib.setElementAt(DTM.NULL, attrIndex);

        // IMPORTANT: This does NOT change m_last_parent or m_last_kid!
      } // if attrs exist
    } //if(ELEMENT_NODE)

    // Initialize DTM-completed status
    m_nodesAreProcessed = false;
  }

  /**
   * Construct the node map from the node.
   *
   * @param node The node that is to be added to the DTM.
   * @param parentIndex The current parent index.
   * @param previousSibling The previous sibling index.
   * @param forceNodeType If not DTM.NULL, overrides the DOM node type.
   *	Used to force nodes to Text rather than CDATASection when their
   *	coalesced value includes ordinary Text nodes (current DTM behavior).
   *
   * @return The index identity of the node that was added.
   */
  protected int
  addNode(Node node, int parentIndex,
          int previousSibling, int forceNodeType)
  {
    int nodeIndex = m_nodes.size();

    // Have we overflowed a DTM Identity's addressing range?
    if (m_dtmIdent.size() == (nodeIndex >>> DTMManager.IDENT_DTM_NODE_BITS)) {
      try {
        if (m_mgr == null) {
          throw new ClassCastException();
        }

        // Handle as Extended Addressing
        DTMManagerDefault mgrD = (DTMManagerDefault)m_mgr;
        int id = mgrD.getFirstFreeDTMID();
        mgrD.addDTM(this, id, nodeIndex);
        m_dtmIdent.addElement(id << DTMManager.IDENT_DTM_NODE_BITS);
      } catch (ClassCastException e) {
        // %REVIEW% Wrong error message, but I've been told we're trying
        // not to add messages right not for I18N reasons.
        // %REVIEW% Should this be a Fatal Error?
        error(XMLMessages.createXMLMessage(XMLErrorResources.ER_NO_DTMIDS_AVAIL, null));//"No more DTM IDs are available";
      }
    }

    m_size++;
    // ensureSize(nodeIndex);

    int type;
    if (NULL == forceNodeType) {
      type = node.getNodeType();
    } else {
      type = forceNodeType;
    }

    // %REVIEW% The Namespace Spec currently says that Namespaces are
    // processed in a non-namespace-aware manner, by matching the
    // QName, even though there is in fact a namespace assigned to
    // these nodes in the DOM. If and when that changes, we will have
    // to consider whether we check the namespace-for-namespaces
    // rather than the node name.
    //
    // %TBD% Note that the DOM does not necessarily explicitly declare
    // all the namespaces it uses. DOM Level 3 will introduce a
    // namespace-normalization operation which reconciles that, and we
    // can request that users invoke it or otherwise ensure that the
    // tree is namespace-well-formed before passing the DOM to Xalan.
    // But if they don't, what should we do about it? We probably
    // don't want to alter the source DOM (and may not be able to do
    // so if it's read-only). The best available answer might be to
    // synthesize additional DTM Namespace Nodes that don't correspond
    // to DOM Attr Nodes.
    if (Node.ATTRIBUTE_NODE == type) {
      String name = node.getNodeName();

      if (name.startsWith("xmlns:") || name.equals("xmlns")) {
        type = DTM.NAMESPACE_NODE;
      }
    }

    m_nodes.add(node);

    m_firstch.setElementAt(NOTPROCESSED, nodeIndex);
    m_nextsib.setElementAt(NOTPROCESSED, nodeIndex);
    m_prevsib.setElementAt(previousSibling, nodeIndex);
    m_parent.setElementAt(parentIndex, nodeIndex);

    if (DTM.NULL != parentIndex &&
        type != DTM.ATTRIBUTE_NODE &&
        type != DTM.NAMESPACE_NODE) {
      // If the DTM parent had no children, this becomes its first child.
      if (NOTPROCESSED == m_firstch.elementAt(parentIndex)) {
        m_firstch.setElementAt(nodeIndex, parentIndex);
      }
    }

    String nsURI = node.getNamespaceURI();

    // Deal with the difference between Namespace spec and XSLT
    // definitions of local name. (The former says PIs don't have
    // localnames; the latter says they do.)
    String localName = (type == Node.PROCESSING_INSTRUCTION_NODE) ?
                       node.getNodeName() :
                       node.getLocalName();

    // Hack to make DOM1 sort of work...
    if (((type == Node.ELEMENT_NODE) || (type == Node.ATTRIBUTE_NODE))
        && null == localName) {
      localName = node.getNodeName();  // -sb
    }

    ExpandedNameTable exnt = m_expandedNameTable;

    // %TBD% Nodes created with the old non-namespace-aware DOM
    // calls createElement() and createAttribute() will never have a
    // localname. That will cause their expandedNameID to be just the
    // nodeType... which will keep them from being matched
    // successfully by name. Since the DOM makes no promise that
    // those will participate in namespace processing, this is
    // officially accepted as Not Our Fault. But it might be nice to
    // issue a diagnostic message!
    if (node.getLocalName() == null &&
        (type == Node.ELEMENT_NODE || type == Node.ATTRIBUTE_NODE)) {
      // warning("DOM 'level 1' node "+node.getNodeName()+" won't be mapped properly in DOM2DTM.");
    }

    int expandedNameID = (null != localName)
                         ? exnt.getExpandedTypeID(nsURI, localName, type) :
                         exnt.getExpandedTypeID(type);

    m_exptype.setElementAt(expandedNameID, nodeIndex);

    indexNode(expandedNameID, nodeIndex);

    if (DTM.NULL != previousSibling) {
      m_nextsib.setElementAt(nodeIndex, previousSibling);
    }

    // This should be done after m_exptype has been set, and probably should
    // always be the last thing we do
    if (type == DTM.NAMESPACE_NODE) {
      declareNamespaceInContext(parentIndex, nodeIndex);
    }

    return nodeIndex;
  }

  /**
   * Get the number of nodes that have been added.
   */
  public int
  getNumberOfNodes()
  {
    return m_nodes.size();
  }

  /**
   * This method iterates to the next node that will be added to the table.
   * Each call to this method adds a new node to the table, unless the end
   * is reached, in which case it returns null.
   *
   * @return The true if a next node is found or false if
   *         there are no more nodes.
   */
  protected boolean
  nextNode()
  {
    // Non-recursive one-fetch-at-a-time depth-first traversal with
    // attribute/namespace nodes and white-space stripping.
    // Navigating the DOM is simple, navigating the DTM is simple;
    // keeping track of both at once is a trifle baroque but at least
    // we've avoided most of the special cases.
    if (m_nodesAreProcessed) {
      return false;
    }

    // %REVIEW% Is this local copy Really Useful from a performance
    // point of view?  Or is this a false micro-optimization?
    Node pos = m_pos;
    Node next = null;
    int nexttype = NULL;

    // Navigate DOM tree
    do {
      // Look down to first child.
      if (pos.hasChildNodes()) {
        next = pos.getFirstChild();

        // %REVIEW% There's probably a more elegant way to skip
        // the doctype. (Just let it go and Suppress it?
        if (next != null && DOCUMENT_TYPE_NODE == next.getNodeType()) {
          next = next.getNextSibling();
        }

        // Push DTM context -- except for children of Entity References,
        // which have no DTM equivalent and cause no DTM navigation.
        if (ENTITY_REFERENCE_NODE != pos.getNodeType()) {
          m_last_parent = m_last_kid;
          m_last_kid = NULL;
          // Whitespace-handler context stacking
          if (null != m_wsfilter) {
            short wsv =
              m_wsfilter.getShouldStripSpace(makeNodeHandle(m_last_parent), this);
            boolean shouldStrip = (DTMWSFilter.INHERIT == wsv)
                                  ? getShouldStripWhitespace()
                                  : (DTMWSFilter.STRIP == wsv);
            pushShouldStripWhitespace(shouldStrip);
          } // if(m_wsfilter)
        }
      }

      // If that fails, look up and right (but not past root!)
      else {
        if (m_last_kid != NULL) {
          // Last node posted at this level had no more children
          // If it has _no_ children, we need to record that.
          if (m_firstch.elementAt(m_last_kid) == NOTPROCESSED) {
            m_firstch.setElementAt(NULL, m_last_kid);
          }
        }

        while (m_last_parent != NULL) {
          // %REVIEW% There's probably a more elegant way to
          // skip the doctype. (Just let it go and Suppress it?
          next = pos.getNextSibling();
          if (next != null && DOCUMENT_TYPE_NODE == next.getNodeType()) {
            next = next.getNextSibling();
          }

          if (next != null) {
            break;  // Found it!
          }

          // No next-sibling found. Pop the DOM.
          pos = pos.getParentNode();
//                    if(pos==null)
//                    {
//                        // %TBD% Should never arise, but I want to be sure of that...
//                        if(JJK_DEBUG)
//                        {
//                            System.out.println("***** DOM2DTM Pop Control Flow problem");
//                            for(;;); // Freeze right here!
//                        }
//                    }

          // The only parents in the DTM are Elements.  However,
          // the DOM could contain EntityReferences.  If we
          // encounter one, pop it _without_ popping DTM.
          if (pos != null && ENTITY_REFERENCE_NODE == pos.getNodeType()) {
//                        // Nothing needs doing
//                        if(JJK_DEBUG) System.out.println("***** DOM2DTM popping EntRef");
          } else {
            popShouldStripWhitespace();
            // Fix and pop DTM
            if (m_last_kid == NULL) {
              m_firstch.setElementAt(NULL, m_last_parent);  // Popping from an element
            } else {
              m_nextsib.setElementAt(NULL, m_last_kid);  // Popping from anything else
            }
            m_last_parent = m_parent.elementAt(m_last_kid = m_last_parent);
          }
        }
        if (m_last_parent == NULL) { next = null; }
      }

      if (next != null) { nexttype = next.getNodeType(); }

      // If it's an entity ref, advance past it.
      //
      // %REVIEW% Should we let this out the door and just suppress it?
      // More work, but simpler code, more likely to be correct, and
      // it doesn't happen very often. We'd get rid of the loop too.
      if (ENTITY_REFERENCE_NODE == nexttype) { pos = next; }
    } while (ENTITY_REFERENCE_NODE == nexttype);

    // Did we run out of the tree?
    if (next == null) {
      m_nextsib.setElementAt(NULL, 0);
      m_nodesAreProcessed = true;
      m_pos = null;

//            if(JJK_DEBUG)
//            {
//                System.out.println("***** DOM2DTM Crosscheck:");
//                for(int i=0;i<m_nodes.size();++i)
//                    System.out.println(i+":\t"+m_firstch.elementAt(i)+"\t"+m_nextsib.elementAt(i));
//            }

      return false;
    }

    // Text needs some special handling:
    //
    // DTM may skip whitespace. This is handled by the suppressNode flag, which
    // when true will keep the DTM node from being created.
    //
    // DTM only directly records the first DOM node of any logically-contiguous
    // sequence. The lastTextNode value will be set to the last node in the
    // contiguous sequence, and -- AFTER the DTM addNode -- can be used to
    // advance next over this whole block. Should be simpler than special-casing
    // the above loop for "Was the logically-preceding sibling a text node".
    //
    // Finally, a DTM node should be considered a CDATASection only if all the
    // contiguous text it covers is CDATASections. The first Text should
    // force DTM to Text.

    boolean suppressNode = false;
    Node lastTextNode = null;

    nexttype = next.getNodeType();

    // nexttype=pos.getNodeType();
    if (TEXT_NODE == nexttype || CDATA_SECTION_NODE == nexttype) {
      // If filtering, initially assume we're going to suppress the node
      suppressNode = ((null != m_wsfilter) && getShouldStripWhitespace());

      // Scan logically contiguous text (siblings, plus "flattening"
      // of entity reference boundaries).
      if (suppressNode) {
        Node n = next;
        while (n != null) {
          lastTextNode = n;
          // Any Text node means DTM considers it all Text
          if (TEXT_NODE == n.getNodeType()) { nexttype = TEXT_NODE; }
          // Any non-whitespace in this sequence blocks whitespace
          // suppression
          suppressNode &= XMLCharacterRecognizer.isWhiteSpace(n.getNodeValue());

          n = logicalNextDOMTextNode(n);
        }
      }
    }

    // Special handling for PIs: Some DOMs represent the XML
    // Declaration as a PI. This is officially incorrect, per the DOM
    // spec, but is considered a "wrong but tolerable" temporary
    // workaround pending proper handling of these fields in DOM Level
    // 3. We want to recognize and reject that case.
    else if (PROCESSING_INSTRUCTION_NODE == nexttype) {
      suppressNode = (pos.getNodeName().toLowerCase().equals("xml"));
    }


    if (!suppressNode) {
      // Inserting next. NOTE that we force the node type; for
      // coalesced Text, this records CDATASections adjacent to
      // ordinary Text as Text.
      int nextindex = addNode(next, m_last_parent, m_last_kid, nexttype);

      m_last_kid = nextindex;

      if (ELEMENT_NODE == nexttype) {
        int attrIndex = NULL; // start with no previous sib
        // Process attributes _now_, rather than waiting.
        // Simpler control flow, makes NS cache available immediately.
        NamedNodeMap attrs = next.getAttributes();
        int attrsize = (attrs == null) ? 0 : attrs.getLength();
        if (attrsize > 0) {
          for (int i = 0; i < attrsize; ++i) {
            // No need to force nodetype in this case;
            // addNode() will take care of switching it from
            // Attr to Namespace if necessary.
            attrIndex = addNode(attrs.item(i), nextindex, attrIndex, NULL);
            m_firstch.setElementAt(DTM.NULL, attrIndex);

            // If the xml: prefix is explicitly declared
            // we don't need to synthesize one.
            //
            // NOTE that XML Namespaces were not originally
            // defined as being namespace-aware (grrr), and
            // while the W3C is planning to fix this it's
            // safer for now to test the QName and trust the
            // parsers to prevent anyone from redefining the
            // reserved xmlns: prefix
            if (!m_processedFirstElement
                && "xmlns:xml".equals(attrs.item(i).getNodeName())) {
              m_processedFirstElement = true;
            }
          }
          // Terminate list of attrs, and make sure they aren't
          // considered children of the element
        } // if attrs exist
        if (!m_processedFirstElement) {
          // The DOM might not have an explicit declaration for the
          // implicit "xml:" prefix, but the XPath data model
          // requires that this appear as a Namespace Node so we
          // have to synthesize one. You can think of this as
          // being a default attribute defined by the XML
          // Namespaces spec rather than by the DTD.
          attrIndex = addNode(new DOM2DTMdefaultNamespaceDeclarationNode(
                                (Element)next, "xml", NAMESPACE_DECL_NS,
                                makeNodeHandle(((attrIndex == NULL) ? nextindex : attrIndex) + 1)
                              ),
                              nextindex, attrIndex, NULL);
          m_firstch.setElementAt(DTM.NULL, attrIndex);
          m_processedFirstElement = true;
        }
        if (attrIndex != NULL) { m_nextsib.setElementAt(DTM.NULL, attrIndex); }
      } //if(ELEMENT_NODE)
    } // (if !suppressNode)

    // Text postprocessing: Act on values stored above
    //if(TEXT_NODE == nexttype || CDATA_SECTION_NODE == nexttype)
    //{
    // %TBD% If nexttype was forced to TEXT, patch the DTM node
    if (lastTextNode != null) { next = lastTextNode; }    // Advance the DOM cursor over contiguous text
    //}

    // Remember where we left off.
    m_pos = next;
    return true;
  }


  /**
   * Return an DOM node for the given node.
   *
   * @param nodeHandle The node ID.
   *
   * @return A node representation of the DTM node.
   */
  public Node
  getNode(int nodeHandle)
  {

    int identity = makeNodeIdentity(nodeHandle);

    return m_nodes.get(identity);
  }

  /**
   * Get a Node from an identity index.
   *
   * NEEDSDOC @param nodeIdentity
   *
   * NEEDSDOC ($objectName$) @return
   */
  protected Node
  lookupNode(int nodeIdentity)
  {
    return m_nodes.get(nodeIdentity);
  }

  /**
   * Get the next node identity value in the list, and call the iterator
   * if it hasn't been added yet.
   *
   * @param identity The node identity (index).
   * @return identity+1, or DTM.NULL.
   */
  protected int
  getNextNodeIdentity(int identity)
  {

    identity += 1;

    if (identity >= m_nodes.size()) {
      if (!nextNode()) {
        identity = DTM.NULL;
      }
    }

    return identity;
  }

  /**
   * Get the handle from a Node.
   * <p>%OPT% This will be pretty slow.</p>
   *
   * <p>%OPT% An XPath-like search (walk up DOM to root, tracking path;
   * walk down DTM reconstructing path) might be considerably faster
   * on later nodes in large documents. That might also imply improving
   * this call to handle nodes which would be in this DTM but
   * have not yet been built, which might or might not be a Good Thing.</p>
   *
   * %REVIEW% This relies on being able to test node-identity via
   * object-identity. DTM2DOM proxying is a great example of a case where
   * that doesn't work. DOM Level 3 will provide the isSameNode() method
   * to fix that, but until then this is going to be flaky.
   *
   * @param node A node, which may be null.
   *
   * @return The node handle or <code>DTM.NULL</code>.
   */
  public int
  getHandleFromNode(Node node)
  {
    if (null != node) {
      int len = m_nodes.size();
      boolean isMore;
      int i = 0;
      do {
        for (; i < len; i++) {
          if (m_nodes.get(i) == node) {
            return makeNodeHandle(i);
          }
        }

        isMore = nextNode();

        len = m_nodes.size();

      } while (isMore || i < len);
    }

    return DTM.NULL;
  }

  /** Get the handle from a Node. This is a more robust version of
   * getHandleFromNode, intended to be usable by the public.
   *
   * <p>%OPT% This will be pretty slow.</p>
   *
   * %REVIEW% This relies on being able to test node-identity via
   * object-identity. DTM2DOM proxying is a great example of a case where
   * that doesn't work. DOM Level 3 will provide the isSameNode() method
   * to fix that, but until then this is going to be flaky.
   *
   * @param node A node, which may be null.
   *
   * @return The node handle or <code>DTM.NULL</code>.  */
  public int
  getHandleOfNode(Node node)
  {
    if (null != node) {
      // Is Node actually within the same document? If not, don't search!
      // This would be easier if m_root was always the Document node, but
      // we decided to allow wrapping a DTM around a subtree.
      if ((m_root == node) ||
          (m_root.getNodeType() == DOCUMENT_NODE &&
           m_root == node.getOwnerDocument()) ||
          (m_root.getNodeType() != DOCUMENT_NODE &&
           m_root.getOwnerDocument() == node.getOwnerDocument())
         ) {
        // If node _is_ in m_root's tree, find its handle
        //
        // %OPT% This check may be improved significantly when DOM
        // Level 3 nodeKey and relative-order tests become
        // available!
        for (Node cursor = node;
             cursor != null;
             cursor =
               (cursor.getNodeType() != ATTRIBUTE_NODE)
               ? cursor.getParentNode()
               : ((org.w3c.dom.Attr)cursor).getOwnerElement()) {
          if (cursor == m_root)
            // We know this node; find its handle.
          {
            return getHandleFromNode(node);
          }
        } // for ancestors of node
      } // if node and m_root in same Document
    } // if node!=null

    return DTM.NULL;
  }

  /**
   * Retrieves an attribute node by by qualified name and namespace URI.
   *
   * @param nodeHandle int Handle of the node upon which to look up this attribute..
   * @param namespaceURI The namespace URI of the attribute to
   *   retrieve, or null.
   * @param name The local name of the attribute to
   *   retrieve.
   * @return The attribute node handle with the specified name (
   *   <code>nodeName</code>) or <code>DTM.NULL</code> if there is no such
   *   attribute.
   */
  public int
  getAttributeNode(int nodeHandle, String namespaceURI,
                   String name)
  {

    // %OPT% This is probably slower than it needs to be.
    if (null == namespaceURI) {
      namespaceURI = "";
    }

    int type = getNodeType(nodeHandle);

    if (DTM.ELEMENT_NODE == type) {

      // Assume that attributes immediately follow the element.
      int identity = makeNodeIdentity(nodeHandle);

      while (DTM.NULL != (identity = getNextNodeIdentity(identity))) {
        // Assume this can not be null.
        type = _type(identity);

        // %REVIEW%
        // Should namespace nodes be retrievable DOM-style as attrs?
        // If not we need a separate function... which may be desirable
        // architecturally, but which is ugly from a code point of view.
        // (If we REALLY insist on it, this code should become a subroutine
        // of both -- retrieve the node, then test if the type matches
        // what you're looking for.)
        if (type == DTM.ATTRIBUTE_NODE || type == DTM.NAMESPACE_NODE) {
          Node node = lookupNode(identity);
          String nodeuri = node.getNamespaceURI();

          if (null == nodeuri) {
            nodeuri = "";
          }

          String nodelocalname = node.getLocalName();

          if (nodeuri.equals(namespaceURI) && name.equals(nodelocalname)) {
            return makeNodeHandle(identity);
          }
        }

        else { // if (DTM.NAMESPACE_NODE != type)
          break;
        }
      }
    }

    return DTM.NULL;
  }

  /**
   * Get the string-value of a node as a String object
   * (see http://www.w3.org/TR/xpath#data-model
   * for the definition of a node's string-value).
   *
   * @param nodeHandle The node ID.
   *
   * @return A string object that represents the string-value of the given node.
   */
  public XMLString
  getStringValue(int nodeHandle)
  {

    int type = getNodeType(nodeHandle);
    Node node = getNode(nodeHandle);
    // %TBD% If an element only has one text node, we should just use it
    // directly.
    if (DTM.ELEMENT_NODE == type || DTM.DOCUMENT_NODE == type
        || DTM.DOCUMENT_FRAGMENT_NODE == type) {
      FastStringBuffer buf = StringBufferPool.get();
      String s;

      try {
        getNodeData(node, buf);

        s = (buf.length() > 0) ? buf.toString() : "";
      } finally {
        StringBufferPool.free(buf);
      }

      return m_xstrf.newstr(s);
    } else if (TEXT_NODE == type || CDATA_SECTION_NODE == type) {
      // If this is a DTM text node, it may be made of multiple DOM text
      // nodes -- including navigating into Entity References. DOM2DTM
      // records the first node in the sequence and requires that we
      // pick up the others when we retrieve the DTM node's value.
      //
      // %REVIEW% DOM Level 3 is expected to add a "whole text"
      // retrieval method which performs this function for us.
      FastStringBuffer buf = StringBufferPool.get();
      while (node != null) {
        buf.append(node.getNodeValue());
        node = logicalNextDOMTextNode(node);
      }
      String s = (buf.length() > 0) ? buf.toString() : "";
      StringBufferPool.free(buf);
      return m_xstrf.newstr(s);
    } else {
      return m_xstrf.newstr(node.getNodeValue());
    }
  }

  /**
   * Determine if the string-value of a node is whitespace
   *
   * @param nodeHandle The node Handle.
   *
   * @return Return true if the given node is whitespace.
   */
  public boolean
  isWhitespace(int nodeHandle)
  {
    int type = getNodeType(nodeHandle);
    Node node = getNode(nodeHandle);
    if (TEXT_NODE == type || CDATA_SECTION_NODE == type) {
      // If this is a DTM text node, it may be made of multiple DOM text
      // nodes -- including navigating into Entity References. DOM2DTM
      // records the first node in the sequence and requires that we
      // pick up the others when we retrieve the DTM node's value.
      //
      // %REVIEW% DOM Level 3 is expected to add a "whole text"
      // retrieval method which performs this function for us.
      FastStringBuffer buf = StringBufferPool.get();
      while (node != null) {
        buf.append(node.getNodeValue());
        node = logicalNextDOMTextNode(node);
      }
      boolean b = buf.isWhitespace(0, buf.length());
      StringBufferPool.free(buf);
      return b;
    }
    return false;
  }

  /**
   * Retrieve the text content of a DOM subtree, appending it into a
   * user-supplied FastStringBuffer object. Note that attributes are
   * not considered part of the content of an element.
   * <p>
   * There are open questions regarding whitespace stripping.
   * Currently we make no special effort in that regard, since the standard
   * DOM doesn't yet provide DTD-based information to distinguish
   * whitespace-in-element-context from genuine #PCDATA. Note that we
   * should probably also consider xml:space if/when we address this.
   * DOM Level 3 may solve the problem for us.
   * <p>
   * %REVIEW% Actually, since this method operates on the DOM side of the
   * fence rather than the DTM side, it SHOULDN'T do
   * any special handling. The DOM does what the DOM does; if you want
   * DTM-level abstractions, use DTM-level methods.
   *
   * @param node Node whose subtree is to be walked, gathering the
   * contents of all Text or CDATASection nodes.
   * @param buf FastStringBuffer into which the contents of the text
   * nodes are to be concatenated.
   */
  protected static void
  getNodeData(Node node, FastStringBuffer buf)
  {

    switch (node.getNodeType()) {
      case Node.DOCUMENT_FRAGMENT_NODE :
      case Node.DOCUMENT_NODE :
      case Node.ELEMENT_NODE : {
        for (Node child = node.getFirstChild(); null != child;
             child = child.getNextSibling()) {
          getNodeData(child, buf);
        }
      }
      break;
      case Node.TEXT_NODE :
      case Node.CDATA_SECTION_NODE :
      case Node.ATTRIBUTE_NODE :	// Never a child but might be our starting node
        buf.append(node.getNodeValue());
        break;
      case Node.PROCESSING_INSTRUCTION_NODE :
        // warning(XPATHErrorResources.WG_PARSING_AND_PREPARING);
        break;
      default :
        // ignore
        break;
    }
  }

  /**
   * Given a node handle, return its DOM-style node name. This will
   * include names such as #text or #document.
   *
   * @param nodeHandle the id of the node.
   * @return String Name of this node, which may be an empty string.
   * %REVIEW% Document when empty string is possible...
   * %REVIEW-COMMENT% It should never be empty, should it?
   */
  public String
  getNodeName(int nodeHandle)
  {

    Node node = getNode(nodeHandle);

    // Assume non-null.
    return node.getNodeName();
  }

  /**
   * Given a node handle, return the XPath node name.  This should be
   * the name as described by the XPath data model, NOT the DOM-style
   * name.
   *
   * @param nodeHandle the id of the node.
   * @return String Name of this node, which may be an empty string.
   */
  public String
  getNodeNameX(int nodeHandle)
  {

    String name;
    short type = getNodeType(nodeHandle);

    switch (type) {
      case DTM.NAMESPACE_NODE : {
        Node node = getNode(nodeHandle);

        // assume not null.
        name = node.getNodeName();
        if (name.startsWith("xmlns:")) {
          name = QName.getLocalPart(name);
        } else if (name.equals("xmlns")) {
          name = "";
        }
      }
      break;
      case DTM.ATTRIBUTE_NODE :
      case DTM.ELEMENT_NODE :
      case DTM.ENTITY_REFERENCE_NODE :
      case DTM.PROCESSING_INSTRUCTION_NODE : {
        Node node = getNode(nodeHandle);

        // assume not null.
        name = node.getNodeName();
      }
      break;
      default :
        name = "";
    }

    return name;
  }

  /**
   * Given a node handle, return its XPath-style localname.
   * (As defined in Namespaces, this is the portion of the name after any
   * colon character).
   *
   * @param nodeHandle the id of the node.
   * @return String Local name of this node.
   */
  public String
  getLocalName(int nodeHandle)
  {
//        if(JJK_NEWCODE)
//        {
    int id = makeNodeIdentity(nodeHandle);
    if (NULL == id) { return null; }
    Node newnode = m_nodes.get(id);
    String newname = newnode.getLocalName();
    if (null == newname) {
      // XSLT treats PIs, and possibly other things, as having QNames.
      String qname = newnode.getNodeName();
      if ('#' == qname.charAt(0)) {
        //  Match old default for this function
        // This conversion may or may not be necessary
        newname = "";
      } else {
        int index = qname.indexOf(':');
        newname = (index < 0) ? qname : qname.substring(index + 1);
      }
    }
    return newname;
//        }
//        else
//        {
//            String name;
//            short type = getNodeType(nodeHandle);
//            switch (type)
//            {
//                case DTM.ATTRIBUTE_NODE :
//                case DTM.ELEMENT_NODE :
//                case DTM.ENTITY_REFERENCE_NODE :
//                case DTM.NAMESPACE_NODE :
//                case DTM.PROCESSING_INSTRUCTION_NODE :
//                {
//                    Node node = getNode(nodeHandle);
//
//                    // assume not null.
//                    name = node.getLocalName();
//
//                    if (null == name)
//                    {
//                        String qname = node.getNodeName();
//                        int index = qname.indexOf(':');
//
//                        name = (index < 0) ? qname : qname.substring(index + 1);
//                    }
//                }
//                break;
//                default :
//                    name = "";
//            }
//            return name;
//        }
  }

  /**
   * Given a namespace handle, return the prefix that the namespace decl is
   * mapping.
   * Given a node handle, return the prefix used to map to the namespace.
   *
   * <p> %REVIEW% Are you sure you want "" for no prefix?  </p>
   * <p> %REVIEW-COMMENT% I think so... not totally sure. -sb  </p>
   *
   * @param nodeHandle the id of the node.
   * @return String prefix of this node's name, or "" if no explicit
   * namespace prefix was given.
   */
  public String
  getPrefix(int nodeHandle)
  {

    String prefix;
    short type = getNodeType(nodeHandle);

    switch (type) {
      case DTM.NAMESPACE_NODE : {
        Node node = getNode(nodeHandle);

        // assume not null.
        String qname = node.getNodeName();
        int index = qname.indexOf(':');

        prefix = (index < 0) ? "" : qname.substring(index + 1);
      }
      break;
      case DTM.ATTRIBUTE_NODE :
      case DTM.ELEMENT_NODE : {
        Node node = getNode(nodeHandle);

        // assume not null.
        String qname = node.getNodeName();
        int index = qname.indexOf(':');

        prefix = (index < 0) ? "" : qname.substring(0, index);
      }
      break;
      default :
        prefix = "";
    }

    return prefix;
  }

  /**
   * Given a node handle, return its DOM-style namespace URI
   * (As defined in Namespaces, this is the declared URI which this node's
   * prefix -- or default in lieu thereof -- was mapped to.)
   *
   * <p>%REVIEW% Null or ""? -sb</p>
   *
   * @param nodeHandle the id of the node.
   * @return String URI value of this node's namespace, or null if no
   * namespace was resolved.
   */
  public String
  getNamespaceURI(int nodeHandle)
  {
//        if(JJK_NEWCODE)
//        {
    int id = makeNodeIdentity(nodeHandle);
    if (id == NULL) { return null; }
    Node node = m_nodes.get(id);
    return node.getNamespaceURI();
//        }
//        else
//        {
//            String nsuri;
//            short type = getNodeType(nodeHandle);
//
//            switch (type)
//            {
//                case DTM.ATTRIBUTE_NODE :
//                case DTM.ELEMENT_NODE :
//                case DTM.ENTITY_REFERENCE_NODE :
//                case DTM.NAMESPACE_NODE :
//                case DTM.PROCESSING_INSTRUCTION_NODE :
//                {
//                    Node node = getNode(nodeHandle);
//
//                    // assume not null.
//                    nsuri = node.getNamespaceURI();
//
//                    // %TBD% Handle DOM1?
//                }
//                break;
//                default :
//                    nsuri = null;
//            }
//
//            return nsuri;
//        }
  }

  /** Utility function: Given a DOM Text node, determine whether it is
   * logically followed by another Text or CDATASection node. This may
   * involve traversing into Entity References.
   *
   * %REVIEW% DOM Level 3 is expected to add functionality which may
   * allow us to retire this.
   */
  private Node
  logicalNextDOMTextNode(Node n)
  {
    Node p = n.getNextSibling();
    if (p == null) {
      // Walk out of any EntityReferenceNodes that ended with text
      for (n = n.getParentNode();
           n != null && ENTITY_REFERENCE_NODE == n.getNodeType();
           n = n.getParentNode()) {
        p = n.getNextSibling();
        if (p != null) {
          break;
        }
      }
    }
    n = p;
    while (n != null && ENTITY_REFERENCE_NODE == n.getNodeType()) {
      // Walk into any EntityReferenceNodes that start with text
      if (n.hasChildNodes()) {
        n = n.getFirstChild();
      } else {
        n = n.getNextSibling();
      }
    }
    if (n != null) {
      // Found a logical next sibling. Is it text?
      int ntype = n.getNodeType();
      if (TEXT_NODE != ntype && CDATA_SECTION_NODE != ntype) {
        n = null;
      }
    }
    return n;
  }

  /**
   * Given a node handle, return its node value. This is mostly
   * as defined by the DOM, but may ignore some conveniences.
   * <p>
   *
   * @param nodeHandle The node id.
   * @return String Value of this node, or null if not
   * meaningful for this node type.
   */
  public String
  getNodeValue(int nodeHandle)
  {
    // The _type(nodeHandle) call was taking the lion's share of our
    // time, and was wrong anyway since it wasn't converting handle to
    // identity. Inlined it.
    int type = _exptype(makeNodeIdentity(nodeHandle));
    type = (NULL != type) ? getNodeType(nodeHandle) : NULL;

    if (TEXT_NODE != type && CDATA_SECTION_NODE != type) {
      return getNode(nodeHandle).getNodeValue();
    }

    // If this is a DTM text node, it may be made of multiple DOM text
    // nodes -- including navigating into Entity References. DOM2DTM
    // records the first node in the sequence and requires that we
    // pick up the others when we retrieve the DTM node's value.
    //
    // %REVIEW% DOM Level 3 is expected to add a "whole text"
    // retrieval method which performs this function for us.
    Node node = getNode(nodeHandle);
    Node n = logicalNextDOMTextNode(node);
    if (n == null) {
      return node.getNodeValue();
    }

    FastStringBuffer buf = StringBufferPool.get();
    buf.append(node.getNodeValue());
    while (n != null) {
      buf.append(n.getNodeValue());
      n = logicalNextDOMTextNode(n);
    }
    String s = (buf.length() > 0) ? buf.toString() : "";
    StringBufferPool.free(buf);
    return s;
  }

  /**
   *   A document type declaration information item has the following properties:
   *
   *     1. [system identifier] The system identifier of the external subset, if
   *        it exists. Otherwise this property has no value.
   *
   * @return the system identifier String object, or null if there is none.
   */
  public String
  getDocumentTypeDeclarationSystemIdentifier()
  {

    Document doc;

    if (m_root.getNodeType() == Node.DOCUMENT_NODE) {
      doc = (Document) m_root;
    } else {
      doc = m_root.getOwnerDocument();
    }

    if (null != doc) {
      DocumentType dtd = doc.getDoctype();

      if (null != dtd) {
        return dtd.getSystemId();
      }
    }

    return null;
  }

  /**
   * Return the public identifier of the external subset,
   * normalized as described in 4.2.2 External Entities [XML]. If there is
   * no external subset or if it has no public identifier, this property
   * has no value.
   *
   * @return the public identifier String object, or null if there is none.
   */
  public String
  getDocumentTypeDeclarationPublicIdentifier()
  {

    Document doc;

    if (m_root.getNodeType() == Node.DOCUMENT_NODE) {
      doc = (Document) m_root;
    } else {
      doc = m_root.getOwnerDocument();
    }

    if (null != doc) {
      DocumentType dtd = doc.getDoctype();

      if (null != dtd) {
        return dtd.getPublicId();
      }
    }

    return null;
  }

  /**
   * Returns the <code>Element</code> whose <code>ID</code> is given by
   * <code>elementId</code>. If no such element exists, returns
   * <code>DTM.NULL</code>. Behavior is not defined if more than one element
   * has this <code>ID</code>. Attributes (including those
   * with the name "ID") are not of type ID unless so defined by DTD/Schema
   * information available to the DTM implementation.
   * Implementations that do not know whether attributes are of type ID or
   * not are expected to return <code>DTM.NULL</code>.
   *
   * <p>%REVIEW% Presumably IDs are still scoped to a single document,
   * and this operation searches only within a single document, right?
   * Wouldn't want collisions between DTMs in the same process.</p>
   *
   * @param elementId The unique <code>id</code> value for an element.
   * @return The handle of the matching element.
   */
  public int
  getElementById(String elementId)
  {

    Document doc = (m_root.getNodeType() == Node.DOCUMENT_NODE)
                   ? (Document) m_root : m_root.getOwnerDocument();

    if (null != doc) {
      Node elem = doc.getElementById(elementId);
      if (null != elem) {
        int elemHandle = getHandleFromNode(elem);

        if (DTM.NULL == elemHandle) {
          int identity = m_nodes.size() - 1;
          while (DTM.NULL != (identity = getNextNodeIdentity(identity))) {
            Node node = getNode(identity);
            if (node == elem) {
              elemHandle = getHandleFromNode(elem);
              break;
            }
          }
        }

        return elemHandle;
      }

    }
    return DTM.NULL;
  }

  /**
   * The getUnparsedEntityURI function returns the URI of the unparsed
   * entity with the specified name in the same document as the context
   * node (see [3.3 Unparsed Entities]). It returns the empty string if
   * there is no such entity.
   * <p>
   * XML processors may choose to use the System Identifier (if one
   * is provided) to resolve the entity, rather than the URI in the
   * Public Identifier. The details are dependent on the processor, and
   * we would have to support some form of plug-in resolver to handle
   * this properly. Currently, we simply return the System Identifier if
   * present, and hope that it a usable URI or that our caller can
   * map it to one.
   * TODO: Resolve Public Identifiers... or consider changing function name.
   * <p>
   * If we find a relative URI
   * reference, XML expects it to be resolved in terms of the base URI
   * of the document. The DOM doesn't do that for us, and it isn't
   * entirely clear whether that should be done here; currently that's
   * pushed up to a higher level of our application. (Note that DOM Level
   * 1 didn't store the document's base URI.)
   * TODO: Consider resolving Relative URIs.
   * <p>
   * (The DOM's statement that "An XML processor may choose to
   * completely expand entities before the structure model is passed
   * to the DOM" refers only to parsed entities, not unparsed, and hence
   * doesn't affect this function.)
   *
   * @param name A string containing the Entity Name of the unparsed
   * entity.
   *
   * @return String containing the URI of the Unparsed Entity, or an
   * empty string if no such entity exists.
   */
  public String
  getUnparsedEntityURI(String name)
  {

    String url = "";
    Document doc = (m_root.getNodeType() == Node.DOCUMENT_NODE)
                   ? (Document) m_root : m_root.getOwnerDocument();

    if (null != doc) {
      DocumentType doctype = doc.getDoctype();

      if (null != doctype) {
        NamedNodeMap entities = doctype.getEntities();
        if (null == entities) {
          return url;
        }
        Entity entity = (Entity) entities.getNamedItem(name);
        if (null == entity) {
          return url;
        }

        String notationName = entity.getNotationName();

        if (null != notationName) { // then it's unparsed
          // The draft says: "The XSLT processor may use the public
          // identifier to generate a URI for the entity instead of the URI
          // specified in the system identifier. If the XSLT processor does
          // not use the public identifier to generate the URI, it must use
          // the system identifier; if the system identifier is a relative
          // URI, it must be resolved into an absolute URI using the URI of
          // the resource containing the entity declaration as the base
          // URI [RFC2396]."
          // So I'm falling a bit short here.
          url = entity.getSystemId();

          if (null == url) {
            url = entity.getPublicId();
          } else {
            // This should be resolved to an absolute URL, but that's hard
            // to do from here.
          }
        }
      }
    }

    return url;
  }

  /**
   *     5. [specified] A flag indicating whether this attribute was actually
   *        specified in the start-tag of its element, or was defaulted from the
   *        DTD.
   *
   * @param attributeHandle the attribute handle
   * @return <code>true</code> if the attribute was specified;
   *         <code>false</code> if it was defaulted.
   */
  public boolean
  isAttributeSpecified(int attributeHandle)
  {
    int type = getNodeType(attributeHandle);

    if (DTM.ATTRIBUTE_NODE == type) {
      Attr attr = (Attr)getNode(attributeHandle);
      return attr.getSpecified();
    }
    return false;
  }

  /** Bind an IncrementalSAXSource to this DTM. NOT RELEVANT for DOM2DTM, since
   * we're wrapped around an existing DOM.
   *
   * @param source The IncrementalSAXSource that we want to receive events from
   * on demand.
   */
  public void
  setIncrementalSAXSource(IncrementalSAXSource source)
  {
  }

  /** getContentHandler returns "our SAX builder" -- the thing that
   * someone else should send SAX events to in order to extend this
   * DTM model.
   *
   * @return null if this model doesn't respond to SAX events,
   * "this" if the DTM object has a built-in SAX ContentHandler,
   * the IncrementalSAXSource if we're bound to one and should receive
   * the SAX stream via it for incremental build purposes...
   * */
  public org.xml.sax.ContentHandler
  getContentHandler()
  {
    return null;
  }

  /**
   * Return this DTM's lexical handler.
   *
   * %REVIEW% Should this return null if construction already done/begun?
   *
   * @return null if this model doesn't respond to lexical SAX events,
   * "this" if the DTM object has a built-in SAX ContentHandler,
   * the IncrementalSAXSource if we're bound to one and should receive
   * the SAX stream via it for incremental build purposes...
   */
  public org.xml.sax.ext.LexicalHandler
  getLexicalHandler()
  {

    return null;
  }


  /**
   * Return this DTM's EntityResolver.
   *
   * @return null if this model doesn't respond to SAX entity ref events.
   */
  public org.xml.sax.EntityResolver
  getEntityResolver()
  {

    return null;
  }

  /**
   * Return this DTM's DTDHandler.
   *
   * @return null if this model doesn't respond to SAX dtd events.
   */
  public org.xml.sax.DTDHandler
  getDTDHandler()
  {

    return null;
  }

  /**
   * Return this DTM's ErrorHandler.
   *
   * @return null if this model doesn't respond to SAX error events.
   */
  public org.xml.sax.ErrorHandler
  getErrorHandler()
  {

    return null;
  }

  /**
   * Return this DTM's DeclHandler.
   *
   * @return null if this model doesn't respond to SAX Decl events.
   */
  public org.xml.sax.ext.DeclHandler
  getDeclHandler()
  {

    return null;
  }

  /** @return true iff we're building this model incrementally (eg
   * we're partnered with a IncrementalSAXSource) and thus require that the
   * transformation and the parse run simultaneously. Guidance to the
   * DTMManager.
   * */
  public boolean
  needsTwoThreads()
  {
    return false;
  }

  // ========== Direct SAX Dispatch, for optimization purposes ========

  /**
   * Returns whether the specified <var>ch</var> conforms to the XML 1.0 definition
   * of whitespace.  Refer to <A href="http://www.w3.org/TR/1998/REC-xml-19980210#NT-S">
   * the definition of <CODE>S</CODE></A> for details.
   * @param   ch      Character to check as XML whitespace.
   * @return          =true if <var>ch</var> is XML whitespace; otherwise =false.
   */
  private static boolean
  isSpace(char ch)
  {
    return XMLCharacterRecognizer.isWhiteSpace(ch);  // Take the easy way out for now.
  }

  /**
   * Directly call the
   * characters method on the passed ContentHandler for the
   * string-value of the given node (see http://www.w3.org/TR/xpath#data-model
   * for the definition of a node's string-value). Multiple calls to the
   * ContentHandler's characters methods may well occur for a single call to
   * this method.
   *
   * @param nodeHandle The node ID.
   * @param ch A non-null reference to a ContentHandler.
   *
   * @throws org.xml.sax.SAXException
   */
  public void
  dispatchCharactersEvents(
    int nodeHandle, org.xml.sax.ContentHandler ch,
    boolean normalize)
  throws org.xml.sax.SAXException
  {
    if (normalize) {
      XMLString str = getStringValue(nodeHandle);
      str = str.fixWhiteSpace(true, true, false);
      str.dispatchCharactersEvents(ch);
    } else {
      int type = getNodeType(nodeHandle);
      Node node = getNode(nodeHandle);
      dispatchNodeData(node, ch, 0);
      // Text coalition -- a DTM text node may represent multiple
      // DOM nodes.
      if (TEXT_NODE == type || CDATA_SECTION_NODE == type) {
        while (null != (node = logicalNextDOMTextNode(node))) {
          dispatchNodeData(node, ch, 0);
        }
      }
    }
  }

  /**
   * Retrieve the text content of a DOM subtree, appending it into a
   * user-supplied FastStringBuffer object. Note that attributes are
   * not considered part of the content of an element.
   * <p>
   * There are open questions regarding whitespace stripping.
   * Currently we make no special effort in that regard, since the standard
   * DOM doesn't yet provide DTD-based information to distinguish
   * whitespace-in-element-context from genuine #PCDATA. Note that we
   * should probably also consider xml:space if/when we address this.
   * DOM Level 3 may solve the problem for us.
   * <p>
   * %REVIEW% Note that as a DOM-level operation, it can be argued that this
   * routine _shouldn't_ perform any processing beyond what the DOM already
   * does, and that whitespace stripping and so on belong at the DTM level.
   * If you want a stripped DOM view, wrap DTM2DOM around DOM2DTM.
   *
   * @param node Node whose subtree is to be walked, gathering the
   * contents of all Text or CDATASection nodes.
   */
  @SuppressWarnings("fallthrough")
  protected static void
  dispatchNodeData(Node node,
                   org.xml.sax.ContentHandler ch,
                   int depth)
  throws org.xml.sax.SAXException
  {

    switch (node.getNodeType()) {
      case Node.DOCUMENT_FRAGMENT_NODE :
      case Node.DOCUMENT_NODE :
      case Node.ELEMENT_NODE : {
        for (Node child = node.getFirstChild(); null != child;
             child = child.getNextSibling()) {
          dispatchNodeData(child, ch, depth + 1);
        }
      }
      break;
      case Node.PROCESSING_INSTRUCTION_NODE : // %REVIEW%
      case Node.COMMENT_NODE :
        if (0 != depth) {
          break;
        }
      // NOTE: Because this operation works in the DOM space, it does _not_ attempt
      // to perform Text Coalition. That should only be done in DTM space.
      case Node.TEXT_NODE :
      case Node.CDATA_SECTION_NODE :
      case Node.ATTRIBUTE_NODE :
        String str = node.getNodeValue();
        if (ch instanceof org.apache.xml.dtm.ref.dom2dtm.DOM2DTM.CharacterNodeHandler) {
          ((org.apache.xml.dtm.ref.dom2dtm.DOM2DTM.CharacterNodeHandler)ch).characters(node);
        } else {
          ch.characters(str.toCharArray(), 0, str.length());
        }
        break;
//    /* case Node.PROCESSING_INSTRUCTION_NODE :
//      // warning(XPATHErrorResources.WG_PARSING_AND_PREPARING);
//      break; */
      default :
        // ignore
        break;
    }
  }

  TreeWalker m_walker = new TreeWalker(null);

  /**
   * Directly create SAX parser events from a subtree.
   *
   * @param nodeHandle The node ID.
   * @param ch A non-null reference to a ContentHandler.
   *
   * @throws org.xml.sax.SAXException
   */
  public void
  dispatchToEvents(int nodeHandle, org.xml.sax.ContentHandler ch)
  throws org.xml.sax.SAXException
  {
    TreeWalker treeWalker = m_walker;
    ContentHandler prevCH = treeWalker.getContentHandler();

    if (null != prevCH) {
      treeWalker = new TreeWalker(null);
    }
    treeWalker.setContentHandler(ch);

    try {
      Node node = getNode(nodeHandle);
      treeWalker.traverseFragment(node);
    } finally {
      treeWalker.setContentHandler(null);
    }
  }

  /**
   * For the moment all the run time properties are ignored by this
   * class.
   *
   * @param property a <code>String</code> value
   * @param value an <code>Object</code> value
   */
  public void
  setProperty(String property, Object value)
  {
  }

  /**
   * No source information is available for DOM2DTM, so return
   * <code>null</code> here.
   *
   * @param node an <code>int</code> value
   * @return null
   */
  public SourceLocator
  getSourceLocatorFor(int node)
  {
    return null;
  }

}


