/*
 * 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 apache@apache.org.
 *
 * 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.dtm.ref;

import org.w3c.dom.*;
import org.apache.xml.dtm.*;
import org.apache.xml.dtm.Axis;

/**
 * <meta name="usage" content="internal"/>
 * <code>DTMNodeProxy</code> presents a DOM Node API front-end to the DTM model.
 * <p>
 * It does _not_ attempt to address the "node identity" question; no effort
 * is made to prevent the creation of multiple proxies referring to a single
 * DTM node. Users can create a mechanism for managing this, or relinquish the
 * use of "==" and use the .sameNodeAs() mechanism, which is under
 * consideration for future versions of the DOM.
 * <p>
 * DTMNodeProxy may be subclassed further to present specific DOM node types.
 *
 * @see org.w3c.dom
 */
public class DTMNodeProxy
  implements Node, Document, Text, Element, Attr,
                   ProcessingInstruction, Comment, DocumentFragment
{

  /** The DTM for this node. */
  public DTM dtm;

  /** The DTM node handle. */
  int node;
        
  /** The DOMImplementation object */
  static final DOMImplementation implementation=new DTMNodeProxyImplementation();

  /**
   * Create a DTMNodeProxy Node representing a specific Node in a DTM
   *
   * @param dtm The DTM Reference, must be non-null.
   * @param node The DTM node handle.
   */
  DTMNodeProxy(DTM dtm, int node)
  {
    this.dtm = dtm;
    this.node = node;
  }

  /**
   * NON-DOM: Return the DTM model
   *
   * @return The DTM that this proxy is a representative for.
   */
  public final DTM getDTM()
  {
    return dtm;
  }

  /**
   * NON-DOM: Return the DTM node number
   *
   * @return The DTM node handle.
   */
  public final int getDTMNodeNumber()
  {
    return node;
  }

  /**
   * Test for equality based on node number.
   *
   * @param node A DTM node proxy reference.
   *
   * @return true if the given node has the same handle as this node.
   */
  public final boolean equals(Node node)
  {

    try
    {
      DTMNodeProxy dtmp = (DTMNodeProxy) node;

      // return (dtmp.node == this.node);
      // Patch attributed to Gary L Peskin <garyp@firstech.com>
      return (dtmp.node == this.node) && (dtmp.dtm == this.dtm);
    }
    catch (ClassCastException cce)
    {
      return false;
    }
  }

  /**
   * Test for equality based on node number.
   *
   * @param node A DTM node proxy reference.
   *
   * @return true if the given node has the same handle as this node.
   */
  public final boolean equals(Object node)
  {

    try
    {

      // DTMNodeProxy dtmp = (DTMNodeProxy)node;
      // return (dtmp.node == this.node);
      // Patch attributed to Gary L Peskin <garyp@firstech.com>
      return equals((Node) node);
    }
    catch (ClassCastException cce)
    {
      return false;
    }
  }

  /**
   * FUTURE DOM: Test node identity, in lieu of Node==Node
   *
   * @param other
   *
   * @return true if the given node has the same handle as this node.
   */
  public final boolean sameNodeAs(Node other)
  {

    if (!(other instanceof DTMNodeProxy))
      return false;

    DTMNodeProxy that = (DTMNodeProxy) other;

    return this.dtm == that.dtm && this.node == that.node;
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final String getNodeName()
  {
    return dtm.getNodeName(node);
  }

  /**
   * A PI's "target" states what processor channel the PI's data
   * should be directed to. It is defined differently in HTML and XML.
   * <p>
   * In XML, a PI's "target" is the first (whitespace-delimited) token
   * following the "<?" token that begins the PI.
   * <p>
   * In HTML, target is always null.
   * <p>
   * Note that getNodeName is aliased to getTarget.
   *
   * @return
   */
  public final String getTarget()
  {
    return dtm.getNodeName(node);
  }  // getTarget():String

  /**
   *
   * @return
   * @see org.w3c.dom.Node as of DOM Level 2
   */
  public final String getLocalName()
  {
    return dtm.getLocalName(node);
  }

  /**
   * @return The prefix for this node.
   * @see org.w3c.dom.Node as of DOM Level 2
   */
  public final String getPrefix()
  {
    return dtm.getPrefix(node);
  }

  /**
   *
   * @param prefix
   *
   * @throws DOMException
   * @see org.w3c.dom.Node as of DOM Level 2 -- DTMNodeProxy is read-only
   */
  public final void setPrefix(String prefix) throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node as of DOM Level 2
   */
  public final String getNamespaceURI()
  {
    return dtm.getNamespaceURI(node);
  }

  /** Ask whether we support a given DOM feature.
   * In fact, we do not _fully_ support any DOM feature -- we're a
   * read-only subset -- so arguably we should always return false.
   * Or we could say that we support DOM Core Level 2 but all nodes
   * are read-only. Unclear which answer is least misleading.
   * 
   * NON-DOM method. This was present in early drafts of DOM Level 2,
   * but was renamed isSupported. It's present here only because it's
   * cheap, harmless, and might help some poor fool who is still trying
   * to use an early Working Draft of the DOM.
   *
   * @param feature
   * @param version
   *
   * @return false
   */
  public final boolean supports(String feature, String version)
  {
    return implementation.hasFeature(feature,version);
    //throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /** Ask whether we support a given DOM feature.
   * In fact, we do not _fully_ support any DOM feature -- we're a
   * read-only subset -- so arguably we should always return false.
   *
   * @param feature
   * @param version
   *
   * @return false
   * @see org.w3c.dom.Node as of DOM Level 2
   */
  public final boolean isSupported(String feature, String version)
  {
    return implementation.hasFeature(feature,version);
    // throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Node
   */
  public final String getNodeValue() throws DOMException
  {
    return dtm.getNodeValue(node);
  }

  /**
   *
   * @param nodeValue
   *
   * @throws DOMException
   * @see org.w3c.dom.Node -- DTMNodeProxy is read-only
   */
  public final void setNodeValue(String nodeValue) throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final short getNodeType()
  {
    return (short) dtm.getNodeType(node);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Node getParentNode()
  {

    if (getNodeType() == Node.ATTRIBUTE_NODE)
      return null;

    int newnode = dtm.getParent(node);

    return (newnode == DTM.NULL) ? null : dtm.getNode(newnode);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Node getOwnerNode()
  {

    int newnode = dtm.getParent(node);

    return (newnode == DTM.NULL) ? null : dtm.getNode(newnode);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final NodeList getChildNodes()
  {
                
    // Annoyingly, AxisIterators do not currently implement DTMIterator, so
    // we can't just wap DTMNodeList around an Axis.CHILD iterator.
    // Instead, we've created a special-case operating mode for that object.
    return new DTMNodeList(dtm,node);

    // throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Node getFirstChild()
  {

    int newnode = dtm.getFirstChild(node);

    return (newnode == DTM.NULL) ? null : dtm.getNode(newnode);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Node getLastChild()
  {

    int newnode = dtm.getLastChild(node);

    return (newnode == DTM.NULL) ? null : dtm.getNode(newnode);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Node getPreviousSibling()
  {

    int newnode = dtm.getPreviousSibling(node);

    return (newnode == DTM.NULL) ? null : dtm.getNode(newnode);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Node getNextSibling()
  {

    // Attr's Next is defined at DTM level, but not at DOM level.
    if (dtm.getNodeType(node) == Node.ATTRIBUTE_NODE)
      return null;

    int newnode = dtm.getNextSibling(node);

    return (newnode == DTM.NULL) ? null : dtm.getNode(newnode);
  }

  // DTMNamedNodeMap m_attrs;

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final NamedNodeMap getAttributes()
  {

    return new DTMNamedNodeMap(dtm, node);
  }

  /**
   * Method hasAttribute
   *
   *
   * @param name
   *
   * (hasAttribute) @return
   */
  public boolean hasAttribute(String name)
  {
    return DTM.NULL != dtm.getAttributeNode(node,null,name);
  }

  /**
   * Method hasAttributeNS
   *
   *
   * @param name
   * @param x
   *
   * (hasAttributeNS) @return
   */
  public boolean hasAttributeNS(String name, String x)
  {
    return DTM.NULL != dtm.getAttributeNode(node,x,name);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final Document getOwnerDocument()
  {
  	// Note that this uses the DOM-compatable version of the call
	return (Document)(dtm.getNode(dtm.getOwnerDocument(node)));
  }

  /**
   *
   * @param newChild
   * @param refChild
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Node -- DTMNodeProxy is read-only
   */
  public final Node insertBefore(Node newChild, Node refChild)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @param newChild
   * @param oldChild
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Node -- DTMNodeProxy is read-only
   */
  public final Node replaceChild(Node newChild, Node oldChild)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @param oldChild
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Node -- DTMNodeProxy is read-only
   */
  public final Node removeChild(Node oldChild) throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @param newChild
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Node -- DTMNodeProxy is read-only
   */
  public final Node appendChild(Node newChild) throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Node
   */
  public final boolean hasChildNodes()
  {
    return (DTM.NULL != dtm.getFirstChild(node));
  }

  /**
   *
   * @param deep
   *
   * @return
   * @see org.w3c.dom.Node -- DTMNodeProxy is read-only
   */
  public final Node cloneNode(boolean deep)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Document
   */
  public final DocumentType getDoctype()
  {
    return null;
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Document
   */
  public final DOMImplementation getImplementation()
  {
    return implementation;
  }

  /** This is a bit of a problem in DTM, since a DTM may be a Document
   * Fragment and hence not have a clear-cut Document Element. We can
   * make it work in the well-formed cases but would that be confusing for others?
   * 
   * @return
   * @see org.w3c.dom.Document
   */
  public final Element getDocumentElement()
  {
		int dochandle=dtm.getDocument();
		int elementhandle=dtm.NULL;
		for(int kidhandle=dtm.getFirstChild(dochandle);
				kidhandle!=dtm.NULL;
				kidhandle=dtm.getNextSibling(kidhandle))
		{
			switch(dtm.getNodeType(kidhandle))
			{
			case Node.ELEMENT_NODE:
				if(elementhandle!=dtm.NULL) 
				{
					elementhandle=dtm.NULL; // More than one; ill-formed.
					kidhandle=dtm.getLastChild(dochandle); // End loop
				}
				else
					elementhandle=kidhandle;
				break;
				
			// These are harmless; document is still wellformed
			case Node.COMMENT_NODE:
			case Node.PROCESSING_INSTRUCTION_NODE:
			case Node.DOCUMENT_TYPE_NODE:
				break;
					
			default:
				elementhandle=dtm.NULL; // ill-formed
				kidhandle=dtm.getLastChild(dochandle); // End loop
				break;
			}
		}
		if(elementhandle==dtm.NULL)
			throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
		else
			return (Element)(dtm.getNode(elementhandle));
  }

  /**
   *
   * @param tagName
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document
   */
  public final Element createElement(String tagName) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Document
   */
  public final DocumentFragment createDocumentFragment()
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param data
   *
   * @return
   * @see org.w3c.dom.Document
   */
  public final Text createTextNode(String data)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param data
   *
   * @return
   * @see org.w3c.dom.Document
   */
  public final Comment createComment(String data)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param data
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document
   */
  public final CDATASection createCDATASection(String data)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param target
   * @param data
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document
   */
  public final ProcessingInstruction createProcessingInstruction(
                                                                 String target, String data) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param name
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document
   */
  public final Attr createAttribute(String name) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param name
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document
   */
  public final EntityReference createEntityReference(String name)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param tagname
   *
   * @return
   * @see org.w3c.dom.Document
   */
  public final NodeList getElementsByTagName(String tagname)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param importedNode
   * @param deep
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document as of DOM Level 2 -- DTMNodeProxy is read-only
   */
  public final Node importNode(Node importedNode, boolean deep)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
  }

  /**
   *
   * @param namespaceURI
   * @param qualifiedName
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document as of DOM Level 2
   */
  public final Element createElementNS(
                                       String namespaceURI, String qualifiedName) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param namespaceURI
   * @param qualifiedName
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Document as of DOM Level 2
   */
  public final Attr createAttributeNS(
                                      String namespaceURI, String qualifiedName) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param namespaceURI
   * @param localName
   *
   * @return
   * @see org.w3c.dom.Document as of DOM Level 2
   */
  public final NodeList getElementsByTagNameNS(String namespaceURI,
                                               String localName)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param elementId
   *
   * @return
   * @see org.w3c.dom.Document as of DOM Level 2
   */
  public final Element getElementById(String elementId)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param offset
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Text
   */
  public final Text splitText(int offset) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final String getData() throws DOMException
  {
    return dtm.getNodeValue(node);
  }

  /**
   *
   * @param data
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final void setData(String data) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.CharacterData
   */
  public final int getLength()
  {
    // %OPT% This should do something smarter?
    return dtm.getNodeValue(node).length();
  }

  /**
   *
   * @param offset
   * @param count
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final String substringData(int offset, int count) throws DOMException
  {
    return getData().substring(offset,offset+count);
  }

  /**
   *
   * @param arg
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final void appendData(String arg) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param offset
   * @param arg
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final void insertData(int offset, String arg) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param offset
   * @param count
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final void deleteData(int offset, int count) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param offset
   * @param count
   * @param arg
   *
   * @throws DOMException
   * @see org.w3c.dom.CharacterData
   */
  public final void replaceData(int offset, int count, String arg)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Element
   */
  public final String getTagName()
  {
    return dtm.getNodeName(node);
  }

  /**
   *
   * @param name
   *
   * @return
   * @see org.w3c.dom.Element
   */
  public final String getAttribute(String name)
  {

    DTMNamedNodeMap  map = new DTMNamedNodeMap(dtm, node);
    Node node = map.getNamedItem(name);
    return (null == node) ? null : node.getNodeValue();
  }

  /**
   *
   * @param name
   * @param value
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final void setAttribute(String name, String value)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param name
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final void removeAttribute(String name) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param name
   *
   * @return
   * @see org.w3c.dom.Element
   */
  public final Attr getAttributeNode(String name)
  {

    DTMNamedNodeMap  map = new DTMNamedNodeMap(dtm, node);
    return (Attr)map.getNamedItem(name);
  }

  /**
   *
   * @param newAttr
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final Attr setAttributeNode(Attr newAttr) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param oldAttr
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final Attr removeAttributeNode(Attr oldAttr) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * Introduced in DOM Level 2.
   *
   * @return
   */
  public boolean hasAttributes()
  {
    return DTM.NULL != dtm.getFirstAttribute(node);
  }

  /** @see org.w3c.dom.Element */
  public final void normalize()
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param namespaceURI
   * @param localName
   *
   * @return
   * @see org.w3c.dom.Element
   */
  public final String getAttributeNS(String namespaceURI, String localName)
  {
    DTMNamedNodeMap  map = new DTMNamedNodeMap(dtm, node);
    Node node = map.getNamedItemNS(namespaceURI,localName);
    return (null == node) ? null : node.getNodeValue();
  }

  /**
   *
   * @param namespaceURI
   * @param qualifiedName
   * @param value
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final void setAttributeNS(
                                   String namespaceURI, String qualifiedName, String value)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param namespaceURI
   * @param localName
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final void removeAttributeNS(String namespaceURI, String localName)
    throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param namespaceURI
   * @param localName
   *
   * @return
   * @see org.w3c.dom.Element
   */
  public final Attr getAttributeNodeNS(String namespaceURI, String localName)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @param newAttr
   *
   * @return
   *
   * @throws DOMException
   * @see org.w3c.dom.Element
   */
  public final Attr setAttributeNodeNS(Attr newAttr) throws DOMException
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Attr
   */
  public final String getName()
  {
    return dtm.getNodeName(node);
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Attr
   */
  public final boolean getSpecified()
  {
    // We really don't know which attributes might have come from the
    // source document versus from the DTD. Treat them all as having
    // been provided by the user.
    // %REVIEW% if/when we become aware of DTDs/schemae.
    return true;
  }

  /**
   *
   * @return
   * @see org.w3c.dom.Attr
   */
  public final String getValue()
  {
    return dtm.getNodeValue(node);
  }

  /**
   *
   * @param value
   * @see org.w3c.dom.Attr
   */
  public final void setValue(String value)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * Get the owner element of an attribute.
   *
   * @return
   * @see org.w3c.dom.Attr as of DOM Level 2
   */
  public final Element getOwnerElement()
  {
    if (getNodeType() != Node.ATTRIBUTE_NODE)
      return null;
    // In XPath and DTM data models, unlike DOM, an Attr's parent is its
    // owner element.
    int newnode = dtm.getParent(node);
    return (newnode == DTM.NULL) ? null : (Element)(dtm.getNode(newnode));
  }

  /**
   * NEEDSDOC Method adoptNode 
   *
   *
   * NEEDSDOC @param source
   *
   * NEEDSDOC (adoptNode) @return
   *
   * @throws DOMException
   */
  public Node adoptNode(Node source) throws DOMException
  {

    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying, as part of the XML declaration, the encoding
   * of this document. This is <code>null</code> when unspecified.
   * @since DOM Level 3
   *
   * NEEDSDOC ($objectName$) @return
   */
  public String getEncoding()
  {

    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying, as part of the XML declaration, the encoding
   * of this document. This is <code>null</code> when unspecified.
   * @since DOM Level 3
   *
   * NEEDSDOC @param encoding
   */
  public void setEncoding(String encoding)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying, as part of the XML declaration, whether this
   * document is standalone.
   * @since DOM Level 3
   *
   * NEEDSDOC ($objectName$) @return
   */
  public boolean getStandalone()
  {

    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying, as part of the XML declaration, whether this
   * document is standalone.
   * @since DOM Level 3
   *
   * NEEDSDOC @param standalone
   */
  public void setStandalone(boolean standalone)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying whether errors checking is enforced or not.
   * When set to <code>false</code>, the implementation is free to not
   * test every possible error case normally defined on DOM operations,
   * and not raise any <code>DOMException</code>. In case of error, the
   * behavior is undefined. This attribute is <code>true</code> by
   * defaults.
   * @since DOM Level 3
   *
   * NEEDSDOC ($objectName$) @return
   */
  public boolean getStrictErrorChecking()
  {

    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying whether errors checking is enforced or not.
   * When set to <code>false</code>, the implementation is free to not
   * test every possible error case normally defined on DOM operations,
   * and not raise any <code>DOMException</code>. In case of error, the
   * behavior is undefined. This attribute is <code>true</code> by
   * defaults.
   * @since DOM Level 3
   *
   * NEEDSDOC @param strictErrorChecking
   */
  public void setStrictErrorChecking(boolean strictErrorChecking)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying, as part of the XML declaration, the version
   * number of this document. This is <code>null</code> when unspecified.
   * @since DOM Level 3
   *
   * NEEDSDOC ($objectName$) @return
   */
  public String getVersion()
  {

    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }

  /**
   * <p>EXPERIMENTAL! Based on the <a
   * href='http://www.w3.org/TR/2001/WD-DOM-Level-3-Core-20010605'>Document
   * Object Model (DOM) Level 3 Core Working Draft of 5 June 2001.</a>.
   * <p>
   * An attribute specifying, as part of the XML declaration, the version
   * number of this document. This is <code>null</code> when unspecified.
   * @since DOM Level 3
   *
   * NEEDSDOC @param version
   */
  public void setVersion(String version)
  {
    throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
  }
        
        
  /** Inner class to support getDOMImplementation.
   */
  static class DTMNodeProxyImplementation implements DOMImplementation
  {
    public DocumentType createDocumentType(String qualifiedName,String publicId, String systemId)
    {
      throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);
    }
    public Document createDocument(String namespaceURI,String qualfiedName,DocumentType doctype)                        
    {
      // Could create a DTM... but why, when it'd have to be permanantly empty?
      throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);        
    }
    /** Ask whether we support a given DOM feature.
     * 
     * In fact, we do not _fully_ support any DOM feature -- we're a
     * read-only subset -- so arguably we should always return false.
     * On the other hand, it may be more practically useful to return
     * true and simply treat the whole DOM as read-only, failing on the
     * methods we can't support. I'm not sure which would be more useful
     * to the caller.
     */
    public boolean hasFeature(String feature,String version)
    {
      if( ("CORE".equals(feature.toUpperCase()) || "XML".equals(feature.toUpperCase())) 
					&& 
          ("1.0".equals(version) || "2.0".equals(version))
          )
        return true;
      return false;
    }
  }
}