/*

   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 org.apache.batik.dom;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.WeakHashMap;

import org.apache.batik.dom.events.DocumentEventSupport;
import org.apache.batik.dom.events.EventSupport;
import org.apache.batik.dom.traversal.TraversalSupport;
import org.apache.batik.dom.util.DOMUtilities;
import org.apache.batik.dom.xbl.GenericXBLManager;
import org.apache.batik.dom.xbl.XBLManager;
import org.apache.batik.i18n.Localizable;
import org.apache.batik.i18n.LocalizableSupport;
import org.apache.batik.util.CleanerThread;
import org.apache.batik.util.DOMConstants;
import org.apache.batik.util.SoftDoublyIndexedTable;
import org.apache.batik.util.XMLConstants;

import org.apache.xml.utils.PrefixResolver;

import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XObject;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.DOMConfiguration;
import org.w3c.dom.DOMError;
import org.w3c.dom.DOMErrorHandler;
import org.w3c.dom.DOMException;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.DOMLocator;
import org.w3c.dom.DOMStringList;
import org.w3c.dom.Element;
import org.w3c.dom.events.DocumentEvent;
import org.w3c.dom.events.Event;
import org.w3c.dom.events.MutationNameEvent;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.traversal.DocumentTraversal;
import org.w3c.dom.traversal.NodeFilter;
import org.w3c.dom.traversal.NodeIterator;
import org.w3c.dom.traversal.TreeWalker;
import org.w3c.dom.UserDataHandler;
import org.w3c.dom.xpath.XPathEvaluator;
import org.w3c.dom.xpath.XPathException;
import org.w3c.dom.xpath.XPathExpression;
import org.w3c.dom.xpath.XPathNSResolver;
import org.w3c.dom.xpath.XPathResult;

/**
 * This class implements the {@link org.w3c.dom.Document} interface.
 *
 * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
 * @version $Id: AbstractDocument.java 1733416 2016-03-03 07:07:13Z gadams $
 */
public abstract class AbstractDocument
    extends    AbstractParentNode
    implements Document,
               DocumentEvent,
               DocumentTraversal,
               Localizable,
               XPathEvaluator {

    /**
     * The error messages bundle class name.
     */
    protected static final String RESOURCES =
        "org.apache.batik.dom.resources.Messages";

    /**
     * The localizable support for the error messages.
     */
    protected transient LocalizableSupport localizableSupport =
        new LocalizableSupport
        (RESOURCES, getClass().getClassLoader());

    /**
     * The DOM implementation.
     */
    protected transient DOMImplementation implementation;

    /**
     * The traversal support.
     */
    protected transient TraversalSupport traversalSupport;

    /**
     * The DocumentEventSupport.
     */
    protected transient DocumentEventSupport documentEventSupport;

    /**
     * Whether the event dispatching must be done.
     */
    protected transient boolean eventsEnabled;

    /**
     * The ElementsByTagName lists.
     */
    protected transient WeakHashMap elementsByTagNames;

    /**
     * The ElementsByTagNameNS lists.
     */
    protected transient WeakHashMap elementsByTagNamesNS;

    /**
     * Input encoding of this document.
     */
    protected String inputEncoding;

    /**
     * XML encoding of this document.
     */
    protected String xmlEncoding;

    /**
     * XML version of this document.
     */
    protected String xmlVersion = XMLConstants.XML_VERSION_10;

    /**
     * Whether this document is standalone.
     */
    protected boolean xmlStandalone;

    /**
     * The document URI.
     */
    protected String documentURI;

    /**
     * Whether strict error checking is in force.
     */
    protected boolean strictErrorChecking = true;

    /**
     * The DOMConfiguration object for this document.
     */
    protected DocumentConfiguration domConfig;

    /**
     * The XBL manager for this document.
     */
    protected transient XBLManager xblManager = new GenericXBLManager();

    /**
     * The elementsById lists.
     * This is keyed on 'id'.  the entry is either
     * a IdSoftReference to the element or a List of
     * IdSoftReferences (if there is more than one element
     * owned by this document with a particular 'id').
     */
    protected transient Map elementsById;

    /**
     * Creates a new document.
     */
    protected AbstractDocument() {
    }

    /**
     * Creates a new document.
     */
    public AbstractDocument(DocumentType dt, DOMImplementation impl) {
        implementation = impl;
        if (dt != null) {
            if (dt instanceof GenericDocumentType) {
                GenericDocumentType gdt = (GenericDocumentType)dt;
                if (gdt.getOwnerDocument() == null)
                    gdt.setOwnerDocument(this);
            }
            appendChild(dt);
        }
    }

    /**
     * Sets the input encoding that was used when the document was being
     * parsed.
     */
    public void setDocumentInputEncoding(String ie) {
        inputEncoding = ie;
    }

    /**
     * Sets the XML encoding that was found in the XML prolog.
     */
    public void setDocumentXmlEncoding(String xe) {
        xmlEncoding = xe;
    }

    /**
     * Implements {@link org.apache.batik.i18n.Localizable#setLocale(Locale)}.
     */
    public void setLocale(Locale l) {
        localizableSupport.setLocale(l);
    }

    /**
     * Implements {@link org.apache.batik.i18n.Localizable#getLocale()}.
     */
    public Locale getLocale() {
        return localizableSupport.getLocale();
    }

    /**
     * Implements {@link
     * org.apache.batik.i18n.Localizable#formatMessage(String,Object[])}.
     */
    public String formatMessage(String key, Object[] args)
        throws MissingResourceException {
        return localizableSupport.formatMessage(key, args);
    }

    /**
     * Tests whether the event dispatching must be done.
     */
    public boolean getEventsEnabled() {
        return eventsEnabled;
    }

    /**
     * Sets the eventsEnabled property.
     */
    public void setEventsEnabled(boolean b) {
        eventsEnabled = b;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Node#getNodeName()}.
     * @return "#document".
     */
    public String getNodeName() {
        return "#document";
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Node#getNodeType()}.
     * @return {@link org.w3c.dom.Node#DOCUMENT_NODE}
     */
    public short getNodeType() {
        return DOCUMENT_NODE;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getDoctype()}.
     */
    public DocumentType getDoctype() {
        for (Node n = getFirstChild(); n != null; n = n.getNextSibling()) {
            if (n.getNodeType() == DOCUMENT_TYPE_NODE) {
                return (DocumentType)n;
            }
        }
        return null;
    }

    /**
     * Sets the document type node.
     */
    public void setDoctype(DocumentType dt) {
        if (dt != null) {
            appendChild(dt);
            ((ExtendedNode)dt).setReadonly(true);
        }
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getImplementation()}.
     * @return {@link #implementation}
     */
    public DOMImplementation getImplementation() {
        return implementation;
    }

    /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.Document#getDocumentElement()}.
     */
    public Element getDocumentElement() {
        for (Node n = getFirstChild(); n != null; n = n.getNextSibling()) {
            if (n.getNodeType() == ELEMENT_NODE) {
                return (Element)n;
            }
        }
        return null;
    }

    /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.Document#importNode(Node,boolean)}.
     */
    public Node importNode(Node importedNode, boolean deep)
        throws DOMException {
        return importNode(importedNode, deep, false);
    }

    /**
     * Imports the given node into this document.
     * It does so deeply if <code>deep</code> is set to true.
     * It will not mark ID attributes as IDs if <code>trimId</code> is set to
     * true.  This is used primarily for the shadow trees of the 'use' elements
     * so they don't clutter the hash table.
     *
     * @param importedNode The node to import into this document.
     * @param deep Whether to perform a deep importation.
     * @param trimId Whether to make all cloned attributes not be ID attributes.
     */
    public Node importNode(Node importedNode, boolean deep, boolean trimId) {
        /*
         * The trimming of id's is used by the 'use' element to keep
         * down the amount of 'bogus' id's in the hashtable.
         */
        Node result;
        switch (importedNode.getNodeType()) {
        case ELEMENT_NODE:
            Element e = createElementNS(importedNode.getNamespaceURI(),
                                        importedNode.getNodeName());
            result = e;
            if (importedNode.hasAttributes()) {
                NamedNodeMap attr = importedNode.getAttributes();
                int len = attr.getLength();
                for (int i = 0; i < len; i++) {
                    Attr a = (Attr)attr.item(i);
                    if (!a.getSpecified()) continue;
                    AbstractAttr aa = (AbstractAttr)importNode(a, true);
                    if (trimId && aa.isId())
                        aa.setIsId(false); // don't consider this an Id.
                    e.setAttributeNodeNS(aa);
                }
            }
            break;

        case ATTRIBUTE_NODE:
            result = createAttributeNS(importedNode.getNamespaceURI(),
                                       importedNode.getNodeName());
            break;

        case TEXT_NODE:
            result = createTextNode(importedNode.getNodeValue());
            deep = false;
            break;

        case CDATA_SECTION_NODE:
            result = createCDATASection(importedNode.getNodeValue());
            deep = false;
            break;

        case ENTITY_REFERENCE_NODE:
            result = createEntityReference(importedNode.getNodeName());
            break;

        case PROCESSING_INSTRUCTION_NODE:
            result = createProcessingInstruction
                (importedNode.getNodeName(),
                 importedNode.getNodeValue());
            deep = false;
            break;

        case COMMENT_NODE:
            result = createComment(importedNode.getNodeValue());
            deep = false;
            break;

        case DOCUMENT_FRAGMENT_NODE:
            result = createDocumentFragment();
            break;

        case DOCUMENT_TYPE_NODE:
            DocumentType docType = (DocumentType) importedNode;
            GenericDocumentType copy = new GenericDocumentType(docType.getName(),
                    docType.getPublicId(), docType.getSystemId());
            copy.ownerDocument = this;
            result = copy;
            break;

        default:
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "import.node",
                                     new Object[] {});
        }

        if (importedNode instanceof AbstractNode) {
            // Only fire the UserDataHandler if the imported node is from
            // Batik's DOM implementation.
            fireUserDataHandlers(UserDataHandler.NODE_IMPORTED,
                                 importedNode,
                                 result);
        }

        if (deep) {
            for (Node n = importedNode.getFirstChild();
                 n != null;
                 n = n.getNextSibling()) {
                result.appendChild(importNode(n, true));
            }
        }
        return result;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Node#cloneNode(boolean)}.
     */
    public Node cloneNode(boolean deep) {
        Document n = (Document)newNode();
        copyInto(n);
        fireUserDataHandlers(UserDataHandler.NODE_CLONED, this, n);
        if (deep) {
            for (Node c = getFirstChild();
                 c != null;
                 c = c.getNextSibling()) {
                n.appendChild(n.importNode(c, deep));
            }
        }
        return n;
    }

    /**
     * Returns whether the given attribute node is an ID attribute.
     */
    public abstract boolean isId(Attr node);

    /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.Document#getElementById(String)}.
     */
    public Element getElementById(String id) {
        return getChildElementById(getDocumentElement(), id);
    }

    /**
     * Finds an element that is in the same document fragment as
     * 'requestor' that has 'id'.
     */
    public Element getChildElementById(Node requestor, String id) {
        if ((id == null) || (id.length()==0)) return null;
        if (elementsById == null) return null;

        Node root = getRoot(requestor);

        Object o = elementsById.get(id);
        if (o == null) return null;
        if (o instanceof IdSoftRef) {
            o = ((IdSoftRef)o).get();
            if (o == null) {
                elementsById.remove(id);
                return null;
            }
            Element e = (Element)o;
            if (getRoot(e) == root)
                return e;
            return null;
        }

        // Not a IdSoftRef so it must be a list.
        List l = (List)o;
        Iterator li = l.iterator();
        while (li.hasNext()) {
            IdSoftRef sr = (IdSoftRef)li.next();
            o = sr.get();
            if (o == null) {
                li.remove();
            } else {
                Element e = (Element)o;
                if (getRoot(e) == root)
                    return e;
            }
        }
        return null;
    }

    protected Node getRoot(Node n) {
        Node r = n;
        while (n != null) {
            r = n;
            n = n.getParentNode();
        }
        return r;
    }

    protected class IdSoftRef extends CleanerThread.SoftReferenceCleared {
        String id;
        List   list;
        IdSoftRef(Object o, String id) {
            super(o);
            this.id = id;
        }
        IdSoftRef(Object o, String id, List list) {
            super(o);
            this.id = id;
            this.list = list;
        }
        public void setList(List list) {
            this.list = list;
        }
        public void cleared() {
            if (elementsById == null) return;
            synchronized (elementsById) {
                if (list != null)
                    list.remove(this);
                else {
                  Object o = elementsById.remove(id);
                  if (o != this) // oops not us!
                      elementsById.put(id, o);
                }
            }
        }
    }

    /**
     * Remove the mapping for <code>element</code> to <code>id</code>
     */
    public void removeIdEntry(Element e, String id) {
        // Remove old Id mapping if we have one.
        if (id == null) return;
        if (elementsById == null) return;

        synchronized (elementsById) {
            Object o = elementsById.get(id);
            if (o == null) return;

            if (o instanceof IdSoftRef) {
                elementsById.remove(id);
                return;
            }

            List l = (List)o;
            Iterator li = l.iterator();
            while (li.hasNext()) {
                IdSoftRef ip = (IdSoftRef)li.next();
                o = ip.get();
                if (o == null) {
                    li.remove();
                } else if (e == o) {
                    li.remove();
                    break;
                }
            }

            if (l.size() == 0)
                elementsById.remove(id);
        }
    }

    public void addIdEntry(Element e, String id) {
        if (id == null) return;

        if (elementsById == null) {
            Map tmp = new HashMap();
            tmp.put(id, new IdSoftRef(e, id));
            elementsById = tmp;
            return;
        }

        synchronized (elementsById) {
            // Add new Id mapping.
            Object o = elementsById.get(id);
            if (o == null) {
                elementsById.put(id, new IdSoftRef(e, id));
                return;
            }
            if (o instanceof IdSoftRef) {
                IdSoftRef ip = (IdSoftRef)o;
                Object r = ip.get();
                if (r == null) { // reference is gone so replace it.
                    elementsById.put(id, new IdSoftRef(e, id));
                    return;
                }

                // Create new List for this id.
                List l = new ArrayList(4);
                ip.setList(l);
                l.add(ip);
                l.add(new IdSoftRef(e, id, l));
                elementsById.put(id, l);
                return;
            }

            List l = (List)o;
            l.add(new IdSoftRef(e, id, l));
        }
    }

    public void updateIdEntry(Element e, String oldId, String newId) {
        if ((oldId == newId) ||
            ((oldId != null) && (oldId.equals(newId))))
            return;

        removeIdEntry(e, oldId);

        addIdEntry(e, newId);
    }


    /**
     * Returns an ElementsByTagName object from the cache, if any.
     */
    public ElementsByTagName getElementsByTagName(Node n, String ln) {
        if (elementsByTagNames == null) {
            return null;
        }
        SoftDoublyIndexedTable t;
        t = (SoftDoublyIndexedTable)elementsByTagNames.get(n);
        if (t == null) {
            return null;
        }
        return (ElementsByTagName)t.get(null, ln);
    }

    /**
     * Puts an ElementsByTagName object in the cache.
     */
    public void putElementsByTagName(Node n, String ln, ElementsByTagName l) {
        if (elementsByTagNames == null) {
            elementsByTagNames = new WeakHashMap(11);
        }
        SoftDoublyIndexedTable t;
        t = (SoftDoublyIndexedTable)elementsByTagNames.get(n);
        if (t == null) {
            elementsByTagNames.put(n, t = new SoftDoublyIndexedTable());
        }
        t.put(null, ln, l);
    }

    /**
     * Returns an ElementsByTagNameNS object from the cache, if any.
     */
    public ElementsByTagNameNS getElementsByTagNameNS(Node n,
                                                      String ns,
                                                      String ln) {
        if (elementsByTagNamesNS == null) {
            return null;
        }
        SoftDoublyIndexedTable t;
        t = (SoftDoublyIndexedTable)elementsByTagNamesNS.get(n);
        if (t == null) {
            return null;
        }
        return (ElementsByTagNameNS)t.get(ns, ln);
    }

    /**
     * Puts an ElementsByTagNameNS object in the cache.
     */
    public void putElementsByTagNameNS(Node n, String ns, String ln,
                                       ElementsByTagNameNS l) {
        if (elementsByTagNamesNS == null) {
            elementsByTagNamesNS = new WeakHashMap(11);
        }
        SoftDoublyIndexedTable t;
        t = (SoftDoublyIndexedTable)elementsByTagNamesNS.get(n);
        if (t == null) {
            elementsByTagNamesNS.put(n, t = new SoftDoublyIndexedTable());
        }
        t.put(ns, ln, l);
    }

    // DocumentEvent /////////////////////////////////////////////////////////

    /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.events.DocumentEvent#createEvent(String)}.
     */
    public Event createEvent(String eventType) throws DOMException {
        if (documentEventSupport == null) {
            documentEventSupport =
                ((AbstractDOMImplementation)implementation).
                    createDocumentEventSupport();
        }
        return documentEventSupport.createEvent(eventType);
    }

    /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.events.DocumentEvent#canDispatch(String,String)}.
     */
    public boolean canDispatch(String ns, String eventType) {
        if (eventType == null) {
            return false;
        }
        if (ns != null && ns.length() == 0) {
            ns = null;
        }
        if (ns == null || ns.equals(XMLConstants.XML_EVENTS_NAMESPACE_URI)) {
            return eventType.equals("Event")
                || eventType.equals("MutationEvent")
                || eventType.equals("MutationNameEvent")
                || eventType.equals("UIEvent")
                || eventType.equals("MouseEvent")
                || eventType.equals("KeyEvent")
                || eventType.equals("KeyboardEvent")
                || eventType.equals("TextEvent")
                || eventType.equals("CustomEvent");
        }
        return false;
    }

    // DocumentTraversal /////////////////////////////////////////////////////

    /**
     * <b>DOM</b>: Implements {@link
     * DocumentTraversal#createNodeIterator(Node,int,NodeFilter,boolean)}.
     */
    public NodeIterator createNodeIterator(Node root,
                                           int whatToShow,
                                           NodeFilter filter,
                                           boolean entityReferenceExpansion)
        throws DOMException {
        if (traversalSupport == null) {
            traversalSupport = new TraversalSupport();
        }
        return traversalSupport.createNodeIterator(this, root, whatToShow,
                                                   filter,
                                                   entityReferenceExpansion);
    }

    /**
     * <b>DOM</b>: Implements {@link
     * DocumentTraversal#createTreeWalker(Node,int,NodeFilter,boolean)}.
     */
    public TreeWalker createTreeWalker(Node root,
                                       int whatToShow,
                                       NodeFilter filter,
                                       boolean entityReferenceExpansion)
        throws DOMException {
        return TraversalSupport.createTreeWalker(this, root, whatToShow,
                                                 filter,
                                                 entityReferenceExpansion);
    }

    /**
     * Detaches the given node iterator from this document.
     */
    public void detachNodeIterator(NodeIterator it) {
        traversalSupport.detachNodeIterator(it);
    }

    /**
     * Notifies this document that a node will be removed.
     */
    public void nodeToBeRemoved(Node node) {
        if (traversalSupport != null) {
            traversalSupport.nodeToBeRemoved(node);
        }
    }

    /**
     * Returns the current document.
     */
    protected AbstractDocument getCurrentDocument() {
        return this;
    }

    /**
     * Exports this node to the given document.
     * @param n The clone node.
     * @param d The destination document.
     */
    protected Node export(Node n, Document d) {
        throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                 "import.document",
                                 new Object[] {});
    }

    /**
     * Deeply exports this node to the given document.
     * @param n The clone node.
     * @param d The destination document.
     */
    protected Node deepExport(Node n, Document d) {
        throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                 "import.document",
                                 new Object[] {});
    }

    /**
     * Copy the fields of the current node into the given node.
     * @param n a node of the type of this.
     */
    protected Node copyInto(Node n) {
        super.copyInto(n);
        AbstractDocument ad = (AbstractDocument)n;
        ad.implementation = implementation;
        ad.localizableSupport = new LocalizableSupport
            (RESOURCES, getClass().getClassLoader());
        ad.inputEncoding = inputEncoding;
        ad.xmlEncoding = xmlEncoding;
        ad.xmlVersion = xmlVersion;
        ad.xmlStandalone = xmlStandalone;
        ad.documentURI = documentURI;
        ad.strictErrorChecking = strictErrorChecking;
        // XXX clone DocumentConfiguration?
        return n;
    }

    /**
     * Deeply copy the fields of the current node into the given node.
     * @param n a node of the type of this.
     */
    protected Node deepCopyInto(Node n) {
        super.deepCopyInto(n);
        AbstractDocument ad = (AbstractDocument)n;
        ad.implementation = implementation;
        ad.localizableSupport = new LocalizableSupport
            (RESOURCES, getClass().getClassLoader());
        return n;
    }

    /**
     * Checks the validity of a node to be inserted.
     */
    protected void checkChildType(Node n, boolean replace) {
        short t = n.getNodeType();
        switch (t) {
        case ELEMENT_NODE:
        case PROCESSING_INSTRUCTION_NODE:
        case COMMENT_NODE:
        case DOCUMENT_TYPE_NODE:
        case DOCUMENT_FRAGMENT_NODE:
            break;
        default:
            throw createDOMException(DOMException.HIERARCHY_REQUEST_ERR,
                                     "child.type",
                                     new Object[] { new Integer(getNodeType()),
                                                    getNodeName(),
                                                    new Integer(t),
                                                    n.getNodeName() });
        }
        if (!replace &&
            (t == ELEMENT_NODE && getDocumentElement() != null) ||
            (t == DOCUMENT_TYPE_NODE && getDoctype() != null)) {
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "document.child.already.exists",
                                     new Object[] { new Integer(t),
                                                    n.getNodeName() });
        }
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getInputEncoding()}.
     */
    public String getInputEncoding() {
        return inputEncoding;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getXmlEncoding()}.
     */
    public String getXmlEncoding() {
        return xmlEncoding;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getXmlStandalone()}.
     */
    public boolean getXmlStandalone() {
        return xmlStandalone;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#setXmlStandalone(boolean)}.
     */
    public void setXmlStandalone(boolean b) throws DOMException {
        xmlStandalone = b;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getXmlVersion()}.
     */
    public String getXmlVersion() {
        return xmlVersion;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#setXmlVersion(String)}.
     */
    public void setXmlVersion(String v) throws DOMException {
        if (v == null
                || !v.equals(XMLConstants.XML_VERSION_10)
                    && !v.equals(XMLConstants.XML_VERSION_11)) {
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "xml.version",
                                     new Object[] { v });
        }
        xmlVersion = v;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getStrictErrorChecking()}.
     */
    public boolean getStrictErrorChecking() {
        return strictErrorChecking;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#setStrictErrorChecking(boolean)}.
     */
    public void setStrictErrorChecking(boolean b) {
        strictErrorChecking = b;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getDocumentURI()}.
     */
    public String getDocumentURI() {
        return documentURI;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#setDocumentURI(String)}.
     */
    public void setDocumentURI(String uri) {
        documentURI = uri;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#getDomConfig()}.
     */
    public DOMConfiguration getDomConfig() {
        if (domConfig == null) {
            domConfig = new DocumentConfiguration();
        }
        return domConfig;
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#adoptNode(Node)}.
     */
    public Node adoptNode(Node n) throws DOMException {
        if (!(n instanceof AbstractNode)) {
            return null;
        }
        switch (n.getNodeType()) {
            case Node.DOCUMENT_NODE:
                throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                         "adopt.document",
                                         new Object[] {});
            case Node.DOCUMENT_TYPE_NODE:
                throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                         "adopt.document.type",
                                          new Object[] {});
            case Node.ENTITY_NODE:
            case Node.NOTATION_NODE:
                return null;
        }
        AbstractNode an = (AbstractNode) n;
        if (an.isReadonly()) {
            throw createDOMException
                (DOMException.NO_MODIFICATION_ALLOWED_ERR,
                 "readonly.node",
                 new Object[] { new Integer(an.getNodeType()),
                               an.getNodeName() });
        }
        Node parent = n.getParentNode();
        if (parent != null) {
            parent.removeChild(n);
        }
        adoptNode1((AbstractNode) n);
        return n;
    }

    /**
     * Helper function for {@link #adoptNode(Node)}.
     */
    protected void adoptNode1(AbstractNode n) {
        n.ownerDocument = this;
        switch (n.getNodeType()) {
            case Node.ATTRIBUTE_NODE:
                AbstractAttr attr = (AbstractAttr) n;
                attr.ownerElement = null;
                attr.unspecified = false;
                break;
            case Node.ELEMENT_NODE:
                NamedNodeMap nnm = n.getAttributes();
                int len = nnm.getLength();
                for (int i = 0; i < len; i++) {
                    attr = (AbstractAttr) nnm.item(i);
                    if (attr.getSpecified()) {
                        adoptNode1(attr);
                    }
                }
                break;
            case Node.ENTITY_REFERENCE_NODE:
                while (n.getFirstChild() != null) {
                    n.removeChild(n.getFirstChild());
                }
                break;
        }

        fireUserDataHandlers(UserDataHandler.NODE_ADOPTED, n, null);

        for (Node m = n.getFirstChild(); m != null; m = m.getNextSibling()) {
            switch (m.getNodeType()) {
                case Node.DOCUMENT_TYPE_NODE:
                case Node.ENTITY_NODE:
                case Node.NOTATION_NODE:
                    return;
            }
            adoptNode1((AbstractNode) m);
        }
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#renameNode(Node,String,String)}.
     */
    public Node renameNode(Node n, String ns, String qn) {
        AbstractNode an = (AbstractNode) n;
        if (an == getDocumentElement()) {
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "rename.document.element",
                                     new Object[] {});
        }
        int nt = n.getNodeType();
        if (nt != Node.ELEMENT_NODE && nt != Node.ATTRIBUTE_NODE) {
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "rename.node",
                                     new Object[] { new Integer(nt),
                                                    n.getNodeName() });
        }
        if (xmlVersion.equals(XMLConstants.XML_VERSION_11)
                && !DOMUtilities.isValidName11(qn)
                || !DOMUtilities.isValidName(qn)) {
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "wf.invalid.name",
                                     new Object[] { qn });
        }
        if (n.getOwnerDocument() != this) {
            throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                     "node.from.wrong.document",
                                     new Object[] { new Integer(nt),
                                                    n.getNodeName() });
        }
        int i = qn.indexOf(':');
        if (i == 0 || i == qn.length() - 1) {
            throw createDOMException(DOMException.NAMESPACE_ERR,
                                     "qname",
                                     new Object[] { new Integer(nt),
                                                    n.getNodeName(),
                                                    qn });
        }
        String prefix = DOMUtilities.getPrefix(qn);
        if (ns != null && ns.length() == 0) {
            ns = null;
        }
        if (prefix != null && ns == null) {
            throw createDOMException(DOMException.NAMESPACE_ERR,
                                     "prefix",
                                     new Object[] { new Integer(nt),
                                                    n.getNodeName(),
                                                    prefix });
        }
        if (strictErrorChecking) {
            if (XMLConstants.XML_PREFIX.equals(prefix)
                    && !XMLConstants.XML_NAMESPACE_URI.equals(ns)
                    || XMLConstants.XMLNS_PREFIX.equals(prefix)
                        && !XMLConstants.XMLNS_NAMESPACE_URI.equals(ns)) {
                throw createDOMException(DOMException.NAMESPACE_ERR,
                                         "namespace",
                                         new Object[] { new Integer(nt),
                                                        n.getNodeName(),
                                                        ns });
            }
        }

        String prevNamespaceURI = n.getNamespaceURI();
        String prevNodeName = n.getNodeName();
        if (nt == Node.ELEMENT_NODE) {
            Node parent = n.getParentNode();
            AbstractElement e = (AbstractElement) createElementNS(ns, qn);

            // Move event handlers across
            EventSupport es1 = an.getEventSupport();
            if (es1 != null) {
                EventSupport es2 = e.getEventSupport();
                if (es2 == null) {
                    AbstractDOMImplementation di
                        = (AbstractDOMImplementation) implementation;
                    es2 = di.createEventSupport(e);
                    setEventsEnabled(true);
                    e.eventSupport = es2;
                }
                es1.moveEventListeners(e.getEventSupport());
            }

            // Move user data across
            e.userData = e.userData == null
                ? null
                : (HashMap) an.userData.clone();
            e.userDataHandlers = e.userDataHandlers == null
                ? null
                : (HashMap) an.userDataHandlers.clone();

            // Remove from parent
            Node next = null;
            if (parent != null) {
                n.getNextSibling();
                parent.removeChild(n);
            }

            // Move child nodes across
            while (n.getFirstChild() != null) {
                e.appendChild(n.getFirstChild());
            }

            // Move attributes across
            NamedNodeMap nnm = n.getAttributes();
            for (int j = 0; j < nnm.getLength(); j++) {
                Attr a = (Attr) nnm.item(j);
                e.setAttributeNodeNS(a);
            }
            // while (nnm.getLength() > 0) {
            //     Attr a = (Attr) nnm.item(0);
            //     e.setAttributeNodeNS(a);
            // }

            // Reinsert into parent
            if (parent != null) {
                if (next == null) {
                    parent.appendChild(e);
                } else {
                    parent.insertBefore(next, e);
                }
            }

            fireUserDataHandlers(UserDataHandler.NODE_RENAMED, n, e);
            if (getEventsEnabled()) {
                MutationNameEvent ev =
                    (MutationNameEvent) createEvent("MutationNameEvent");
                ev.initMutationNameEventNS(XMLConstants.XML_EVENTS_NAMESPACE_URI,
                                           "DOMElementNameChanged",
                                           true,   // canBubbleArg
                                           false,  // cancelableArg
                                           null,   // relatedNodeArg
                                           prevNamespaceURI,
                                           prevNodeName);
                dispatchEvent(ev);
            }
            return e;
        } else {
            if (n instanceof AbstractAttrNS) {
                AbstractAttrNS a = (AbstractAttrNS) n;
                Element e = a.getOwnerElement();

                // Remove attribute from element
                if (e != null) {
                    e.removeAttributeNode(a);
                }

                // Update name
                a.namespaceURI = ns;
                a.nodeName = qn;

                // Reinsert attribute into element
                if (e != null) {
                    e.setAttributeNodeNS(a);
                }

                fireUserDataHandlers(UserDataHandler.NODE_RENAMED, a, null);
                if (getEventsEnabled()) {
                    MutationNameEvent ev =
                        (MutationNameEvent) createEvent("MutationNameEvent");
                    ev.initMutationNameEventNS(XMLConstants.XML_EVENTS_NAMESPACE_URI,
                                               "DOMAttrNameChanged",
                                               true,   // canBubbleArg
                                               false,  // cancelableArg
                                               a,      // relatedNodeArg
                                               prevNamespaceURI,
                                               prevNodeName);
                    dispatchEvent(ev);
                }
                return a;
            } else {
                AbstractAttr a = (AbstractAttr) n;
                Element e = a.getOwnerElement();

                // Remove attribute from element and create new one
                if (e != null) {
                    e.removeAttributeNode(a);
                }
                AbstractAttr a2 = (AbstractAttr) createAttributeNS(ns, qn);

                // Move attribute value across
                a2.setNodeValue(a.getNodeValue());

                // Move user data across
                a2.userData = a.userData == null
                    ? null
                    : (HashMap) a.userData.clone();
                a2.userDataHandlers = a.userDataHandlers == null
                    ? null
                    : (HashMap) a.userDataHandlers.clone();

                // Reinsert attribute into parent
                if (e != null) {
                    e.setAttributeNodeNS(a2);
                }

                fireUserDataHandlers(UserDataHandler.NODE_RENAMED, a, a2);
                if (getEventsEnabled()) {
                    MutationNameEvent ev
                        = (MutationNameEvent) createEvent("MutationNameEvent");
                    ev.initMutationNameEventNS(XMLConstants.XML_EVENTS_NAMESPACE_URI,
                                               "DOMAttrNameChanged",
                                               true,   // canBubbleArg
                                               false,  // cancelableArg
                                               a2,     // relatedNodeArg
                                               prevNamespaceURI,
                                               prevNodeName);
                    dispatchEvent(ev);
                }
                return a2;
            }
        }
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Document#normalizeDocument()}.
     * XXX Does not handle the 'entities' parameter yet.
     */
    public void normalizeDocument() {
        if (domConfig == null) {
            domConfig = new DocumentConfiguration();
        }
        boolean cdataSections = domConfig.getBooleanParameter
            (DOMConstants.DOM_CDATA_SECTIONS_PARAM);
        boolean comments = domConfig.getBooleanParameter
            (DOMConstants.DOM_COMMENTS_PARAM);
        boolean elementContentWhitespace = domConfig.getBooleanParameter
            (DOMConstants.DOM_ELEMENT_CONTENT_WHITESPACE_PARAM);
        boolean namespaceDeclarations = domConfig.getBooleanParameter
            (DOMConstants.DOM_NAMESPACE_DECLARATIONS_PARAM);
        boolean namespaces = domConfig.getBooleanParameter
            (DOMConstants.DOM_NAMESPACES_PARAM);
        boolean splitCdataSections = domConfig.getBooleanParameter
            (DOMConstants.DOM_SPLIT_CDATA_SECTIONS_PARAM);
        DOMErrorHandler errorHandler = (DOMErrorHandler) domConfig.getParameter
            (DOMConstants.DOM_ERROR_HANDLER_PARAM);
        normalizeDocument(getDocumentElement(),
                          cdataSections,
                          comments,
                          elementContentWhitespace,
                          namespaceDeclarations,
                          namespaces,
                          splitCdataSections,
                          errorHandler);
    }

    /**
     * Helper function for {@link #normalizeDocument()}.
     */
    protected boolean normalizeDocument(Element e,
                                        boolean cdataSections,
                                        boolean comments,
                                        boolean elementContentWhitepace,
                                        boolean namespaceDeclarations,
                                        boolean namespaces,
                                        boolean splitCdataSections,
                                        DOMErrorHandler errorHandler) {
        AbstractElement ae = (AbstractElement) e;
        Node n = e.getFirstChild();
        while (n != null) {
            int nt = n.getNodeType();
            if (nt == Node.TEXT_NODE
                    || !cdataSections && nt == Node.CDATA_SECTION_NODE) {
                // coalesce text nodes
                Node t = n;
                StringBuffer sb = new StringBuffer();
                sb.append(t.getNodeValue());
                n = n.getNextSibling();
                while (n != null && (n.getNodeType() == Node.TEXT_NODE
                            || !cdataSections && n.getNodeType() == Node.CDATA_SECTION_NODE) ) {
                    sb.append(n.getNodeValue());
                    Node next = n.getNextSibling();
                    e.removeChild(n);
                    n = next;
                }
                String s = sb.toString();
                if (s.length() == 0) {
                    Node next = n.getNextSibling();       // todo: Jlint says: n can be NULL
                    e.removeChild(n);
                    n = next;
                    continue;
                }
                if (!s.equals(t.getNodeValue())) {
                    if (!cdataSections && nt == Node.TEXT_NODE) {
                        n = createTextNode(s);
                        e.replaceChild(n, t);
                    } else {
                        n = t;
                        t.setNodeValue(s);
                    }
                } else {
                    n = t;
                }
                if (!elementContentWhitepace) {
                    // remove element content whitespace text nodes
                    nt = n.getNodeType();
                    if (nt == Node.TEXT_NODE) {
                        AbstractText tn = (AbstractText) n;
                        if (tn.isElementContentWhitespace()) {
                            Node next = n.getNextSibling();
                            e.removeChild(n);
                            n = next;
                            continue;
                        }
                    }
                }
                if (nt == Node.CDATA_SECTION_NODE && splitCdataSections) {
                    if (!splitCdata(e, n, errorHandler)) {
                        return false;
                    }
                }
            } else if (nt == Node.CDATA_SECTION_NODE && splitCdataSections) {
                // split CDATA sections
                if (!splitCdata(e, n, errorHandler)) {
                    return false;
                }
            } else if (nt == Node.COMMENT_NODE && !comments) {
                // remove comments
                Node next = n.getPreviousSibling();
                if (next == null) {
                    next = n.getNextSibling();
                }
                e.removeChild(n);
                n = next;
                continue;
            }

            n = n.getNextSibling();
        }

        NamedNodeMap nnm = e.getAttributes();
        LinkedList toRemove = new LinkedList();
        HashMap names = new HashMap();                    // todo names is not used ?
        for (int i = 0; i < nnm.getLength(); i++) {
            Attr a = (Attr) nnm.item(i);
            String prefix = a.getPrefix();                // todo : this breaks when a is null
            if (a != null && XMLConstants.XMLNS_PREFIX.equals(prefix)
                    || a.getNodeName().equals(XMLConstants.XMLNS_PREFIX)) {
                if (!namespaceDeclarations) {
                    // remove namespace declarations
                    toRemove.add(a);
                } else {
                    // namespace normalization
                    String ns = a.getNodeValue();
                    if (a.getNodeValue().equals(XMLConstants.XMLNS_NAMESPACE_URI)
                            || !ns.equals(XMLConstants.XMLNS_NAMESPACE_URI)) {
                        // XXX report error
                    } else {
                        names.put(prefix, ns);
                    }
                }
            }
        }

        if (!namespaceDeclarations) {
            // remove namespace declarations
            Iterator i = toRemove.iterator();
            while (i.hasNext()) {
                e.removeAttributeNode((Attr) i.next());
            }
        } else {
            if (namespaces) {
                // normalize element namespace
                String ens = e.getNamespaceURI();
                if (ens != null) {
                    String eprefix = e.getPrefix();
                    if (!compareStrings(ae.lookupNamespaceURI(eprefix), ens)) {
                        e.setAttributeNS
                            (XMLConstants.XMLNS_NAMESPACE_URI,
                             eprefix == null ? XMLConstants.XMLNS_PREFIX : "xmlns:" + eprefix,
                             ens);
                    }
                } else {
                    if (e.getLocalName() == null) {
                        // report error
                    } else {
                        if (ae.lookupNamespaceURI(null) == null) {
                            e.setAttributeNS
                                (XMLConstants.XMLNS_NAMESPACE_URI,
                                 XMLConstants.XMLNS_PREFIX,
                                 "");
                        }
                    }
                }
                // normalize attribute namespaces
                nnm = e.getAttributes();
                for (int i = 0; i < nnm.getLength(); i++) {
                    Attr a = (Attr) nnm.item(i);
                    String ans = a.getNamespaceURI();
                    if (ans != null) {
                        String apre = a.getPrefix();
                        if (apre != null
                                && (apre.equals(XMLConstants.XML_PREFIX)
                                    || apre.equals(XMLConstants.XMLNS_PREFIX))
                                || ans.equals(XMLConstants.XMLNS_NAMESPACE_URI)) {
                            continue;
                        }
                        String aprens = apre == null ? null : ae.lookupNamespaceURI(apre);
                        if (apre == null
                                || aprens == null
                                || !aprens.equals(ans)) {
                            String newpre = ae.lookupPrefix(ans);
                            if (newpre != null) {
                                a.setPrefix(newpre);
                            } else {
                                if (apre != null
                                        && ae.lookupNamespaceURI(apre) == null) {
                                    e.setAttributeNS
                                        (XMLConstants.XMLNS_NAMESPACE_URI,
                                         XMLConstants.XMLNS_PREFIX + ':' + apre,
                                         ans);
                                } else {
                                    int index = 1;
                                    for (;;) {
                                        newpre = "NS" + index;
                                        if (ae.lookupPrefix(newpre) == null) {
                                            e.setAttributeNS
                                                (XMLConstants.XMLNS_NAMESPACE_URI,
                                                 XMLConstants.XMLNS_PREFIX + ':' + newpre,
                                                 ans);
                                            a.setPrefix(newpre);
                                            break;
                                        }
                                    }
                                }
                            }
                        }
                    } else {
                        if (a.getLocalName() == null) {
                            // report error
                        }
                    }
                }
            }
        }

        // check well-formedness
        nnm = e.getAttributes();
        for (int i = 0; i < nnm.getLength(); i++) {
            Attr a = (Attr) nnm.item(i);
            if (!checkName(a.getNodeName())) {
                if (errorHandler != null) {
                    if (!errorHandler.handleError(createDOMError(
                            DOMConstants.DOM_INVALID_CHARACTER_IN_NODE_NAME_ERROR,
                            DOMError.SEVERITY_ERROR,
                            "wf.invalid.name",
                            new Object[] { a.getNodeName() },
                            a,
                            null))) {
                        return false;
                    }
                }
            }
            if (!checkChars(a.getNodeValue())) {
                if (errorHandler != null) {
                    if (!errorHandler.handleError(createDOMError(
                            DOMConstants.DOM_INVALID_CHARACTER_ERROR,
                            DOMError.SEVERITY_ERROR,
                            "wf.invalid.character",
                            new Object[] { new Integer(Node.ATTRIBUTE_NODE),
                                           a.getNodeName(),
                                           a.getNodeValue() },
                            a,
                            null))) {
                        return false;
                    }
                }
            }
        }
        for (Node m = e.getFirstChild(); m != null; m = m.getNextSibling()) {
            int nt = m.getNodeType();
            String s;
            switch (nt) {
                case Node.TEXT_NODE:
                    s = m.getNodeValue();
                    if (!checkChars(s)) {
                        if (errorHandler != null) {
                            if (!errorHandler.handleError(createDOMError(
                                    DOMConstants.DOM_INVALID_CHARACTER_ERROR,
                                    DOMError.SEVERITY_ERROR,
                                    "wf.invalid.character",
                                    new Object[] { new Integer(m.getNodeType()),
                                                   m.getNodeName(),
                                                   s },
                                    m,
                                    null))) {
                                return false;
                            }
                        }
                    }
                    break;
                case Node.COMMENT_NODE:
                    s = m.getNodeValue();
                    if (!checkChars(s)
                            || s.indexOf(XMLConstants.XML_DOUBLE_DASH) != -1
                            || s.charAt(s.length() - 1) == '-') {
                        if (errorHandler != null) {
                            if (!errorHandler.handleError(createDOMError(
                                    DOMConstants.DOM_INVALID_CHARACTER_ERROR,
                                    DOMError.SEVERITY_ERROR,
                                    "wf.invalid.character",
                                    new Object[] { new Integer(m.getNodeType()),
                                                   m.getNodeName(),
                                                   s },
                                    m,
                                    null))) {
                                return false;
                            }
                        }
                    }
                    break;
                case Node.CDATA_SECTION_NODE:
                    s = m.getNodeValue();
                    if (!checkChars(s)
                            || s.indexOf(XMLConstants.XML_CDATA_END) != -1) {
                        if (errorHandler != null) {
                            if (!errorHandler.handleError(createDOMError(
                                    DOMConstants.DOM_INVALID_CHARACTER_ERROR,
                                    DOMError.SEVERITY_ERROR,
                                    "wf.invalid.character",
                                    new Object[] { new Integer(m.getNodeType()),
                                                   m.getNodeName(),
                                                   s },
                                    m,
                                    null))) {
                                return false;
                            }
                        }
                    }
                    break;
                case Node.PROCESSING_INSTRUCTION_NODE:
                    if (m.getNodeName().equalsIgnoreCase
                            (XMLConstants.XML_PREFIX)) {
                        if (errorHandler != null) {
                            if (!errorHandler.handleError(createDOMError(
                                    DOMConstants.DOM_INVALID_CHARACTER_IN_NODE_NAME_ERROR,
                                    DOMError.SEVERITY_ERROR,
                                    "wf.invalid.name",
                                    new Object[] { m.getNodeName() },
                                    m,
                                    null))) {
                                return false;
                            }
                        }
                    }
                    s = m.getNodeValue();
                    if (!checkChars(s)
                            || s.indexOf(XMLConstants
                                .XML_PROCESSING_INSTRUCTION_END) != -1) {
                        if (errorHandler != null) {
                            if (!errorHandler.handleError(createDOMError(
                                    DOMConstants.DOM_INVALID_CHARACTER_ERROR,
                                    DOMError.SEVERITY_ERROR,
                                    "wf.invalid.character",
                                    new Object[] { new Integer(m.getNodeType()),
                                                   m.getNodeName(),
                                                   s },
                                    m,
                                    null))) {
                                return false;
                            }
                        }
                    }
                    break;
                case Node.ELEMENT_NODE:
                    if (!checkName(m.getNodeName())) {
                        if (errorHandler != null) {
                            if (!errorHandler.handleError(createDOMError(
                                    DOMConstants.DOM_INVALID_CHARACTER_IN_NODE_NAME_ERROR,
                                    DOMError.SEVERITY_ERROR,
                                    "wf.invalid.name",
                                    new Object[] { m.getNodeName() },
                                    m,
                                    null))) {
                                return false;
                            }
                        }
                    }
                    if (!normalizeDocument((Element) m,
                                           cdataSections,
                                           comments,
                                           elementContentWhitepace,
                                           namespaceDeclarations,
                                           namespaces,
                                           splitCdataSections,
                                           errorHandler)) {
                        return false;
                    }
                    break;
            }
        }
        return true;
    }

    /**
     * Splits the given CDATA node if required.
     */
    protected boolean splitCdata(Element e,
                                 Node n,
                                 DOMErrorHandler errorHandler) {
        String s2 = n.getNodeValue();
        int index = s2.indexOf(XMLConstants.XML_CDATA_END);
        if (index != -1) {
            String before = s2.substring(0, index + 2);
            String after = s2.substring(index + 2);
            n.setNodeValue(before);
            Node next = n.getNextSibling();
            if (next == null) {
                e.appendChild(createCDATASection(after));
            } else {
                e.insertBefore(createCDATASection(after),
                               next);
            }
            if (errorHandler != null) {
                if (!errorHandler.handleError(createDOMError(
                    DOMConstants.DOM_CDATA_SECTIONS_SPLITTED_ERROR,
                    DOMError.SEVERITY_WARNING,
                    "cdata.section.split",
                    new Object[] {},
                    n,
                    null))) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Checks that the characters in the given string are all valid
     * content characters.
     */
    protected boolean checkChars(String s) {
        int len = s.length();
        if (xmlVersion.equals(XMLConstants.XML_VERSION_11)) {
            for (int i = 0; i < len; i++) {
                if (!DOMUtilities.isXML11Character(s.charAt(i))) {
                    return false;
                }
            }
        } else {
            // assume XML 1.0
            for (int i = 0; i < len; i++) {
                if (!DOMUtilities.isXMLCharacter(s.charAt(i))) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Checks that the given string is a valid XML name.
     */
    protected boolean checkName(String s) {
        if (xmlVersion.equals(XMLConstants.XML_VERSION_11)) {
            return DOMUtilities.isValidName11(s);
        }
        // assume XML 1.0
        return DOMUtilities.isValidName(s);
    }

    /**
     * Creates a DOMError object with the given parameters.
     */
    protected DOMError createDOMError(String type,
                                      short severity,
                                      String key,
                                      Object[] args,
                                      Node related,
                                      Exception e) {
        try {
            return new DocumentError(type,
                                     severity,
                                     getCurrentDocument().formatMessage(key, args),
                                     related,
                                     e);
        } catch (Exception ex) {
            return new DocumentError(type,
                                     severity,
                                     key,
                                     related,
                                     e);
        }
    }

    /**
     * <b>DOM</b>: Implements {@link org.w3c.dom.Node#setTextContent(String)}.
     */
    public void setTextContent(String s) throws DOMException {
    }

    /**
     * Sets the XBLManager used for this document.
     */
    public void setXBLManager(XBLManager m) {
        boolean wasProcessing = xblManager.isProcessing();
        xblManager.stopProcessing();
        if (m == null) {
            m = new GenericXBLManager();
        }
        xblManager = m;
        if (wasProcessing) {
            xblManager.startProcessing();
        }
    }

    /**
     * Returns the XBLManager used for this document.
     */
    public XBLManager getXBLManager() {
        return xblManager;
    }

    /**
     * DOMError implementation.
     */
    protected class DocumentError implements DOMError {

        /**
         * The error type.
         */
        protected String type;

        /**
         * The error severity.
         */
        protected short severity;

        /**
         * The error message.
         */
        protected String message;

        /**
         * The error related data.
         */
        protected Node relatedNode;

        /**
         * The exception which cuased this error.
         */
        protected Object relatedException;

        /**
         * The DOMLocator for this error.
         */
        protected DOMLocator domLocator;

        /**
         * Creates a new DocumentError object.
         */
        public DocumentError(String type,
                             short severity,
                             String message,
                             Node relatedNode,
                             Exception relatedException) {
            this.type = type;
            this.severity = severity;
            this.message = message;
            this.relatedNode = relatedNode;
            this.relatedException = relatedException;
        }

        public String getType() {
            return type;
        }

        public short getSeverity() {
            return severity;
        }

        public String getMessage() {
            return message;
        }

        public Object getRelatedData() {
            return relatedNode;
        }

        public Object getRelatedException() {
            return relatedException;
        }

        public DOMLocator getLocation() {
            if (domLocator == null) {
                domLocator = new ErrorLocation(relatedNode);
            }
            return domLocator;
        }

        /**
         * The DOMLocator implementation.
         */
        protected class ErrorLocation implements DOMLocator {

            /**
             * The node that caused the error.
             */
            protected Node node;

            /**
             * Create a new ErrorLocation object.
             */
            public ErrorLocation(Node n) {
                node = n;
            }

            /**
             * Get the line number of the error node.
             */
            public int getLineNumber() {
                return -1;
            }

            /**
             * Get the column number of the error node.
             */
            public int getColumnNumber() {
                return -1;
            }

            /**
             * Get the byte offset of the error node.
             */
            public int getByteOffset() {
                return -1;
            }

            /**
             * Get the UTF-16 offset of the error node.
             */
            public int getUtf16Offset() {
                return -1;
            }

            /**
             * Get the node.
             */
            public Node getRelatedNode() {
                return node;
            }

            /**
             * Get the document URI.
             */
            public String getUri() {
                AbstractDocument doc
                    = (AbstractDocument) node.getOwnerDocument();
                return doc.getDocumentURI();
            }
        }
    }

    /**
     * DOMConfiguration for this document.
     */
    protected class DocumentConfiguration implements DOMConfiguration {

        /**
         * The boolean parameter names.
         */
        protected String[] booleanParamNames = {
            DOMConstants.DOM_CANONICAL_FORM_PARAM,
            DOMConstants.DOM_CDATA_SECTIONS_PARAM,
            DOMConstants.DOM_CHECK_CHARACTER_NORMALIZATION_PARAM,
            DOMConstants.DOM_COMMENTS_PARAM,
            DOMConstants.DOM_DATATYPE_NORMALIZATION_PARAM,
            DOMConstants.DOM_ELEMENT_CONTENT_WHITESPACE_PARAM,
            DOMConstants.DOM_ENTITIES_PARAM,
            DOMConstants.DOM_INFOSET_PARAM,
            DOMConstants.DOM_NAMESPACES_PARAM,
            DOMConstants.DOM_NAMESPACE_DECLARATIONS_PARAM,
            DOMConstants.DOM_NORMALIZE_CHARACTERS_PARAM,
            DOMConstants.DOM_SPLIT_CDATA_SECTIONS_PARAM,
            DOMConstants.DOM_VALIDATE_PARAM,
            DOMConstants.DOM_VALIDATE_IF_SCHEMA_PARAM,
            DOMConstants.DOM_WELL_FORMED_PARAM
        };

        /**
         * The boolean parameter values.
         */
        protected boolean[] booleanParamValues = {
            false,      // canonical-form
            true,       // cdata-sections
            false,      // check-character-normalization
            true,       // comments
            false,      // datatype-normalization
            false,      // element-content-whitespace
            true,       // entities
            false,      // infoset
            true,       // namespaces
            true,       // namespace-declarations
            false,      // normalize-characters
            true,       // split-cdata-sections
            false,      // validate
            false,      // validate-if-schema
            true        // well-formed
        };

        /**
         * The read-onlyness of the boolean parameters.
         */
        protected boolean[] booleanParamReadOnly = {
            true,       // canonical-form
            false,      // cdata-sections
            true,       // check-character-normalization
            false,      // comments
            true,       // datatype-normalization
            false,      // element-content-whitespace
            false,      // entities
            false,      // infoset
            false,      // namespaces
            false,      // namespace-declarations
            true,       // normalize-characters
            false,      // split-cdata-sections
            true,       // validate
            true,       // validate-if-schema
            false       // well-formed
        };

        /**
         * Map of parameter names to array indexes.
         */
        protected Map booleanParamIndexes = new HashMap();
        {
            for (int i = 0; i < booleanParamNames.length; i++) {
                booleanParamIndexes.put(booleanParamNames[i], new Integer(i));
            }
        }

        /**
         * Value of the 'error-handler' parameter.
         */
        protected Object errorHandler;

        /**
         * The DOMStringList object containing the parameter names.
         */
        protected ParameterNameList paramNameList;

        /**
         * Sets the given parameter.
         */
        public void setParameter(String name, Object value) {
            if (DOMConstants.DOM_ERROR_HANDLER_PARAM.equals(name)) {
                if (value != null && !(value instanceof DOMErrorHandler)) {
                    throw createDOMException
                        ((short) 17 /*DOMException.TYPE_MISMATCH_ERR*/,
                         "domconfig.param.type",
                         new Object[] { name });
                }
                errorHandler = value;
                return;
            }
            Integer i = (Integer) booleanParamIndexes.get(name);
            if (i == null) {
                throw createDOMException
                    (DOMException.NOT_FOUND_ERR,
                     "domconfig.param.not.found",
                     new Object[] { name });
            }
            if (value == null) {
                throw createDOMException
                    (DOMException.NOT_SUPPORTED_ERR,
                     "domconfig.param.value",
                     new Object[] { name });
            }
            if (!(value instanceof Boolean)) {
                throw createDOMException
                    ((short) 17 /*DOMException.TYPE_MISMATCH_ERR*/,
                     "domconfig.param.type",
                     new Object[] { name });
            }
            int index = i.intValue();
            boolean val = ((Boolean) value).booleanValue();
            if (booleanParamReadOnly[index]
                    && booleanParamValues[index] != val) {
                throw createDOMException
                    (DOMException.NOT_SUPPORTED_ERR,
                     "domconfig.param.value",
                     new Object[] { name });
            }
            booleanParamValues[index] = val;
            if (name.equals(DOMConstants.DOM_INFOSET_PARAM)) {
                setParameter(DOMConstants.DOM_VALIDATE_IF_SCHEMA_PARAM, Boolean.FALSE);
                setParameter(DOMConstants.DOM_ENTITIES_PARAM, Boolean.FALSE);
                setParameter(DOMConstants.DOM_DATATYPE_NORMALIZATION_PARAM, Boolean.FALSE);
                setParameter(DOMConstants.DOM_CDATA_SECTIONS_PARAM, Boolean.FALSE);
                setParameter(DOMConstants.DOM_WELL_FORMED_PARAM, Boolean.TRUE);
                setParameter(DOMConstants.DOM_ELEMENT_CONTENT_WHITESPACE_PARAM, Boolean.TRUE);
                setParameter(DOMConstants.DOM_COMMENTS_PARAM, Boolean.TRUE);
                setParameter(DOMConstants.DOM_NAMESPACES_PARAM, Boolean.TRUE);
            }
        }

        /**
         * Gets the value of the given parameter.
         */
        public Object getParameter(String name) {
            if (DOMConstants.DOM_ERROR_HANDLER_PARAM.equals(name)) {
                return errorHandler;
            }
            Integer index = (Integer) booleanParamIndexes.get(name);
            if (index == null) {
                throw createDOMException
                    (DOMException.NOT_FOUND_ERR,
                     "domconfig.param.not.found",
                     new Object[] { name });
            }
            return booleanParamValues[index.intValue()] ? Boolean.TRUE
                                                        : Boolean.FALSE;
        }

        /**
         * Gets the boolean value of the given parameter.
         */
        public boolean getBooleanParameter(String name) {
            Boolean b = (Boolean) getParameter(name);
            return b.booleanValue();
        }

        /**
         * Returns whether the given parameter can be set to the given value.
         */
        public boolean canSetParameter(String name, Object value) {
            if (name.equals(DOMConstants.DOM_ERROR_HANDLER_PARAM)) {
                return value == null || value instanceof DOMErrorHandler;
            }
            Integer i = (Integer) booleanParamIndexes.get(name);
            if (i == null || value == null || !(value instanceof Boolean)) {
                return false;
            }
            int index = i.intValue();
            boolean val = ((Boolean) value).booleanValue();
            return !booleanParamReadOnly[index]
                || booleanParamValues[index] == val;
        }

        /**
         * Returns a DOMStringList of parameter names.
         */
        public DOMStringList getParameterNames() {
            if (paramNameList == null) {
                paramNameList = new ParameterNameList();
            }
            return paramNameList;
        }

        /**
         * Class to expose the parameter names.
         */
        protected class ParameterNameList implements DOMStringList {

            /**
             * Returns the parameter name at the given index.
             */
            public String item(int index) {
                if (index < 0) {
                    return null;
                }
                if (index < booleanParamNames.length) {
                    return booleanParamNames[index];
                }
                if (index == booleanParamNames.length) {
                    return DOMConstants.DOM_ERROR_HANDLER_PARAM;
                }
                return null;
            }

            /**
             * Returns the number of parameter names in the list.
             */
            public int getLength() {
                return booleanParamNames.length + 1;
            }

            /**
             * Returns whether the given parameter name is in the list.
             */
            public boolean contains(String s) {
                if (DOMConstants.DOM_ERROR_HANDLER_PARAM.equals(s)) {
                    return true;
                }
                for (int i = 0; i < booleanParamNames.length; i++) {
                    if (booleanParamNames[i].equals(s)) {
                        return true;
                    }
                }
                return false;
            }
        }
    }

    /**
     * <b>DOM</b>: Implements
     * {@link org.w3c.dom.xpath.XPathEvaluator#createExpression(String,XPathNSResolver)}.
     */
    public XPathExpression createExpression(String expression,
                                            XPathNSResolver resolver)
            throws DOMException, XPathException {
        return new XPathExpr(expression, resolver);
    }

    /**
     * <b>DOM</b>: Implements
     * {@link org.w3c.dom.xpath.XPathEvaluator#createNSResolver(Node)}.
     */
    public XPathNSResolver createNSResolver(Node n) {
        return new XPathNodeNSResolver(n);
    }

    /**
     * <b>DOM</b>: Implements
     * {@link org.w3c.dom.xpath.XPathEvaluator#evaluate(String,Node,XPathNSResolver,short,Object)}.
     */
    public Object evaluate(String expression,
                           Node contextNode,
                           XPathNSResolver resolver,
                           short type,
                           Object result)
            throws XPathException, DOMException {
        XPathExpression xpath = createExpression(expression, resolver);
        return xpath.evaluate(contextNode, type, result);
    }

    /**
     * Creates an exception with the appropriate error message.
     */
    public XPathException createXPathException(short type,
                                               String key,
                                               Object[] args) {
        try {
            return new XPathException(type, formatMessage(key, args));
        } catch (Exception e) {
            return new XPathException(type, key);
        }
    }

    /**
     * A compiled XPath expression.
     */
    protected class XPathExpr implements XPathExpression {

        /**
         * The compiled XPath expression.
         */
        protected XPath xpath;

        /**
         * The namespace resolver.
         */
        protected XPathNSResolver resolver;

        /**
         * The Xalan prefix resolver.
         */
        protected NSPrefixResolver prefixResolver;

        /**
         * The XPathContext object.
         */
        protected XPathContext context;

        /**
         * Creates a new XPathExpr object.
         */
        public XPathExpr(String expr, XPathNSResolver res)
                throws DOMException, XPathException {
            resolver = res;
            prefixResolver = new NSPrefixResolver();
            try {
                xpath = new XPath(expr, null, prefixResolver, XPath.SELECT);
                context = new XPathContext();
            } catch (javax.xml.transform.TransformerException te) {
                throw createXPathException
                    (XPathException.INVALID_EXPRESSION_ERR,
                     "xpath.invalid.expression",
                     new Object[] { expr, te.getMessage() });
            }
        }

        /**
         * <b>DOM</b>: Implements
         * {@link org.w3c.dom.xpath.XPathExpression#evaluate(Node,short,Object)}.
         */
        public Object evaluate(Node contextNode, short type, Object res)
                throws XPathException, DOMException {
            if (contextNode.getNodeType() != DOCUMENT_NODE
                    && contextNode.getOwnerDocument() != AbstractDocument.this
                    || contextNode.getNodeType() == DOCUMENT_NODE
                    && contextNode != AbstractDocument.this) {
                throw createDOMException
                    (DOMException.WRONG_DOCUMENT_ERR,
                     "node.from.wrong.document",
                     new Object[] { new Integer(contextNode.getNodeType()),
                                    contextNode.getNodeName() });
            }
            if (type < 0 || type > 9) {
                throw createDOMException(DOMException.NOT_SUPPORTED_ERR,
                                         "xpath.invalid.result.type",
                                         new Object[] { new Integer(type) });
            }
            switch (contextNode.getNodeType()) {
                case ENTITY_REFERENCE_NODE:
                case ENTITY_NODE:
                case DOCUMENT_TYPE_NODE:
                case DOCUMENT_FRAGMENT_NODE:
                case NOTATION_NODE:
                    throw createDOMException
                        (DOMException.NOT_SUPPORTED_ERR,
                         "xpath.invalid.context.node",
                         new Object[] { new Integer(contextNode.getNodeType()),
                                        contextNode.getNodeName() });
            }
            context.reset();
            XObject result = null;
            try {
                result = xpath.execute(context, contextNode, prefixResolver);
            } catch (javax.xml.transform.TransformerException te) {
                throw createXPathException
                    (XPathException.INVALID_EXPRESSION_ERR,
                     "xpath.error",
                     new Object[] { xpath.getPatternString(),
                                    te.getMessage() });
            }
            try {
                switch (type) {
                    case XPathResult.ANY_UNORDERED_NODE_TYPE:
                    case XPathResult.FIRST_ORDERED_NODE_TYPE:
                        return convertSingleNode(result, type);
                    case XPathResult.BOOLEAN_TYPE:
                        return convertBoolean(result);
                    case XPathResult.NUMBER_TYPE:
                        return convertNumber(result);
                    case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
                    case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
                    case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
                    case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
                        return convertNodeIterator(result, type);
                    case XPathResult.STRING_TYPE:
                        return convertString(result);
                    case XPathResult.ANY_TYPE:
                        switch (result.getType()) {
                            case XObject.CLASS_BOOLEAN:
                                return convertBoolean(result);
                            case XObject.CLASS_NUMBER:
                                return convertNumber(result);
                            case XObject.CLASS_STRING:
                                return convertString(result);
                            case XObject.CLASS_NODESET:
                                return convertNodeIterator
                                    (result,
                                     XPathResult.UNORDERED_NODE_ITERATOR_TYPE);
                        }
                }
            } catch (javax.xml.transform.TransformerException te) {
                throw createXPathException
                    (XPathException.TYPE_ERR,
                     "xpath.cannot.convert.result",
                     new Object[] { new Integer(type),
                                    te.getMessage() });
            }
            return null;
        }

        /**
         * Converts an XObject to a single node XPathResult.
         */
        protected Result convertSingleNode(XObject xo, short type)
                throws javax.xml.transform.TransformerException {
            return new Result(xo.nodelist().item(0), type);
        }

        /**
         * Converts an XObject to a boolean XPathResult.
         */
        protected Result convertBoolean(XObject xo)
                throws javax.xml.transform.TransformerException {
            return new Result(xo.bool());
        }

        /**
         * Converts an XObject to a number XPathResult.
         */
        protected Result convertNumber(XObject xo)
                throws javax.xml.transform.TransformerException {
            return new Result(xo.num());
        }

        /**
         * Converts an XObject to a string XPathResult.
         */
        protected Result convertString(XObject xo) {
            return new Result(xo.str());
        }

        /**
         * Converts an XObject to a node iterator XPathResult.
         */
        protected Result convertNodeIterator(XObject xo, short type)
                throws javax.xml.transform.TransformerException {
            return new Result(xo.nodelist(), type);
        }

        /**
         * XPathResult implementation.
         * XXX Namespace nodes are not handled correctly, since Xalan returns
         *     namespace nodes as simply the attribute node that caused the
         *     namespace to be in scope on the element in question.  Thus it
         *     is impossible to tell the difference between a selected
         *     attribute that begins with 'xmlns' and an XPath namespace node.
         */
        public class Result implements XPathResult {

            /**
             * The result type.
             */
            protected short resultType;

            /**
             * The number value.
             */
            protected double numberValue;

            /**
             * The string value.
             */
            protected String stringValue;

            /**
             * The boolean value.
             */
            protected boolean booleanValue;

            /**
             * The single node value.
             */
            protected Node singleNodeValue;

            /**
             * The NodeList for iterators.
             */
            protected NodeList iterator;

            /**
             * The position of the iterator.
             */
            protected int iteratorPosition;

            /**
             * Creates a new single node Result object.
             */
            public Result(Node n, short type) {
                resultType = type;
                singleNodeValue = n;
            }

            /**
             * Creates a new boolean Result object.
             */
            public Result(boolean b)
                    throws javax.xml.transform.TransformerException {
                resultType = BOOLEAN_TYPE;
                booleanValue = b;
            }

            /**
             * Creates a new number Result object.
             */
            public Result(double d)
                    throws javax.xml.transform.TransformerException {
                resultType = NUMBER_TYPE;
                numberValue = d;
            }

            /**
             * Creates a new string Result object.
             */
            public Result(String s) {
                resultType = STRING_TYPE;
                stringValue = s;
            }

            /**
             * Creates a new node iterator Result object.
             */
            public Result(NodeList nl, short type) {
                resultType = type;
                iterator = nl;
            }

            /**
             * Gets the result type.
             */
            public short getResultType() {
                return resultType;
            }

            /**
             * Gets the boolean value.
             */
            public boolean getBooleanValue() {
                if (resultType != BOOLEAN_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return booleanValue;
            }

            /**
             * Gets the number value.
             */
            public double getNumberValue() {
                if (resultType != NUMBER_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return numberValue;
            }

            /**
             * Gets the string value.
             */
            public String getStringValue() {
                if (resultType != STRING_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return stringValue;
            }

            /**
             * Gets the single node value.
             */
            public Node getSingleNodeValue() {
                if (resultType != ANY_UNORDERED_NODE_TYPE
                        && resultType != FIRST_ORDERED_NODE_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return singleNodeValue;
            }

            /**
             * Returns whether the iterator has been invalidated by
             * document modifications.
             */
            public boolean getInvalidIteratorState() {
                return false;
            }

            /**
             * Returns the length of the snapshot.
             */
            public int getSnapshotLength() {
                if (resultType != UNORDERED_NODE_SNAPSHOT_TYPE
                        && resultType != ORDERED_NODE_SNAPSHOT_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return iterator.getLength();
            }

            /**
             * <b>DOM</b>: Implement
             * {@link org.w3c.dom.xpath.XPathResult#iterateNext()}.
             */
            public Node iterateNext() {
                if (resultType != UNORDERED_NODE_ITERATOR_TYPE
                        && resultType != ORDERED_NODE_ITERATOR_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return iterator.item(iteratorPosition++);
            }

            /**
             * Returns the <code>i</code>th item in the snapshot.
             */
            public Node snapshotItem(int i) {
                if (resultType != UNORDERED_NODE_SNAPSHOT_TYPE
                        && resultType != ORDERED_NODE_SNAPSHOT_TYPE) {
                    throw createXPathException
                        (XPathException.TYPE_ERR,
                         "xpath.invalid.result.type",
                         new Object[] { new Integer(resultType) });
                }
                return iterator.item(i);
            }
        }

        /**
         * Xalan prefix resolver.
         */
        protected class NSPrefixResolver implements PrefixResolver {

            /**
             * Get the base URI for this resolver.  Since this resolver isn't
             * associated with a particular node, returns null.
             */
            public String getBaseIdentifier() {
                return null;
            }

            /**
             * Resolves the given namespace prefix.
             */
            public String getNamespaceForPrefix(String prefix) {
                if (resolver == null) {
                    return null;
                }
                return resolver.lookupNamespaceURI(prefix);
            }

            /**
             * Resolves the given namespace prefix.
             */
            public String getNamespaceForPrefix(String prefix, Node context) {
                // ignore the context node
                if (resolver == null) {
                    return null;
                }
                return resolver.lookupNamespaceURI(prefix);
            }

            /**
             * Returns whether this PrefixResolver handles a null prefix.
             */
            public boolean handlesNullPrefixes() {
                return false;
            }
        }
    }

    /**
     * An XPathNSResolver that uses Node.lookupNamespaceURI.
     */
    protected class XPathNodeNSResolver implements XPathNSResolver {

        /**
         * The context node for namespace prefix resolution.
         */
        protected Node contextNode;

        /**
         * Creates a new XPathNodeNSResolver object.
         */
        public XPathNodeNSResolver(Node n) {
            contextNode = n;
        }

        /**
         * <b>DOM</b>: Implements
         * {@link org.w3c.dom.xpath.XPathNSResolver#lookupNamespaceURI(String)}.
         */
        public String lookupNamespaceURI(String prefix) {
            return ((AbstractNode) contextNode).lookupNamespaceURI(prefix);
        }
    }

    // NodeXBL //////////////////////////////////////////////////////////////

    /**
     * Get the parent of this node in the fully flattened tree.
     */
    public Node getXblParentNode() {
        return xblManager.getXblParentNode(this);
    }

    /**
     * Get the list of child nodes of this node in the fully flattened tree.
     */
    public NodeList getXblChildNodes() {
        return xblManager.getXblChildNodes(this);
    }

    /**
     * Get the list of child nodes of this node in the fully flattened tree
     * that are within the same shadow scope.
     */
    public NodeList getXblScopedChildNodes() {
        return xblManager.getXblScopedChildNodes(this);
    }

    /**
     * Get the first child node of this node in the fully flattened tree.
     */
    public Node getXblFirstChild() {
        return xblManager.getXblFirstChild(this);
    }

    /**
     * Get the last child node of this node in the fully flattened tree.
     */
    public Node getXblLastChild() {
        return xblManager.getXblLastChild(this);
    }

    /**
     * Get the node which directly precedes the current node in the
     * xblParentNode's xblChildNodes list.
     */
    public Node getXblPreviousSibling() {
        return xblManager.getXblPreviousSibling(this);
    }

    /**
     * Get the node which directly follows the current node in the
     * xblParentNode's xblChildNodes list.
     */
    public Node getXblNextSibling() {
        return xblManager.getXblNextSibling(this);
    }

    /**
     * Get the first element child of this node in the fully flattened tree.
     */
    public Element getXblFirstElementChild() {
        return xblManager.getXblFirstElementChild(this);
    }

    /**
     * Get the last element child of this node in the fully flattened tree.
     */
    public Element getXblLastElementChild() {
        return xblManager.getXblLastElementChild(this);
    }

    /**
     * Get the first element that precedes the current node in the
     * xblParentNode's xblChildNodes list.
     */
    public Element getXblPreviousElementSibling() {
        return xblManager.getXblPreviousElementSibling(this);
    }

    /**
     * Get the first element that follows the current node in the
     * xblParentNode's xblChildNodes list.
     */
    public Element getXblNextElementSibling() {
        return xblManager.getXblNextElementSibling(this);
    }

    /**
     * Get the bound element whose shadow tree this current node resides in.
     */
    public Element getXblBoundElement() {
        return xblManager.getXblBoundElement(this);
    }

    /**
     * Get the shadow tree of this node.
     */
    public Element getXblShadowTree() {
        return xblManager.getXblShadowTree(this);
    }

    /**
     * Get the xbl:definition elements currently binding this element.
     */
    public NodeList getXblDefinitions() {
        return xblManager.getXblDefinitions(this);
    }

    // Serializable /////////////////////////////////////////////////

    private void writeObject(ObjectOutputStream s) throws IOException {
        s.defaultWriteObject();

        s.writeObject(implementation.getClass().getName());
    }

    private void readObject(ObjectInputStream s)
        throws IOException, ClassNotFoundException {
        s.defaultReadObject();

        localizableSupport = new LocalizableSupport
            (RESOURCES, getClass().getClassLoader());

        Class c = Class.forName((String)s.readObject());

        try {
            Method m = c.getMethod("getDOMImplementation", (Class[])null);
            implementation = (DOMImplementation)m.invoke(null, (Object[])null);
        } catch (Exception e) {
            try {
                implementation = (DOMImplementation)c.newInstance();
            } catch (Exception ex) {
            }
        }
    }
}
