java/11 : java.xml/com/sun/org/apache/xerces/internal/dom/NodeImpl.java

NodeImpl
https://openjdk.java.net/
GPLv2 + Classpath Exception
/*
 * Copyright (c) 2015, 2019 Oracle and/or its affiliates. All rights reserved.
 */
 /*
 * 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 com.sun.org.apache.xerces.internal.dom;

import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Map;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.UserDataHandler;
import org.w3c.dom.events.Event;
import org.w3c.dom.events.EventListener;
import org.w3c.dom.events.EventTarget;

NodeImpl provides the basic structure of a DOM tree. It is never used
directly, but instead is subclassed to add type and data
information, and additional methods, appropriate to each node of
the tree. Only its subclasses should be instantiated -- and those,
with the exception of Document itself, only through a specific
Document's factory methods.

The Node interface provides shared behaviors such as siblings and
children, both for consistancy and so that the most common tree
operations may be performed without constantly having to downcast
to specific node types. When there is no obvious mapping for one of
these queries, it will respond with null.
Note that the default behavior is that children are forbidden. To
permit them, the subclass ParentNode overrides several methods.

NodeImpl also implements NodeList, so it can return itself in
response to the getChildNodes() query. This eliminiates the need
for a separate ChildNodeList object. Note that this is an
IMPLEMENTATION DETAIL; applications should _never_ assume that
this identity exists.

All nodes in a single document must originate
in that document. (Note that this is much tighter than "must be
same implementation") Nodes are all aware of their ownerDocument,
and attempts to mismatch will throw WRONG_DOCUMENT_ERR.

However, to save memory not all nodes always have a direct reference
to their ownerDocument. When a node is owned by another node it relies
on its owner to store its ownerDocument. Parent nodes always store it
though, so there is never more than one level of indirection.
And when a node doesn't have an owner, ownerNode refers to its
ownerDocument.

This class doesn't directly support mutation events, however, it still
implements the EventTarget interface and forward all related calls to the
document so that the document class do so.
Author: Arnaud  Le Hors, IBM, Joe Kesselman, IBM
@xerces.internal 
Since:  PR-DOM-Level-1-19980818.
@LastModified : Apr 2019/**
 * NodeImpl provides the basic structure of a DOM tree. It is never used
 * directly, but instead is subclassed to add type and data
 * information, and additional methods, appropriate to each node of
 * the tree. Only its subclasses should be instantiated -- and those,
 * with the exception of Document itself, only through a specific
 * Document's factory methods.
 * <P>
 * The Node interface provides shared behaviors such as siblings and
 * children, both for consistancy and so that the most common tree
 * operations may be performed without constantly having to downcast
 * to specific node types. When there is no obvious mapping for one of
 * these queries, it will respond with null.
 * Note that the default behavior is that children are forbidden. To
 * permit them, the subclass ParentNode overrides several methods.
 * <P>
 * NodeImpl also implements NodeList, so it can return itself in
 * response to the getChildNodes() query. This eliminiates the need
 * for a separate ChildNodeList object. Note that this is an
 * IMPLEMENTATION DETAIL; applications should _never_ assume that
 * this identity exists.
 * <P>
 * All nodes in a single document must originate
 * in that document. (Note that this is much tighter than "must be
 * same implementation") Nodes are all aware of their ownerDocument,
 * and attempts to mismatch will throw WRONG_DOCUMENT_ERR.
 * <P>
 * However, to save memory not all nodes always have a direct reference
 * to their ownerDocument. When a node is owned by another node it relies
 * on its owner to store its ownerDocument. Parent nodes always store it
 * though, so there is never more than one level of indirection.
 * And when a node doesn't have an owner, ownerNode refers to its
 * ownerDocument.
 * <p>
 * This class doesn't directly support mutation events, however, it still
 * implements the EventTarget interface and forward all related calls to the
 * document so that the document class do so.
 *
 * @xerces.internal
 *
 * @author Arnaud  Le Hors, IBM
 * @author Joe Kesselman, IBM
 * @since  PR-DOM-Level-1-19980818.
 * @LastModified: Apr 2019
 */
public abstract class NodeImpl
    implements Node, NodeList, EventTarget, Cloneable, Serializable{

    //
    // Constants
    //


    // TreePosition Constants.
    // Taken from DOM L3 Node interface.
    The node precedes the reference node.
/**
     * The node precedes the reference node.
     */
    public static final short TREE_POSITION_PRECEDING   = 0x01;
    The node follows the reference node.
/**
     * The node follows the reference node.
     */
    public static final short TREE_POSITION_FOLLOWING   = 0x02;
    The node is an ancestor of the reference node.
/**
     * The node is an ancestor of the reference node.
     */
    public static final short TREE_POSITION_ANCESTOR    = 0x04;
    The node is a descendant of the reference node.
/**
     * The node is a descendant of the reference node.
     */
    public static final short TREE_POSITION_DESCENDANT  = 0x08;
    The two nodes have an equivalent position. This is the case of two
attributes that have the same ownerElement, and two
nodes that are the same.
/**
     * The two nodes have an equivalent position. This is the case of two
     * attributes that have the same <code>ownerElement</code>, and two
     * nodes that are the same.
     */
    public static final short TREE_POSITION_EQUIVALENT  = 0x10;
    The two nodes are the same. Two nodes that are the same have an
equivalent position, though the reverse may not be true.
/**
     * The two nodes are the same. Two nodes that are the same have an
     * equivalent position, though the reverse may not be true.
     */
    public static final short TREE_POSITION_SAME_NODE   = 0x20;
    The two nodes are disconnected, they do not have any common ancestor.
This is the case of two nodes that are not in the same document.
/**
     * The two nodes are disconnected, they do not have any common ancestor.
     * This is the case of two nodes that are not in the same document.
     */
    public static final short TREE_POSITION_DISCONNECTED = 0x00;

    Serialization version. /** Serialization version. */
    static final long serialVersionUID = -6316591992167219696L;

    // public

    Element definition node type. /** Element definition node type. */
    public static final short ELEMENT_DEFINITION_NODE = 21;

    //
    // Data
    //

    // links

    protected NodeImpl ownerNode; // typically the parent but not always!

    // data

    protected short flags;

    protected final static short READONLY     = 0x1<<0;
    protected final static short SYNCDATA     = 0x1<<1;
    protected final static short SYNCCHILDREN = 0x1<<2;
    protected final static short OWNED        = 0x1<<3;
    protected final static short FIRSTCHILD   = 0x1<<4;
    protected final static short SPECIFIED    = 0x1<<5;
    protected final static short IGNORABLEWS  = 0x1<<6;
    protected final static short HASSTRING    = 0x1<<7;
    protected final static short NORMALIZED = 0x1<<8;
    protected final static short ID           = 0x1<<9;

    //
    // Constructors
    //

    No public constructor; only subclasses of Node should be
instantiated, and those normally via a Document's factory methods

Every Node knows what Document it belongs to.
/**
     * No public constructor; only subclasses of Node should be
     * instantiated, and those normally via a Document's factory methods
     * <p>
     * Every Node knows what Document it belongs to.
     */
    protected NodeImpl(CoreDocumentImpl ownerDocument) {
        // as long as we do not have any owner, ownerNode is our ownerDocument
        ownerNode = ownerDocument;
    } // <init>(CoreDocumentImpl)

    Constructor for serialization. /** Constructor for serialization. */
    public NodeImpl() {}

    //
    // Node methods
    //

    A short integer indicating what type of node this is. The named
constants for this value are defined in the org.w3c.dom.Node interface.
/**
     * A short integer indicating what type of node this is. The named
     * constants for this value are defined in the org.w3c.dom.Node interface.
     */
    public abstract short getNodeType();

    the name of this node.
/**
     * the name of this node.
     */
    public abstract String getNodeName();

    Returns the node value.
Throws: DOMException – (DOMSTRING_SIZE_ERR)/**
     * Returns the node value.
     * @throws DOMException(DOMSTRING_SIZE_ERR)
     */
    public String getNodeValue()
        throws DOMException {
        return null;            // overridden in some subclasses
    }

    Sets the node value.
Throws: DOMException – (NO_MODIFICATION_ALLOWED_ERR)/**
     * Sets the node value.
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR)
     */
    public void setNodeValue(String x)
        throws DOMException {
        // Default behavior is to do nothing, overridden in some subclasses
    }

    Adds a child node to the end of the list of children for this node.
Convenience shorthand for insertBefore(newChild,null).
Throws: DOMException – (HIERARCHY_REQUEST_ERR) if newChild is of a
type that shouldn't be a child of this node.
DOMException – (WRONG_DOCUMENT_ERR) if newChild has a
different owner document than we do.
DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is
read-only.
See Also: 
By default we do not accept any children, ParentNode overrides this.
ParentNode
Returns: newChild, in its new state (relocated, or emptied in the case of
DocumentNode.)/**
     * Adds a child node to the end of the list of children for this node.
     * Convenience shorthand for insertBefore(newChild,null).
     * @see #insertBefore(Node, Node)
     * <P>
     * By default we do not accept any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @return newChild, in its new state (relocated, or emptied in the case of
     * DocumentNode.)
     *
     * @throws DOMException(HIERARCHY_REQUEST_ERR) if newChild is of a
     * type that shouldn't be a child of this node.
     *
     * @throws DOMException(WRONG_DOCUMENT_ERR) if newChild has a
     * different owner document than we do.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node appendChild(Node newChild) throws DOMException {
        return insertBefore(newChild, null);
    }

    Returns a duplicate of a given node. You can consider this a
generic "copy constructor" for nodes. The newly returned object should
be completely independent of the source object's subtree, so changes
in one after the clone has been made will not affect the other.

Note: since we never have any children deep is meaningless here,
ParentNode overrides this behavior.
See Also: 
Example: Cloning a Text node will copy both the node and the text it
contains.

Example: Cloning something that has children -- Element or Attr, for
example -- will _not_ clone those children unless a "deep clone"
has been requested. A shallow clone of an Attr node will yield an
empty Attr of the same name.

NOTE: Clones will always be read/write, even if the node being cloned
is read-only, to permit applications using only the DOM API to obtain
editable copies of locked portions of the tree./**
     * Returns a duplicate of a given node. You can consider this a
     * generic "copy constructor" for nodes. The newly returned object should
     * be completely independent of the source object's subtree, so changes
     * in one after the clone has been made will not affect the other.
     * <P>
     * Note: since we never have any children deep is meaningless here,
     * ParentNode overrides this behavior.
     * @see ParentNode
     *
     * <p>
     * Example: Cloning a Text node will copy both the node and the text it
     * contains.
     * <p>
     * Example: Cloning something that has children -- Element or Attr, for
     * example -- will _not_ clone those children unless a "deep clone"
     * has been requested. A shallow clone of an Attr node will yield an
     * empty Attr of the same name.
     * <p>
     * NOTE: Clones will always be read/write, even if the node being cloned
     * is read-only, to permit applications using only the DOM API to obtain
     * editable copies of locked portions of the tree.
     */
    public Node cloneNode(boolean deep) {

        if (needsSyncData()) {
            synchronizeData();
        }

        NodeImpl newnode;
        try {
            newnode = (NodeImpl)clone();
        }
        catch (CloneNotSupportedException e) {
            // if we get here we have an error in our program we may as well
            // be vocal about it, so that people can take appropriate action.
            throw new RuntimeException("**Internal Error**" + e);
        }

        // Need to break the association w/ original kids
        newnode.ownerNode      = ownerDocument();
        newnode.isOwned(false);

        // By default we make all clones readwrite,
        // this is overriden in readonly subclasses
        newnode.isReadOnly(false);

        ownerDocument().callUserDataHandlers(this, newnode,
                                             UserDataHandler.NODE_CLONED);

        return newnode;

    } // cloneNode(boolean):Node

    Find the Document that this Node belongs to (the document in
whose context the Node was created). The Node may or may not
currently be part of that Document's actual contents.
/**
     * Find the Document that this Node belongs to (the document in
     * whose context the Node was created). The Node may or may not
     * currently be part of that Document's actual contents.
     */
    public Document getOwnerDocument() {
        // if we have an owner simply forward the request
        // otherwise ownerNode is our ownerDocument
        if (isOwned()) {
            return ownerNode.ownerDocument();
        } else {
            return (Document) ownerNode;
        }
    }

    same as above but returns internal type and this one is not overridden
by CoreDocumentImpl to return null
/**
     * same as above but returns internal type and this one is not overridden
     * by CoreDocumentImpl to return null
     */
    CoreDocumentImpl ownerDocument() {
        // if we have an owner simply forward the request
        // otherwise ownerNode is our ownerDocument
        if (isOwned()) {
            return ownerNode.ownerDocument();
        } else {
            return (CoreDocumentImpl) ownerNode;
        }
    }

    NON-DOM
set the ownerDocument of this node
/**
     * NON-DOM
     * set the ownerDocument of this node
     */
    protected void setOwnerDocument(CoreDocumentImpl doc) {
        if (needsSyncData()) {
            synchronizeData();
        }
        // if we have an owner we rely on it to have it right
        // otherwise ownerNode is our ownerDocument
        if (!isOwned()) {
            ownerNode = doc;
        }
    }

    Returns the node number
/**
     * Returns the node number
     */
    protected int getNodeNumber() {
        int nodeNumber;
        CoreDocumentImpl cd = (CoreDocumentImpl)(this.getOwnerDocument());
        nodeNumber = cd.getNodeNumber(this);
        return nodeNumber;
    }

    Obtain the DOM-tree parent of this node, or null if it is not
currently active in the DOM tree (perhaps because it has just been
created or removed). Note that Document, DocumentFragment, and
Attribute will never have parents.
/**
     * Obtain the DOM-tree parent of this node, or null if it is not
     * currently active in the DOM tree (perhaps because it has just been
     * created or removed). Note that Document, DocumentFragment, and
     * Attribute will never have parents.
     */
    public Node getParentNode() {
        return null;            // overriden by ChildNode
    }

    /*
     * same as above but returns internal type
     */
    NodeImpl parentNode() {
        return null;
    }

    The next child of this node's parent, or null if none /** The next child of this node's parent, or null if none */
    public Node getNextSibling() {
        return null;            // default behavior, overriden in ChildNode
    }

    The previous child of this node's parent, or null if none /** The previous child of this node's parent, or null if none */
    public Node getPreviousSibling() {
        return null;            // default behavior, overriden in ChildNode
    }

    ChildNode previousSibling() {
        return null;            // default behavior, overriden in ChildNode
    }

    Return the collection of attributes associated with this node,
or null if none. At this writing, Element is the only type of node
which will ever have attributes.
See Also: ElementImpl/**
     * Return the collection of attributes associated with this node,
     * or null if none. At this writing, Element is the only type of node
     * which will ever have attributes.
     *
     * @see ElementImpl
     */
    public NamedNodeMap getAttributes() {
        return null; // overridden in ElementImpl
    }

     Returns whether this node (if it is an element) has any attributes.
See Also: ElementImpl
Returns: true if this node has any attributes,
  false otherwise.
Since: DOM Level 2/**
     *  Returns whether this node (if it is an element) has any attributes.
     * @return <code>true</code> if this node has any attributes,
     *   <code>false</code> otherwise.
     * @since DOM Level 2
     * @see ElementImpl
     */
    public boolean hasAttributes() {
        return false;           // overridden in ElementImpl
    }

    Test whether this node has any children. Convenience shorthand
for (Node.getFirstChild()!=null)

By default we do not have any children, ParentNode overrides this.
See Also: ParentNode/**
     * Test whether this node has any children. Convenience shorthand
     * for (Node.getFirstChild()!=null)
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     */
    public boolean hasChildNodes() {
        return false;
    }

    Obtain a NodeList enumerating all children of this node. If there
are none, an (initially) empty NodeList is returned.

NodeLists are "live"; as children are added/removed the NodeList
will immediately reflect those changes. Also, the NodeList refers
to the actual nodes, so changes to those nodes made via the DOM tree
will be reflected in the NodeList and vice versa.

In this implementation, Nodes implement the NodeList interface and
provide their own getChildNodes() support. Other DOMs may solve this
differently.
/**
     * Obtain a NodeList enumerating all children of this node. If there
     * are none, an (initially) empty NodeList is returned.
     * <p>
     * NodeLists are "live"; as children are added/removed the NodeList
     * will immediately reflect those changes. Also, the NodeList refers
     * to the actual nodes, so changes to those nodes made via the DOM tree
     * will be reflected in the NodeList and vice versa.
     * <p>
     * In this implementation, Nodes implement the NodeList interface and
     * provide their own getChildNodes() support. Other DOMs may solve this
     * differently.
     */
    public NodeList getChildNodes() {
        return this;
    }

    The first child of this Node, or null if none.

By default we do not have any children, ParentNode overrides this.
See Also: ParentNode/** The first child of this Node, or null if none.
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     */
    public Node getFirstChild() {
        return null;
    }

    The first child of this Node, or null if none.

By default we do not have any children, ParentNode overrides this.
See Also: ParentNode/** The first child of this Node, or null if none.
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     */
    public Node getLastChild() {
        return null;
    }

    Move one or more node(s) to our list of children. Note that this
implicitly removes them from their previous parent.

By default we do not accept any children, ParentNode overrides this.
Params: newChild – The Node to be moved to our subtree. As a
convenience feature, inserting a DocumentNode will instead insert
all its children.
refChild – Current child which newChild should be placed
immediately before. If refChild is null, the insertion occurs
after all existing Nodes, like appendChild().
Throws: DOMException – (HIERARCHY_REQUEST_ERR) if newChild is of a
type that shouldn't be a child of this node, or if newChild is an
ancestor of this node.
DOMException – (WRONG_DOCUMENT_ERR) if newChild has a
different owner document than we do.
DOMException – (NOT_FOUND_ERR) if refChild is not a child of
this node.
DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is
read-only.
See Also: ParentNode
Returns: newChild, in its new state (relocated, or emptied in the case of
DocumentNode.)/**
     * Move one or more node(s) to our list of children. Note that this
     * implicitly removes them from their previous parent.
     * <P>
     * By default we do not accept any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @param newChild The Node to be moved to our subtree. As a
     * convenience feature, inserting a DocumentNode will instead insert
     * all its children.
     *
     * @param refChild Current child which newChild should be placed
     * immediately before. If refChild is null, the insertion occurs
     * after all existing Nodes, like appendChild().
     *
     * @return newChild, in its new state (relocated, or emptied in the case of
     * DocumentNode.)
     *
     * @throws DOMException(HIERARCHY_REQUEST_ERR) if newChild is of a
     * type that shouldn't be a child of this node, or if newChild is an
     * ancestor of this node.
     *
     * @throws DOMException(WRONG_DOCUMENT_ERR) if newChild has a
     * different owner document than we do.
     *
     * @throws DOMException(NOT_FOUND_ERR) if refChild is not a child of
     * this node.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node insertBefore(Node newChild, Node refChild)
        throws DOMException {
        throw new DOMException(DOMException.HIERARCHY_REQUEST_ERR,
              DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN,
                 "HIERARCHY_REQUEST_ERR", null));
    }

    Remove a child from this Node. The removed child's subtree
remains intact so it may be re-inserted elsewhere.

By default we do not have any children, ParentNode overrides this.
Throws: DOMException – (NOT_FOUND_ERR) if oldChild is not a child of
this node.
DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is
read-only.
See Also: ParentNode
Returns: oldChild, in its new state (removed)./**
     * Remove a child from this Node. The removed child's subtree
     * remains intact so it may be re-inserted elsewhere.
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @return oldChild, in its new state (removed).
     *
     * @throws DOMException(NOT_FOUND_ERR) if oldChild is not a child of
     * this node.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node removeChild(Node oldChild)
                throws DOMException {
        throw new DOMException(DOMException.NOT_FOUND_ERR,
              DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN,
                 "NOT_FOUND_ERR", null));
    }

    Make newChild occupy the location that oldChild used to
have. Note that newChild will first be removed from its previous
parent, if any. Equivalent to inserting newChild before oldChild,
then removing oldChild.

By default we do not have any children, ParentNode overrides this.
Throws: DOMException – (HIERARCHY_REQUEST_ERR) if newChild is of a
type that shouldn't be a child of this node, or if newChild is
one of our ancestors.
DOMException – (WRONG_DOCUMENT_ERR) if newChild has a
different owner document than we do.
DOMException – (NOT_FOUND_ERR) if oldChild is not a child of
this node.
DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is
read-only.
See Also: ParentNode
Returns: oldChild, in its new state (removed)./**
     * Make newChild occupy the location that oldChild used to
     * have. Note that newChild will first be removed from its previous
     * parent, if any. Equivalent to inserting newChild before oldChild,
     * then removing oldChild.
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @return oldChild, in its new state (removed).
     *
     * @throws DOMException(HIERARCHY_REQUEST_ERR) if newChild is of a
     * type that shouldn't be a child of this node, or if newChild is
     * one of our ancestors.
     *
     * @throws DOMException(WRONG_DOCUMENT_ERR) if newChild has a
     * different owner document than we do.
     *
     * @throws DOMException(NOT_FOUND_ERR) if oldChild is not a child of
     * this node.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node replaceChild(Node newChild, Node oldChild)
        throws DOMException {
        throw new DOMException(DOMException.HIERARCHY_REQUEST_ERR,
              DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN,
                 "HIERARCHY_REQUEST_ERR", null));
    }

    //
    // NodeList methods
    //

    NodeList method: Count the immediate children of this node

By default we do not have any children, ParentNode overrides this.
See Also: ParentNode
Returns: int/**
     * NodeList method: Count the immediate children of this node
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @return int
     */
    public int getLength() {
        return 0;
    }

    NodeList method: Return the Nth immediate child of this node, or
null if the index is out of bounds.

By default we do not have any children, ParentNode overrides this.
Params: index – int
See Also: ParentNode
Returns: org.w3c.dom.Node/**
     * NodeList method: Return the Nth immediate child of this node, or
     * null if the index is out of bounds.
     * <P>
     * By default we do not have any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @return org.w3c.dom.Node
     * @param index int
     */
    public Node item(int index) {
        return null;
    }

    //
    // DOM2: methods, getters, setters
    //

    Puts all Text nodes in the full depth of the sub-tree
underneath this Node, including attribute nodes, into a
"normal" form where only markup (e.g., tags, comments, processing
instructions, CDATA sections, and entity references) separates
Text nodes, i.e., there are no adjacent Text
nodes.  This can be used to ensure that the DOM view of a document is
the same as if it were saved and re-loaded, and is useful when
operations (such as XPointer lookups) that depend on a particular
document tree structure are to be used.In cases where the document
contains CDATASections, the normalize operation alone may
not be sufficient, since XPointers do not differentiate between
Text nodes and CDATASection nodes.

Note that this implementation simply calls normalize() on this Node's
children. It is up to implementors or Node to override normalize()
to take action.
/**
     * Puts all <code>Text</code> nodes in the full depth of the sub-tree
     * underneath this <code>Node</code>, including attribute nodes, into a
     * "normal" form where only markup (e.g., tags, comments, processing
     * instructions, CDATA sections, and entity references) separates
     * <code>Text</code> nodes, i.e., there are no adjacent <code>Text</code>
     * nodes.  This can be used to ensure that the DOM view of a document is
     * the same as if it were saved and re-loaded, and is useful when
     * operations (such as XPointer lookups) that depend on a particular
     * document tree structure are to be used.In cases where the document
     * contains <code>CDATASections</code>, the normalize operation alone may
     * not be sufficient, since XPointers do not differentiate between
     * <code>Text</code> nodes and <code>CDATASection</code> nodes.
     * <p>
     * Note that this implementation simply calls normalize() on this Node's
     * children. It is up to implementors or Node to override normalize()
     * to take action.
     */
    public void normalize() {
        /* by default we do not have any children,
           ParentNode overrides this behavior */
    }

    Introduced in DOM Level 2. 
Tests whether the DOM implementation implements a specific feature and
that feature is supported by this node.
Params: feature – The package name of the feature to test. This is the same
name as what can be passed to the method hasFeature on
DOMImplementation.
version – This is the version number of the package name to
test. In Level 2, version 1, this is the string "2.0". If the version is
not specified, supporting any version of the feature will cause the
method to return true.
Returns: boolean Returns true if this node defines a subtree within which
the specified feature is supported, false otherwise.
Since: WD-DOM-Level-2-19990923/**
     * Introduced in DOM Level 2. <p>
     * Tests whether the DOM implementation implements a specific feature and
     * that feature is supported by this node.
     * @param feature The package name of the feature to test. This is the same
     * name as what can be passed to the method hasFeature on
     * DOMImplementation.
     * @param version This is the version number of the package name to
     * test. In Level 2, version 1, this is the string "2.0". If the version is
     * not specified, supporting any version of the feature will cause the
     * method to return true.
     * @return boolean Returns true if this node defines a subtree within which
     * the specified feature is supported, false otherwise.
     * @since WD-DOM-Level-2-19990923
     */
    public boolean isSupported(String feature, String version)
    {
        return ownerDocument().getImplementation().hasFeature(feature,
                                                              version);
    }

    Introduced in DOM Level 2. 
The namespace URI of this node, or null if it is unspecified. When this
node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE, this is
always null and setting it has no effect. 

This is not a computed value that is the result of a namespace lookup
based on an examination of the namespace declarations in scope. It is
merely the namespace URI given at creation time.

For nodes created with a DOM Level 1 method, such as createElement
from the Document interface, this is null.
See Also: AttrNSImpl
ElementNSImpl
Since: WD-DOM-Level-2-19990923/**
     * Introduced in DOM Level 2. <p>
     *
     * The namespace URI of this node, or null if it is unspecified. When this
     * node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE, this is
     * always null and setting it has no effect. <p>
     *
     * This is not a computed value that is the result of a namespace lookup
     * based on an examination of the namespace declarations in scope. It is
     * merely the namespace URI given at creation time.<p>
     *
     * For nodes created with a DOM Level 1 method, such as createElement
     * from the Document interface, this is null.
     * @since WD-DOM-Level-2-19990923
     * @see AttrNSImpl
     * @see ElementNSImpl
     */
    public String getNamespaceURI()
    {
        return null;
    }

    Introduced in DOM Level 2. 
The namespace prefix of this node, or null if it is unspecified. When
this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this
is always null and setting it has no effect.

For nodes created with a DOM Level 1 method, such as createElement
from the Document interface, this is null. 

See Also: AttrNSImpl
ElementNSImpl
Since: WD-DOM-Level-2-19990923/**
     * Introduced in DOM Level 2. <p>
     *
     * The namespace prefix of this node, or null if it is unspecified. When
     * this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this
     * is always null and setting it has no effect.<p>
     *
     * For nodes created with a DOM Level 1 method, such as createElement
     * from the Document interface, this is null. <p>
     *
     * @since WD-DOM-Level-2-19990923
     * @see AttrNSImpl
     * @see ElementNSImpl
     */
    public String getPrefix()
    {
        return null;
    }

     Introduced in DOM Level 2. 
 The namespace prefix of this node, or null if it is unspecified. When
 this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE
 this is always null and setting it has no effect.

 For nodes created with a DOM Level 1 method, such as createElement from
 the Document interface, this is null.

 Note that setting this attribute changes the nodeName attribute, which
 holds the qualified name, as well as the tagName and name attributes of
 the Element and Attr interfaces, when applicable.

Throws: INVALID_CHARACTER_ERR – Raised if the specified
 prefix contains an invalid character.
See Also: AttrNSImpl
ElementNSImpl
Since: WD-DOM-Level-2-19990923/**
     *  Introduced in DOM Level 2. <p>
     *
     *  The namespace prefix of this node, or null if it is unspecified. When
     *  this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE
     *  this is always null and setting it has no effect.<p>
     *
     *  For nodes created with a DOM Level 1 method, such as createElement from
     *  the Document interface, this is null.<p>
     *
     *  Note that setting this attribute changes the nodeName attribute, which
     *  holds the qualified name, as well as the tagName and name attributes of
     *  the Element and Attr interfaces, when applicable.<p>
     *
     * @throws INVALID_CHARACTER_ERR Raised if the specified
     *  prefix contains an invalid character.
     *
     * @since WD-DOM-Level-2-19990923
     * @see AttrNSImpl
     * @see ElementNSImpl
     */
    public void setPrefix(String prefix)
        throws DOMException
    {
        throw new DOMException(DOMException.NAMESPACE_ERR,
              DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN,
                 "NAMESPACE_ERR", null));
    }

    Introduced in DOM Level 2. 
Returns the local part of the qualified name of this node.
For nodes created with a DOM Level 1 method, such as createElement
from the Document interface, and for nodes of any type other than
ELEMENT_NODE and ATTRIBUTE_NODE this is the same as the nodeName
attribute.
See Also: AttrNSImpl
ElementNSImpl
Since: WD-DOM-Level-2-19990923/**
     * Introduced in DOM Level 2. <p>
     *
     * Returns the local part of the qualified name of this node.
     * For nodes created with a DOM Level 1 method, such as createElement
     * from the Document interface, and for nodes of any type other than
     * ELEMENT_NODE and ATTRIBUTE_NODE this is the same as the nodeName
     * attribute.
     * @since WD-DOM-Level-2-19990923
     * @see AttrNSImpl
     * @see ElementNSImpl
     */
    public String             getLocalName()
    {
        return null;
    }

    //
    // EventTarget support
    //

    public void addEventListener(String type, EventListener listener,
                                 boolean useCapture) {
        // simply forward to Document
        ownerDocument().addEventListener(this, type, listener, useCapture);
    }

    public void removeEventListener(String type, EventListener listener,
                                    boolean useCapture) {
        // simply forward to Document
        ownerDocument().removeEventListener(this, type, listener, useCapture);
    }

    public boolean dispatchEvent(Event event) {
        // simply forward to Document
        return ownerDocument().dispatchEvent(this, event);
    }

    //
    // Public DOM Level 3 methods
    //

    The absolute base URI of this node or null if undefined.
This value is computed according to . However, when the
Document supports the feature "HTML" , the base URI is
computed using first the value of the href attribute of the HTML BASE
element if any, and the value of the documentURI
attribute from the Document interface otherwise.

 When the node is an Element, a Document
or a a ProcessingInstruction, this attribute represents
the properties [base URI] defined in . When the node is a
Notation, an Entity, or an
EntityReference, this attribute represents the
properties [declaration base URI] in the . How will this be affected
by resolution of relative namespace URIs issue?It's not.Should this
only be on Document, Element, ProcessingInstruction, Entity, and
Notation nodes, according to the infoset? If not, what is it equal to
on other nodes? Null? An empty string? I think it should be the
parent's.No.Should this be read-only and computed or and actual
read-write attribute?Read-only and computed (F2F 19 Jun 2000 and
teleconference 30 May 2001).If the base HTML element is not yet
attached to a document, does the insert change the Document.baseURI?
Yes. (F2F 26 Sep 2001)
Since: DOM Level 3/**
     * The absolute base URI of this node or <code>null</code> if undefined.
     * This value is computed according to . However, when the
     * <code>Document</code> supports the feature "HTML" , the base URI is
     * computed using first the value of the href attribute of the HTML BASE
     * element if any, and the value of the <code>documentURI</code>
     * attribute from the <code>Document</code> interface otherwise.
     * <br> When the node is an <code>Element</code>, a <code>Document</code>
     * or a a <code>ProcessingInstruction</code>, this attribute represents
     * the properties [base URI] defined in . When the node is a
     * <code>Notation</code>, an <code>Entity</code>, or an
     * <code>EntityReference</code>, this attribute represents the
     * properties [declaration base URI] in the . How will this be affected
     * by resolution of relative namespace URIs issue?It's not.Should this
     * only be on Document, Element, ProcessingInstruction, Entity, and
     * Notation nodes, according to the infoset? If not, what is it equal to
     * on other nodes? Null? An empty string? I think it should be the
     * parent's.No.Should this be read-only and computed or and actual
     * read-write attribute?Read-only and computed (F2F 19 Jun 2000 and
     * teleconference 30 May 2001).If the base HTML element is not yet
     * attached to a document, does the insert change the Document.baseURI?
     * Yes. (F2F 26 Sep 2001)
     * @since DOM Level 3
     */
    public String getBaseURI() {
        return null;
    }

    Compares a node with this node with regard to their position in the
tree and according to the document order. This order can be extended
by module that define additional types of nodes.
Params: other – The node to compare against this node.
Returns: Returns how the given node is positioned relatively to this
  node.
Since: DOM Level 3
Deprecated: /**
     * Compares a node with this node with regard to their position in the
     * tree and according to the document order. This order can be extended
     * by module that define additional types of nodes.
     * @param other The node to compare against this node.
     * @return Returns how the given node is positioned relatively to this
     *   node.
     * @since DOM Level 3
     * @deprecated
     */
    @Deprecated
    public short compareTreePosition(Node other) {
        // Questions of clarification for this method - to be answered by the
        // DOM WG.   Current assumptions listed - LM
        //
        // 1. How do ENTITY nodes compare?
        //    Current assumption: TREE_POSITION_DISCONNECTED, as ENTITY nodes
        //    aren't really 'in the tree'
        //
        // 2. How do NOTATION nodes compare?
        //    Current assumption: TREE_POSITION_DISCONNECTED, as NOTATION nodes
        //    aren't really 'in the tree'
        //
        // 3. Are TREE_POSITION_ANCESTOR and TREE_POSITION_DESCENDANT
        //    only relevant for nodes that are "part of the document tree"?
        //     <outer>
        //         <inner  myattr="true"/>
        //     </outer>
        //    Is the element node "outer" considered an ancestor of "myattr"?
        //    Current assumption: No.
        //
        // 4. How do children of ATTRIBUTE nodes compare (with eachother, or
        //    with children of other attribute nodes with the same element)
        //    Current assumption: Children of ATTRIBUTE nodes are treated as if
        //    they they are the attribute node itself, unless the 2 nodes
        //    are both children of the same attribute.
        //
        // 5. How does an ENTITY_REFERENCE node compare with it's children?
        //    Given the DOM, it should precede its children as an ancestor.
        //    Given "document order",  does it represent the same position?
        //    Current assumption: An ENTITY_REFERENCE node is an ancestor of its
        //    children.
        //
        // 6. How do children of a DocumentFragment compare?
        //    Current assumption: If both nodes are part of the same document
        //    fragment, there are compared as if they were part of a document.


        // If the nodes are the same...
        if (this==other)
          return (TREE_POSITION_SAME_NODE | TREE_POSITION_EQUIVALENT);

        // If either node is of type ENTITY or NOTATION, compare as disconnected
        short thisType = this.getNodeType();
        short otherType = other.getNodeType();

        // If either node is of type ENTITY or NOTATION, compare as disconnected
        if (thisType == Node.ENTITY_NODE ||
            thisType == Node.NOTATION_NODE ||
            otherType == Node.ENTITY_NODE ||
            otherType == Node.NOTATION_NODE ) {
          return TREE_POSITION_DISCONNECTED;
        }

        // Find the ancestor of each node, and the distance each node is from
        // its ancestor.
        // During this traversal, look for ancestor/descendent relationships
        // between the 2 nodes in question.
        // We do this now, so that we get this info correct for attribute nodes
        // and their children.

        Node node;
        Node thisAncestor = this;
        Node otherAncestor = other;
        int thisDepth=0;
        int otherDepth=0;
        for (node=this; node != null; node = node.getParentNode()) {
            thisDepth +=1;
            if (node == other)
              // The other node is an ancestor of this one.
              return (TREE_POSITION_ANCESTOR | TREE_POSITION_PRECEDING);
            thisAncestor = node;
        }

        for (node=other; node!=null; node=node.getParentNode()) {
            otherDepth +=1;
            if (node == this)
              // The other node is a descendent of the reference node.
              return (TREE_POSITION_DESCENDANT | TREE_POSITION_FOLLOWING);
            otherAncestor = node;
        }


        Node thisNode = this;
        Node otherNode = other;

        int thisAncestorType = thisAncestor.getNodeType();
        int otherAncestorType = otherAncestor.getNodeType();

        // if the ancestor is an attribute, get owning element.
        // we are now interested in the owner to determine position.

        if (thisAncestorType == Node.ATTRIBUTE_NODE)  {
           thisNode = ((AttrImpl)thisAncestor).getOwnerElement();
        }
        if (otherAncestorType == Node.ATTRIBUTE_NODE) {
           otherNode = ((AttrImpl)otherAncestor).getOwnerElement();
        }

        // Before proceeding, we should check if both ancestor nodes turned
        // out to be attributes for the same element
        if (thisAncestorType == Node.ATTRIBUTE_NODE &&
            otherAncestorType == Node.ATTRIBUTE_NODE &&
            thisNode==otherNode)
            return TREE_POSITION_EQUIVALENT;

        // Now, find the ancestor of the owning element, if the original
        // ancestor was an attribute

        // Note:  the following 2 loops are quite close to the ones above.
        // May want to common them up.  LM.
        if (thisAncestorType == Node.ATTRIBUTE_NODE) {
            thisDepth=0;
            for (node=thisNode; node != null; node=node.getParentNode()) {
                thisDepth +=1;
                if (node == otherNode)
                  // The other node is an ancestor of the owning element
                  {
                  return TREE_POSITION_PRECEDING;
                  }
                thisAncestor = node;
            }
        }

        // Now, find the ancestor of the owning element, if the original
        // ancestor was an attribute
        if (otherAncestorType == Node.ATTRIBUTE_NODE) {
            otherDepth=0;
            for (node=otherNode; node != null; node=node.getParentNode()) {
                otherDepth +=1;
                if (node == thisNode)
                  // The other node is a descendent of the reference
                  // node's element
                  return TREE_POSITION_FOLLOWING;
                otherAncestor = node;
            }
        }

        // thisAncestor and otherAncestor must be the same at this point,
        // otherwise, we are not in the same tree or document fragment
        if (thisAncestor != otherAncestor)
          return TREE_POSITION_DISCONNECTED;


        // Go up the parent chain of the deeper node, until we find a node
        // with the same depth as the shallower node

        if (thisDepth > otherDepth) {
          for (int i=0; i<thisDepth - otherDepth; i++)
            thisNode = thisNode.getParentNode();
          // Check if the node we have reached is in fact "otherNode". This can
          // happen in the case of attributes.  In this case, otherNode
          // "precedes" this.
          if (thisNode == otherNode)
            return TREE_POSITION_PRECEDING;
        }

        else {
          for (int i=0; i<otherDepth - thisDepth; i++)
            otherNode = otherNode.getParentNode();
          // Check if the node we have reached is in fact "thisNode".  This can
          // happen in the case of attributes.  In this case, otherNode
          // "follows" this.
          if (otherNode == thisNode)
            return TREE_POSITION_FOLLOWING;
        }

        // We now have nodes at the same depth in the tree.  Find a common
        // ancestor.
        Node thisNodeP, otherNodeP;
        for (thisNodeP=thisNode.getParentNode(),
                  otherNodeP=otherNode.getParentNode();
             thisNodeP!=otherNodeP;) {
             thisNode = thisNodeP;
             otherNode = otherNodeP;
             thisNodeP = thisNodeP.getParentNode();
             otherNodeP = otherNodeP.getParentNode();
        }

        // At this point, thisNode and otherNode are direct children of
        // the common ancestor.
        // See whether thisNode or otherNode is the leftmost

        for (Node current=thisNodeP.getFirstChild();
                  current!=null;
                  current=current.getNextSibling()) {
               if (current==otherNode) {
                 return TREE_POSITION_PRECEDING;
               }
               else if (current==thisNode) {
                 return TREE_POSITION_FOLLOWING;
               }
        }
        // REVISIT:  shouldn't get here.   Should probably throw an
        // exception
        return 0;

    }
    Compares a node with this node with regard to their position in the
document.
Params: other – The node to compare against this node.
Returns: Returns how the given node is positioned relatively to this
  node.
Since: DOM Level 3/**
     * Compares a node with this node with regard to their position in the
     * document.
     * @param other The node to compare against this node.
     * @return Returns how the given node is positioned relatively to this
     *   node.
     * @since DOM Level 3
     */
    public short compareDocumentPosition(Node other) throws DOMException {

        // If the nodes are the same, no flags should be set
        if (this==other)
          return 0;

        // check if other is from a different implementation
        if (other != null && !(other instanceof NodeImpl)) {
            // other comes from a different implementation
            String msg = DOMMessageFormatter.formatMessage(
               DOMMessageFormatter.DOM_DOMAIN, "NOT_SUPPORTED_ERR", null);
            throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
        }

        Document thisOwnerDoc, otherOwnerDoc;
        // get the respective Document owners.
        if (this.getNodeType() == Node.DOCUMENT_NODE)
          thisOwnerDoc = (Document)this;
        else
          thisOwnerDoc = this.getOwnerDocument();
        if (other.getNodeType() == Node.DOCUMENT_NODE)
          otherOwnerDoc = (Document)other;
        else
          otherOwnerDoc = other.getOwnerDocument();

        // If from different documents, we know they are disconnected.
        // and have an implementation dependent order
        if (thisOwnerDoc != otherOwnerDoc &&
            thisOwnerDoc !=null &&
            otherOwnerDoc !=null)
 {
          int otherDocNum = ((CoreDocumentImpl)otherOwnerDoc).getNodeNumber();
          int thisDocNum = ((CoreDocumentImpl)thisOwnerDoc).getNodeNumber();
          if (otherDocNum > thisDocNum)
            return DOCUMENT_POSITION_DISCONNECTED |
                   DOCUMENT_POSITION_FOLLOWING |
                   DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC;
          else
            return DOCUMENT_POSITION_DISCONNECTED |
                   DOCUMENT_POSITION_PRECEDING |
                   DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC;

        }

        // Find the ancestor of each node, and the distance each node is from
        // its ancestor.
        // During this traversal, look for ancestor/descendent relationships
        // between the 2 nodes in question.
        // We do this now, so that we get this info correct for attribute nodes
        // and their children.

        Node node;
        Node thisAncestor = this;
        Node otherAncestor = other;

        int thisDepth=0;
        int otherDepth=0;
        for (node=this; node != null; node = node.getParentNode()) {
            thisDepth +=1;
            if (node == other)
              // The other node is an ancestor of this one.
              return (DOCUMENT_POSITION_CONTAINS |
                      DOCUMENT_POSITION_PRECEDING);
            thisAncestor = node;
        }

        for (node=other; node!=null; node=node.getParentNode()) {
            otherDepth +=1;
            if (node == this)
              // The other node is a descendent of the reference node.
              return (DOCUMENT_POSITION_CONTAINED_BY |
                      DOCUMENT_POSITION_FOLLOWING);
            otherAncestor = node;
        }



        int thisAncestorType = thisAncestor.getNodeType();
        int otherAncestorType = otherAncestor.getNodeType();
        Node thisNode = this;
        Node otherNode = other;

        // Special casing for ENTITY, NOTATION, DOCTYPE and ATTRIBUTES
        // LM:  should rewrite this.
        switch (thisAncestorType) {
          case Node.NOTATION_NODE:
          case Node.ENTITY_NODE: {
            DocumentType container = thisOwnerDoc.getDoctype();
            if (container == otherAncestor) return
                   (DOCUMENT_POSITION_CONTAINS | DOCUMENT_POSITION_PRECEDING);
            switch (otherAncestorType) {
              case Node.NOTATION_NODE:
              case Node.ENTITY_NODE:  {
                if (thisAncestorType != otherAncestorType)
                 // the nodes are of different types
                 return ((thisAncestorType>otherAncestorType) ?
                    DOCUMENT_POSITION_PRECEDING:DOCUMENT_POSITION_FOLLOWING);
                else {
                 // the nodes are of the same type.  Find order.
                 if (thisAncestorType == Node.NOTATION_NODE)

                     if (((NamedNodeMapImpl)container.getNotations()).precedes(otherAncestor,thisAncestor))
                       return (DOCUMENT_POSITION_PRECEDING |
                               DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
                     else
                       return (DOCUMENT_POSITION_FOLLOWING |
                               DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
                 else
                     if (((NamedNodeMapImpl)container.getEntities()).precedes(otherAncestor,thisAncestor))
                       return (DOCUMENT_POSITION_PRECEDING |
                               DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
                     else
                       return (DOCUMENT_POSITION_FOLLOWING |
                               DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
                }
              }
            }
            thisNode = thisAncestor = thisOwnerDoc;
            break;
          }
          case Node.DOCUMENT_TYPE_NODE: {
            if (otherNode == thisOwnerDoc)
              return (DOCUMENT_POSITION_PRECEDING |
                      DOCUMENT_POSITION_CONTAINS);
            else if (thisOwnerDoc!=null && thisOwnerDoc==otherOwnerDoc)
              return (DOCUMENT_POSITION_FOLLOWING);
            break;
          }
          case Node.ATTRIBUTE_NODE: {
            thisNode = ((AttrImpl)thisAncestor).getOwnerElement();
            if (otherAncestorType==Node.ATTRIBUTE_NODE) {
              otherNode = ((AttrImpl)otherAncestor).getOwnerElement();
              if (otherNode == thisNode) {
                if (((NamedNodeMapImpl)thisNode.getAttributes()).precedes(other,this))
                  return (DOCUMENT_POSITION_PRECEDING |
                          DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
                else
                  return (DOCUMENT_POSITION_FOLLOWING |
                          DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
              }
            }

            // Now, find the ancestor of the element
            thisDepth=0;
            for (node=thisNode; node != null; node=node.getParentNode()) {
                thisDepth +=1;
                if (node == otherNode)
                  {
                  // The other node is an ancestor of the owning element
                  return (DOCUMENT_POSITION_CONTAINS |
                          DOCUMENT_POSITION_PRECEDING);
                  }
                thisAncestor = node;
            }
          }
        }
        switch (otherAncestorType) {
          case Node.NOTATION_NODE:
          case Node.ENTITY_NODE: {
          DocumentType container = thisOwnerDoc.getDoctype();
            if (container == this) return (DOCUMENT_POSITION_CONTAINED_BY |
                                          DOCUMENT_POSITION_FOLLOWING);
            otherNode = otherAncestor = thisOwnerDoc;
            break;
          }
          case Node.DOCUMENT_TYPE_NODE: {
            if (thisNode == otherOwnerDoc)
              return (DOCUMENT_POSITION_FOLLOWING |
                      DOCUMENT_POSITION_CONTAINED_BY);
            else if (otherOwnerDoc!=null && thisOwnerDoc==otherOwnerDoc)
              return (DOCUMENT_POSITION_PRECEDING);
            break;
          }
          case Node.ATTRIBUTE_NODE: {
            otherDepth=0;
            otherNode = ((AttrImpl)otherAncestor).getOwnerElement();
            for (node=otherNode; node != null; node=node.getParentNode()) {
                otherDepth +=1;
                if (node == thisNode)
                  // The other node is a descendent of the reference
                  // node's element
                  return DOCUMENT_POSITION_FOLLOWING |
                         DOCUMENT_POSITION_CONTAINED_BY;
                otherAncestor = node;
            }

          }
        }

        // thisAncestor and otherAncestor must be the same at this point,
        // otherwise, the original nodes are disconnected
        if (thisAncestor != otherAncestor) {
          int thisAncestorNum, otherAncestorNum;
          thisAncestorNum = ((NodeImpl)thisAncestor).getNodeNumber();
          otherAncestorNum = ((NodeImpl)otherAncestor).getNodeNumber();

          if (thisAncestorNum > otherAncestorNum)
            return DOCUMENT_POSITION_DISCONNECTED |
                   DOCUMENT_POSITION_FOLLOWING |
                   DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC;
          else
            return DOCUMENT_POSITION_DISCONNECTED |
                   DOCUMENT_POSITION_PRECEDING |
                   DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC;
        }


        // Go up the parent chain of the deeper node, until we find a node
        // with the same depth as the shallower node

        if (thisDepth > otherDepth) {
          for (int i=0; i<thisDepth - otherDepth; i++)
            thisNode = thisNode.getParentNode();
          // Check if the node we have reached is in fact "otherNode". This can
          // happen in the case of attributes.  In this case, otherNode
          // "precedes" this.
          if (thisNode == otherNode)
{
            return DOCUMENT_POSITION_PRECEDING;
          }
        }

        else {
          for (int i=0; i<otherDepth - thisDepth; i++)
            otherNode = otherNode.getParentNode();
          // Check if the node we have reached is in fact "thisNode".  This can
          // happen in the case of attributes.  In this case, otherNode
          // "follows" this.
          if (otherNode == thisNode)
            return DOCUMENT_POSITION_FOLLOWING;
        }

        // We now have nodes at the same depth in the tree.  Find a common
        // ancestor.
        Node thisNodeP, otherNodeP;
        for (thisNodeP=thisNode.getParentNode(),
                  otherNodeP=otherNode.getParentNode();
             thisNodeP!=otherNodeP;) {
             thisNode = thisNodeP;
             otherNode = otherNodeP;
             thisNodeP = thisNodeP.getParentNode();
             otherNodeP = otherNodeP.getParentNode();
        }

        // At this point, thisNode and otherNode are direct children of
        // the common ancestor.
        // See whether thisNode or otherNode is the leftmost

        for (Node current=thisNodeP.getFirstChild();
                  current!=null;
                  current=current.getNextSibling()) {
               if (current==otherNode) {
                 return DOCUMENT_POSITION_PRECEDING;
               }
               else if (current==thisNode) {
                 return DOCUMENT_POSITION_FOLLOWING;
               }
        }
        // REVISIT:  shouldn't get here.   Should probably throw an
        // exception
        return 0;

    }

    This attribute returns the text content of this node and its
descendants. When it is defined to be null, setting it has no effect.
When set, any possible children this node may have are removed and
replaced by a single Text node containing the string
this attribute is set to. On getting, no serialization is performed,
the returned string does not contain any markup. No whitespace
normalization is performed, the returned string does not contain the
element content whitespaces . Similarly, on setting, no parsing is
performed either, the input string is taken as pure textual content.

The string returned is made of the text content of this node
depending on its type, as defined below:
Text

/**
This attribute returns the text content of this node and its
descendants. When it is defined to be null, setting it has no effect.
When set, any possible children this node may have are removed and
replaced by a single  node containing the string
this attribute is set to. On getting, no serialization is performed,
the returned string does not contain any markup. No whitespace
normalization is performed, the returned string does not contain the
element content whitespaces . Similarly, on setting, no parsing is
performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node
depending on its type, as defined below:


Node type
Content


Node type
Content



ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE,
DOCUMENT_FRAGMENT_NODE
concatenation of the textContent
attribute value of every child node, excluding COMMENT_NODE and
PROCESSING_INSTRUCTION_NODE nodes


ATTRIBUTE_NODE, TEXT_NODE,
CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE

nodeValue


DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE

null


Throws: DOMException – 
  NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
DOMException – 
  DOMSTRING_SIZE_ERR: Raised when it would return more characters than
  fit in a DOMString variable on the implementation
  platform.
Since: DOM Level 3/**
     * This attribute returns the text content of this node and its
     * descendants. When it is defined to be null, setting it has no effect.
     * When set, any possible children this node may have are removed and
     * replaced by a single <code>Text</code> node containing the string
     * this attribute is set to. On getting, no serialization is performed,
     * the returned string does not contain any markup. No whitespace
     * normalization is performed, the returned string does not contain the
     * element content whitespaces . Similarly, on setting, no parsing is
     * performed either, the input string is taken as pure textual content.
     * <br>The string returned is made of the text content of this node
     * depending on its type, as defined below:
     * <table border='1'>
     * <tr>
     * <th>Node type</th>
     * <th>Content</th>
     * </tr>

    /**
     * This attribute returns the text content of this node and its
     * descendants. When it is defined to be null, setting it has no effect.
     * When set, any possible children this node may have are removed and
     * replaced by a single <code>Text</code> node containing the string
     * this attribute is set to. On getting, no serialization is performed,
     * the returned string does not contain any markup. No whitespace
     * normalization is performed, the returned string does not contain the
     * element content whitespaces . Similarly, on setting, no parsing is
     * performed either, the input string is taken as pure textual content.
     * <br>The string returned is made of the text content of this node
     * depending on its type, as defined below:
     * <table border='1'>
     * <tr>
     * <th>Node type</th>
     * <th>Content</th>
     * </tr>
     * <tr>
     * <td valign='top' rowspan='1' colspan='1'>
     * ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE,
     * DOCUMENT_FRAGMENT_NODE</td>
     * <td valign='top' rowspan='1' colspan='1'>concatenation of the <code>textContent</code>
     * attribute value of every child node, excluding COMMENT_NODE and
     * PROCESSING_INSTRUCTION_NODE nodes</td>
     * </tr>
     * <tr>
     * <td valign='top' rowspan='1' colspan='1'>ATTRIBUTE_NODE, TEXT_NODE,
     * CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE</td>
     * <td valign='top' rowspan='1' colspan='1'>
     * <code>nodeValue</code></td>
     * </tr>
     * <tr>
     * <td valign='top' rowspan='1' colspan='1'>DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE</td>
     * <td valign='top' rowspan='1' colspan='1'>
     * null</td>
     * </tr>
     * </table>
     * @exception DOMException
     *   NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
     * @exception DOMException
     *   DOMSTRING_SIZE_ERR: Raised when it would return more characters than
     *   fit in a <code>DOMString</code> variable on the implementation
     *   platform.
     * @since DOM Level 3
     */
    public String getTextContent() throws DOMException {
        return getNodeValue();  // overriden in some subclasses
    }

    // internal method taking a StringBuilder in parameter
    void getTextContent(StringBuilder buf) throws DOMException {
        String content = getNodeValue();
        if (content != null) {
            buf.append(content);
        }
    }

    This attribute returns the text content of this node and its
descendants. When it is defined to be null, setting it has no effect.
When set, any possible children this node may have are removed and
replaced by a single Text node containing the string
this attribute is set to. On getting, no serialization is performed,
the returned string does not contain any markup. No whitespace
normalization is performed, the returned string does not contain the
element content whitespaces . Similarly, on setting, no parsing is
performed either, the input string is taken as pure textual content.

The string returned is made of the text content of this node
depending on its type, as defined below:


Node type
Content



ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE,
DOCUMENT_FRAGMENT_NODE
concatenation of the textContent
attribute value of every child node, excluding COMMENT_NODE and
PROCESSING_INSTRUCTION_NODE nodes


ATTRIBUTE_NODE, TEXT_NODE,
CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE

nodeValue


DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE

null


Throws: DOMException – 
  NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
DOMException – 
  DOMSTRING_SIZE_ERR: Raised when it would return more characters than
  fit in a DOMString variable on the implementation
  platform.
Since: DOM Level 3/**
     * This attribute returns the text content of this node and its
     * descendants. When it is defined to be null, setting it has no effect.
     * When set, any possible children this node may have are removed and
     * replaced by a single <code>Text</code> node containing the string
     * this attribute is set to. On getting, no serialization is performed,
     * the returned string does not contain any markup. No whitespace
     * normalization is performed, the returned string does not contain the
     * element content whitespaces . Similarly, on setting, no parsing is
     * performed either, the input string is taken as pure textual content.
     * <br>The string returned is made of the text content of this node
     * depending on its type, as defined below:
     * <table border='1'>
     * <tr>
     * <th>Node type</th>
     * <th>Content</th>
     * </tr>
     * <tr>
     * <td valign='top' rowspan='1' colspan='1'>
     * ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE,
     * DOCUMENT_FRAGMENT_NODE</td>
     * <td valign='top' rowspan='1' colspan='1'>concatenation of the <code>textContent</code>
     * attribute value of every child node, excluding COMMENT_NODE and
     * PROCESSING_INSTRUCTION_NODE nodes</td>
     * </tr>
     * <tr>
     * <td valign='top' rowspan='1' colspan='1'>ATTRIBUTE_NODE, TEXT_NODE,
     * CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE</td>
     * <td valign='top' rowspan='1' colspan='1'>
     * <code>nodeValue</code></td>
     * </tr>
     * <tr>
     * <td valign='top' rowspan='1' colspan='1'>DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE</td>
     * <td valign='top' rowspan='1' colspan='1'>
     * null</td>
     * </tr>
     * </table>
     * @exception DOMException
     *   NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
     * @exception DOMException
     *   DOMSTRING_SIZE_ERR: Raised when it would return more characters than
     *   fit in a <code>DOMString</code> variable on the implementation
     *   platform.
     * @since DOM Level 3
     */
    public void setTextContent(String textContent)
        throws DOMException {
        setNodeValue(textContent);
    }

    Returns whether this node is the same node as the given one.

This method provides a way to determine whether two
Node references returned by the implementation reference
the same object. When two Node references are references
to the same object, even if through a proxy, the references may be
used completely interchangably, such that all attributes have the
same values and calling the same DOM method on either reference
always has exactly the same effect.
Params: other – The node to test against.
Returns: Returns true if the nodes are the same,
  false otherwise.
Since: DOM Level 3/**
     * Returns whether this node is the same node as the given one.
     * <br>This method provides a way to determine whether two
     * <code>Node</code> references returned by the implementation reference
     * the same object. When two <code>Node</code> references are references
     * to the same object, even if through a proxy, the references may be
     * used completely interchangably, such that all attributes have the
     * same values and calling the same DOM method on either reference
     * always has exactly the same effect.
     * @param other The node to test against.
     * @return Returns <code>true</code> if the nodes are the same,
     *   <code>false</code> otherwise.
     * @since DOM Level 3
     */
    public boolean isSameNode(Node other) {
        // we do not use any wrapper so the answer is obvious
        return this == other;
    }




     DOM Level 3: Experimental
 This method checks if the specified namespaceURI is the
 default namespace or not.
 @param namespaceURI The namespace URI to look for.
 @return  true if the specified namespaceURI
  is the default namespace, false otherwise.
Since: DOM Level 3/**
     *  DOM Level 3: Experimental
     *  This method checks if the specified <code>namespaceURI</code> is the
     *  default namespace or not.
     *  @param namespaceURI The namespace URI to look for.
     *  @return  <code>true</code> if the specified <code>namespaceURI</code>
     *   is the default namespace, <code>false</code> otherwise.
     * @since DOM Level 3
     */
    public boolean isDefaultNamespace(String namespaceURI){
        // REVISIT: remove casts when DOM L3 becomes REC.
        short type = this.getNodeType();
        switch (type) {
        case Node.ELEMENT_NODE: {
            String namespace = this.getNamespaceURI();
            String prefix = this.getPrefix();

            // REVISIT: is it possible that prefix is empty string?
            if (prefix == null || prefix.length() == 0) {
                if (namespaceURI == null) {
                    return (namespace == namespaceURI);
                }
                return namespaceURI.equals(namespace);
            }
            if (this.hasAttributes()) {
                ElementImpl elem = (ElementImpl)this;
                NodeImpl attr = (NodeImpl)elem.getAttributeNodeNS("http://www.w3.org/2000/xmlns/", "xmlns");
                if (attr != null) {
                    String value = attr.getNodeValue();
                    if (namespaceURI == null) {
                        return (namespace == value);
                    }
                    return namespaceURI.equals(value);
                }
            }

            NodeImpl ancestor = (NodeImpl)getElementAncestor(this);
            if (ancestor != null) {
                return ancestor.isDefaultNamespace(namespaceURI);
            }
            return false;
        }
        case Node.DOCUMENT_NODE:{
                Element docElement = ((Document)this).getDocumentElement();
                if (docElement != null) {
                    return docElement.isDefaultNamespace(namespaceURI);
                }
                return false;
            }

        case Node.ENTITY_NODE :
        case Node.NOTATION_NODE:
        case Node.DOCUMENT_FRAGMENT_NODE:
        case Node.DOCUMENT_TYPE_NODE:
            // type is unknown
            return false;
        case Node.ATTRIBUTE_NODE:{
                if (this.ownerNode.getNodeType() == Node.ELEMENT_NODE) {
                    return ownerNode.isDefaultNamespace(namespaceURI);

                }
                return false;
            }
        default:{
                NodeImpl ancestor = (NodeImpl)getElementAncestor(this);
                if (ancestor != null) {
                    return ancestor.isDefaultNamespace(namespaceURI);
                }
                return false;
            }

        }


    }


    DOM Level 3 - Experimental:
Look up the prefix associated to the given namespace URI, starting from this node.
Params: namespaceURI – 
Returns: the prefix for the namespace/**
     *
     * DOM Level 3 - Experimental:
     * Look up the prefix associated to the given namespace URI, starting from this node.
     *
     * @param namespaceURI
     * @return the prefix for the namespace
     */
    public String lookupPrefix(String namespaceURI){

        // REVISIT: When Namespaces 1.1 comes out this may not be true
        // Prefix can't be bound to null namespace
        if (namespaceURI == null) {
            return null;
        }

        short type = this.getNodeType();

        switch (type) {
        case Node.ELEMENT_NODE: {
                this.getNamespaceURI(); // to flip out children
                return lookupNamespacePrefix(namespaceURI, (ElementImpl)this);
            }
        case Node.DOCUMENT_NODE:{
                Element docElement = ((Document)this).getDocumentElement();
                if (docElement != null) {
                    return docElement.lookupPrefix(namespaceURI);
                }
                return null;
            }

        case Node.ENTITY_NODE :
        case Node.NOTATION_NODE:
        case Node.DOCUMENT_FRAGMENT_NODE:
        case Node.DOCUMENT_TYPE_NODE:
            // type is unknown
            return null;
        case Node.ATTRIBUTE_NODE:{
                if (this.ownerNode.getNodeType() == Node.ELEMENT_NODE) {
                    return ownerNode.lookupPrefix(namespaceURI);

                }
                return null;
            }
        default:{
                NodeImpl ancestor = (NodeImpl)getElementAncestor(this);
                if (ancestor != null) {
                    return ancestor.lookupPrefix(namespaceURI);
                }
                return null;
            }

        }
    }
    DOM Level 3 - Experimental:
Look up the namespace URI associated to the given prefix, starting from this node.
Use lookupNamespaceURI(null) to lookup the default namespace
Params: specifiedPrefix – 
Returns: the URI for the namespace
Since: DOM Level 3/**
     * DOM Level 3 - Experimental:
     * Look up the namespace URI associated to the given prefix, starting from this node.
     * Use lookupNamespaceURI(null) to lookup the default namespace
     *
     * @param specifiedPrefix
     * @return the URI for the namespace
     * @since DOM Level 3
     */
    public String lookupNamespaceURI(String specifiedPrefix) {
        short type = this.getNodeType();
        switch (type) {
        case Node.ELEMENT_NODE : {

                String namespace = this.getNamespaceURI();
                String prefix = this.getPrefix();
                if (namespace !=null) {
                    // REVISIT: is it possible that prefix is empty string?
                    if (specifiedPrefix== null && prefix==specifiedPrefix) {
                        // looking for default namespace
                        return namespace;
                    } else if (prefix != null && prefix.equals(specifiedPrefix)) {
                        // non default namespace
                        return namespace;
                    }
                }
                if (this.hasAttributes()) {
                    NamedNodeMap map = this.getAttributes();
                    int length = map.getLength();
                    for (int i=0;i<length;i++) {
                        Node attr = map.item(i);
                        namespace = attr.getNamespaceURI();
                        if (namespace !=null && namespace.equals("http://www.w3.org/2000/xmlns/")) {
                            String attrPrefix = attr.getPrefix();
                            String value = attr.getNodeValue();
                            // at this point we are dealing with DOM Level 2 nodes only
                            if (specifiedPrefix == null &&
                                attr.getNodeName().equals("xmlns")) {
                                // default namespace
                                return value.length() > 0 ? value : null;
                            } else if (attrPrefix !=null &&
                                       attrPrefix.equals("xmlns") &&
                                       attr.getLocalName().equals(specifiedPrefix)) {
                                // non default namespace
                                return value.length() > 0 ? value : null;
                            }
                        }
                    }
                }
                NodeImpl ancestor = (NodeImpl)getElementAncestor(this);
                if (ancestor != null) {
                    return ancestor.lookupNamespaceURI(specifiedPrefix);
                }

                return null;


            }
        case Node.DOCUMENT_NODE : {
                Element docElement = ((Document)this).getDocumentElement();
                if (docElement != null) {
                    return docElement.lookupNamespaceURI(specifiedPrefix);
                }
                return null;
            }
        case Node.ENTITY_NODE :
        case Node.NOTATION_NODE:
        case Node.DOCUMENT_FRAGMENT_NODE:
        case Node.DOCUMENT_TYPE_NODE:
            // type is unknown
            return null;
        case Node.ATTRIBUTE_NODE:{
                if (this.ownerNode.getNodeType() == Node.ELEMENT_NODE) {
                    return ownerNode.lookupNamespaceURI(specifiedPrefix);

                }
                return null;
            }
        default:{
                NodeImpl ancestor = (NodeImpl)getElementAncestor(this);
                if (ancestor != null) {
                    return ancestor.lookupNamespaceURI(specifiedPrefix);
                }
                return null;
            }

        }
    }

    Node getElementAncestor(Node currentNode) {
        Node parent = currentNode.getParentNode();
        while (parent != null) {
            short type = parent.getNodeType();
            if (type == Node.ELEMENT_NODE) {
                return parent;
            }
            parent = parent.getParentNode();
        }
        return null;
    }

    String lookupNamespacePrefix(String namespaceURI, ElementImpl el){
        String namespace = this.getNamespaceURI();
        // REVISIT: if no prefix is available is it null or empty string, or
        //          could be both?
        String prefix = this.getPrefix();

        if (namespace!=null && namespace.equals(namespaceURI)) {
            if (prefix != null) {
                String foundNamespace =  el.lookupNamespaceURI(prefix);
                if (foundNamespace !=null && foundNamespace.equals(namespaceURI)) {
                    return prefix;
                }

            }
        }
        if (this.hasAttributes()) {
            NamedNodeMap map = this.getAttributes();
            int length = map.getLength();
            for (int i=0;i<length;i++) {
                Node attr = map.item(i);
                namespace = attr.getNamespaceURI();
                if (namespace !=null && namespace.equals("http://www.w3.org/2000/xmlns/")) {
                    String attrPrefix = attr.getPrefix();
                    String value = attr.getNodeValue();
                    // DOM Level 2 nodes
                    if (((attr.getNodeName().equals("xmlns")) ||
                         (attrPrefix !=null && attrPrefix.equals("xmlns")) &&
                         value.equals(namespaceURI))) {

                        String localname= attr.getLocalName();
                        String foundNamespace = el.lookupNamespaceURI(localname);
                        if (foundNamespace !=null && foundNamespace.equals(namespaceURI)) {
                            return localname;
                        }
                    }


                }
            }
        }
        NodeImpl ancestor = (NodeImpl)getElementAncestor(this);

        if (ancestor != null) {
            return ancestor.lookupNamespacePrefix(namespaceURI, el);
        }
        return null;
    }

    Tests whether two nodes are equal.

This method tests for equality of nodes, not sameness (i.e.,
whether the two nodes are references to the same object) which can be
tested with Node.isSameNode. All nodes that are the same
will also be equal, though the reverse may not be true.

Two nodes are equal if and only if the following conditions are
satisfied: The two nodes are of the same type.The following string
attributes are equal: nodeName, localName,
namespaceURI, prefix, nodeValue
, baseURI. This is: they are both null, or
they have the same length and are character for character identical.
The attributes NamedNodeMaps are equal.
This is: they are both null, or they have the same
length and for each node that exists in one map there is a node that
exists in the other map and is equal, although not necessarily at the
same index.The childNodes NodeLists are
equal. This is: they are both null, or they have the
same length and contain equal nodes at the same index. This is true
for Attr nodes as for any other type of node. Note that
normalization can affect equality; to avoid this, nodes should be
normalized before being compared.

For two DocumentType nodes to be equal, the following
conditions must also be satisfied: The following string attributes
are equal: publicId, systemId,
internalSubset.The entities
NamedNodeMaps are equal.The notations
NamedNodeMaps are equal.

On the other hand, the following do not affect equality: the
ownerDocument attribute, the specified
attribute for Attr nodes, the
isWhitespaceInElementContent attribute for
Text nodes, as well as any user data or event listeners
registered on the nodes.
Params: arg – The node to compare equality with.
Returns: If the nodes, and possibly subtrees are equal,
  true otherwise false.
Since: DOM Level 3/**
     * Tests whether two nodes are equal.
     * <br>This method tests for equality of nodes, not sameness (i.e.,
     * whether the two nodes are references to the same object) which can be
     * tested with <code>Node.isSameNode</code>. All nodes that are the same
     * will also be equal, though the reverse may not be true.
     * <br>Two nodes are equal if and only if the following conditions are
     * satisfied: The two nodes are of the same type.The following string
     * attributes are equal: <code>nodeName</code>, <code>localName</code>,
     * <code>namespaceURI</code>, <code>prefix</code>, <code>nodeValue</code>
     * , <code>baseURI</code>. This is: they are both <code>null</code>, or
     * they have the same length and are character for character identical.
     * The <code>attributes</code> <code>NamedNodeMaps</code> are equal.
     * This is: they are both <code>null</code>, or they have the same
     * length and for each node that exists in one map there is a node that
     * exists in the other map and is equal, although not necessarily at the
     * same index.The <code>childNodes</code> <code>NodeLists</code> are
     * equal. This is: they are both <code>null</code>, or they have the
     * same length and contain equal nodes at the same index. This is true
     * for <code>Attr</code> nodes as for any other type of node. Note that
     * normalization can affect equality; to avoid this, nodes should be
     * normalized before being compared.
     * <br>For two <code>DocumentType</code> nodes to be equal, the following
     * conditions must also be satisfied: The following string attributes
     * are equal: <code>publicId</code>, <code>systemId</code>,
     * <code>internalSubset</code>.The <code>entities</code>
     * <code>NamedNodeMaps</code> are equal.The <code>notations</code>
     * <code>NamedNodeMaps</code> are equal.
     * <br>On the other hand, the following do not affect equality: the
     * <code>ownerDocument</code> attribute, the <code>specified</code>
     * attribute for <code>Attr</code> nodes, the
     * <code>isWhitespaceInElementContent</code> attribute for
     * <code>Text</code> nodes, as well as any user data or event listeners
     * registered on the nodes.
     * @param arg The node to compare equality with.
     * @return If the nodes, and possibly subtrees are equal,
     *   <code>true</code> otherwise <code>false</code>.
     * @since DOM Level 3
     */
    public boolean isEqualNode(Node arg) {
        if (arg == this) {
            return true;
        }
        if (arg.getNodeType() != getNodeType()) {
            return false;
        }
        // in theory nodeName can't be null but better be careful
        // who knows what other implementations may be doing?...
        if (getNodeName() == null) {
            if (arg.getNodeName() != null) {
                return false;
            }
        }
        else if (!getNodeName().equals(arg.getNodeName())) {
            return false;
        }

        if (getLocalName() == null) {
            if (arg.getLocalName() != null) {
                return false;
            }
        }
        else if (!getLocalName().equals(arg.getLocalName())) {
            return false;
        }

        if (getNamespaceURI() == null) {
            if (arg.getNamespaceURI() != null) {
                return false;
            }
        }
        else if (!getNamespaceURI().equals(arg.getNamespaceURI())) {
            return false;
        }

        if (getPrefix() == null) {
            if (arg.getPrefix() != null) {
                return false;
            }
        }
        else if (!getPrefix().equals(arg.getPrefix())) {
            return false;
        }

        if (getNodeValue() == null) {
            if (arg.getNodeValue() != null) {
                return false;
            }
        }
        else if (!getNodeValue().equals(arg.getNodeValue())) {
            return false;
        }


        return true;
    }

    Since: DOM Level 3/**
     * @since DOM Level 3
     */
    public Object getFeature(String feature, String version) {
        // we don't have any alternate node, either this node does the job
        // or we don't have anything that does
        return isSupported(feature, version) ? this : null;
    }

    Associate an object to a key on this node. The object can later be
retrieved from this node by calling getUserData with the
same key.
Params: key – The key to associate the object to.
data – The object to associate to the given key, or
  null to remove any existing association to that key.
handler – The handler to associate to that key, or
  null.
Returns: Returns the DOMObject previously associated to
  the given key on this node, or null if there was none.
Since: DOM Level 3/**
     * Associate an object to a key on this node. The object can later be
     * retrieved from this node by calling <code>getUserData</code> with the
     * same key.
     * @param key The key to associate the object to.
     * @param data The object to associate to the given key, or
     *   <code>null</code> to remove any existing association to that key.
     * @param handler The handler to associate to that key, or
     *   <code>null</code>.
     * @return Returns the <code>DOMObject</code> previously associated to
     *   the given key on this node, or <code>null</code> if there was none.
     * @since DOM Level 3
     */
    public Object setUserData(String key,
                              Object data,
                              UserDataHandler handler) {
        return ownerDocument().setUserData(this, key, data, handler);
    }

    Retrieves the object associated to a key on a this node. The object
must first have been set to this node by calling
setUserData with the same key.
Params: key – The key the object is associated to.
Returns: Returns the DOMObject associated to the given key
  on this node, or null if there was none.
Since: DOM Level 3/**
     * Retrieves the object associated to a key on a this node. The object
     * must first have been set to this node by calling
     * <code>setUserData</code> with the same key.
     * @param key The key the object is associated to.
     * @return Returns the <code>DOMObject</code> associated to the given key
     *   on this node, or <code>null</code> if there was none.
     * @since DOM Level 3
     */
    public Object getUserData(String key) {
        return ownerDocument().getUserData(this, key);
    }

    protected Map<String, ParentNode.UserDataRecord> getUserDataRecord(){
        return ownerDocument().getUserDataRecord(this);
        }

    //
    // Public methods
    //

    NON-DOM: PR-DOM-Level-1-19980818 mentions readonly nodes in conjunction
with Entities, but provides no API to support this.

Most DOM users should not touch this method. Its anticpated use
is during construction of EntityRefernces, where it will be used to
lock the contents replicated from Entity so they can't be casually
altered. It _could_ be published as a DOM extension, if desired.

Note: since we never have any children deep is meaningless here,
ParentNode overrides this behavior.
Params: readOnly – True or false as desired.
deep – If true, children are also toggled. Note that this will
 not change the state of an EntityReference or its children,
 which are always read-only.
See Also: ParentNode/**
     * NON-DOM: PR-DOM-Level-1-19980818 mentions readonly nodes in conjunction
     * with Entities, but provides no API to support this.
     * <P>
     * Most DOM users should not touch this method. Its anticpated use
     * is during construction of EntityRefernces, where it will be used to
     * lock the contents replicated from Entity so they can't be casually
     * altered. It _could_ be published as a DOM extension, if desired.
     * <P>
     * Note: since we never have any children deep is meaningless here,
     * ParentNode overrides this behavior.
     * @see ParentNode
     *
     * @param readOnly True or false as desired.
     * @param deep If true, children are also toggled. Note that this will
     *  not change the state of an EntityReference or its children,
     *  which are always read-only.
     */
    public void setReadOnly(boolean readOnly, boolean deep) {

        if (needsSyncData()) {
            synchronizeData();
        }
        isReadOnly(readOnly);

    } // setReadOnly(boolean,boolean)

    NON-DOM: Returns true if this node is read-only. This is a
shallow check.
/**
     * NON-DOM: Returns true if this node is read-only. This is a
     * shallow check.
     */
    public boolean getReadOnly() {

        if (needsSyncData()) {
            synchronizeData();
        }
        return isReadOnly();

    } // getReadOnly():boolean

    NON-DOM: As an alternative to subclassing the DOM, this implementation
has been extended with the ability to attach an object to each node.
(If you need multiple objects, you can attach a collection such as a
List or Map, then attach your application information to that.)
Important Note: You are responsible for removing references
to your data on nodes that are no longer used. Failure to do so will
prevent the nodes, your data is attached to, to be garbage collected
until the whole document is.
Params: data – the object to store or null to remove any existing reference/**
     * NON-DOM: As an alternative to subclassing the DOM, this implementation
     * has been extended with the ability to attach an object to each node.
     * (If you need multiple objects, you can attach a collection such as a
     * List or Map, then attach your application information to that.)
     * <p><b>Important Note:</b> You are responsible for removing references
     * to your data on nodes that are no longer used. Failure to do so will
     * prevent the nodes, your data is attached to, to be garbage collected
     * until the whole document is.
     *
     * @param data the object to store or null to remove any existing reference
     */
    public void setUserData(Object data) {
        ownerDocument().setUserData(this, data);
    }

    NON-DOM:
Returns the user data associated to this node.
/**
     * NON-DOM:
     * Returns the user data associated to this node.
     */
    public Object getUserData() {
        return ownerDocument().getUserData(this);
    }

    //
    // Protected methods
    //

    Denotes that this node has changed.
/**
     * Denotes that this node has changed.
     */
    protected void changed() {
        // we do not actually store this information on every node, we only
        // have a global indicator on the Document. Doing otherwise cost us too
        // much for little gain.
        ownerDocument().changed();
    }

    Returns the number of changes to this node.
/**
     * Returns the number of changes to this node.
     */
    protected int changes() {
        // we do not actually store this information on every node, we only
        // have a global indicator on the Document. Doing otherwise cost us too
        // much for little gain.
        return ownerDocument().changes();
    }

    Override this method in subclass to hook in efficient
internal data structure.
/**
     * Override this method in subclass to hook in efficient
     * internal data structure.
     */
    protected void synchronizeData() {
        // By default just change the flag to avoid calling this method again
        needsSyncData(false);
    }

    For non-child nodes, the node which "points" to this node.
For example, the owning element for an attribute
/**
     * For non-child nodes, the node which "points" to this node.
     * For example, the owning element for an attribute
     */
    protected Node getContainer() {
       return null;
    }


    /*
     * Flags setters and getters
     */

    final boolean isReadOnly() {
        return (flags & READONLY) != 0;
    }

    final void isReadOnly(boolean value) {
        flags = (short) (value ? flags | READONLY : flags & ~READONLY);
    }

    final boolean needsSyncData() {
        return (flags & SYNCDATA) != 0;
    }

    final void needsSyncData(boolean value) {
        flags = (short) (value ? flags | SYNCDATA : flags & ~SYNCDATA);
    }

    final boolean needsSyncChildren() {
        return (flags & SYNCCHILDREN) != 0;
    }

    public final void needsSyncChildren(boolean value) {
        flags = (short) (value ? flags | SYNCCHILDREN : flags & ~SYNCCHILDREN);
    }

    final boolean isOwned() {
        return (flags & OWNED) != 0;
    }

    final void isOwned(boolean value) {
        flags = (short) (value ? flags | OWNED : flags & ~OWNED);
    }

    final boolean isFirstChild() {
        return (flags & FIRSTCHILD) != 0;
    }

    final void isFirstChild(boolean value) {
        flags = (short) (value ? flags | FIRSTCHILD : flags & ~FIRSTCHILD);
    }

    final boolean isSpecified() {
        return (flags & SPECIFIED) != 0;
    }

    final void isSpecified(boolean value) {
        flags = (short) (value ? flags | SPECIFIED : flags & ~SPECIFIED);
    }

    // inconsistent name to avoid clash with public method on TextImpl
    final boolean internalIsIgnorableWhitespace() {
        return (flags & IGNORABLEWS) != 0;
    }

    final void isIgnorableWhitespace(boolean value) {
        flags = (short) (value ? flags | IGNORABLEWS : flags & ~IGNORABLEWS);
    }

    final boolean hasStringValue() {
        return (flags & HASSTRING) != 0;
    }

    final void hasStringValue(boolean value) {
        flags = (short) (value ? flags | HASSTRING : flags & ~HASSTRING);
    }

    final boolean isNormalized() {
        return (flags & NORMALIZED) != 0;
    }

    final void isNormalized(boolean value) {
        // See if flag should propagate to parent.
        if (!value && isNormalized() && ownerNode != null) {
            ownerNode.isNormalized(false);
        }
        flags = (short) (value ?  flags | NORMALIZED : flags & ~NORMALIZED);
    }

    final boolean isIdAttribute() {
        return (flags & ID) != 0;
    }

    final void isIdAttribute(boolean value) {
        flags = (short) (value ? flags | ID : flags & ~ID);
    }

    //
    // Object methods
    //

    NON-DOM method for debugging convenience. /** NON-DOM method for debugging convenience. */
    public String toString() {
        return "["+getNodeName()+": "+getNodeValue()+"]";
    }

    //
    // Serialization methods
    //

    Serialize object. /** Serialize object. */
    private void writeObject(ObjectOutputStream out) throws IOException {

        // synchronize data
        if (needsSyncData()) {
            synchronizeData();
        }
        // write object
        out.defaultWriteObject();

    } // writeObject(ObjectOutputStream)

} // class NodeImpl
Author:	Arnaud Le Hors, IBM, Joe Kesselman, IBM
@xerces.internal
Since:	PR-DOM-Level-1-19980818.
@LastModified	: Apr 2019
Throws:	DOMException – (HIERARCHY_REQUEST_ERR) if newChild is of a type that shouldn't be a child of this node. DOMException – (WRONG_DOCUMENT_ERR) if newChild has a different owner document than we do. DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is read-only.
See Also:	By default we do not accept any children, ParentNode overrides this. ParentNode
Returns:	newChild, in its new state (relocated, or emptied in the case of DocumentNode.)
See Also:	ElementImpl
Returns:	`true` if this node has any attributes, `false` otherwise.
Since:	DOM Level 2
Params:	newChild – The Node to be moved to our subtree. As a convenience feature, inserting a DocumentNode will instead insert all its children. refChild – Current child which newChild should be placed immediately before. If refChild is null, the insertion occurs after all existing Nodes, like appendChild().
Throws:	DOMException – (HIERARCHY_REQUEST_ERR) if newChild is of a type that shouldn't be a child of this node, or if newChild is an ancestor of this node. DOMException – (WRONG_DOCUMENT_ERR) if newChild has a different owner document than we do. DOMException – (NOT_FOUND_ERR) if refChild is not a child of this node. DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is read-only.
See Also:	ParentNode
Returns:	newChild, in its new state (relocated, or emptied in the case of DocumentNode.)
Throws:	DOMException – (NOT_FOUND_ERR) if oldChild is not a child of this node. DOMException – (NO_MODIFICATION_ALLOWED_ERR) if this node is read-only.
See Also:	ParentNode
Returns:	oldChild, in its new state (removed).
Params:	index – int
See Also:	ParentNode
Returns:	org.w3c.dom.Node
Params:	feature – The package name of the feature to test. This is the same name as what can be passed to the method hasFeature on DOMImplementation. version – This is the version number of the package name to test. In Level 2, version 1, this is the string "2.0". If the version is not specified, supporting any version of the feature will cause the method to return true.
Returns:	boolean Returns true if this node defines a subtree within which the specified feature is supported, false otherwise.
Since:	WD-DOM-Level-2-19990923
See Also:	AttrNSImpl ElementNSImpl
Since:	WD-DOM-Level-2-19990923
Throws:	INVALID_CHARACTER_ERR – Raised if the specified prefix contains an invalid character.
See Also:	AttrNSImpl ElementNSImpl
Since:	WD-DOM-Level-2-19990923
Params:	other – The node to compare against this node.
Returns:	Returns how the given node is positioned relatively to this node.
Since:	DOM Level 3
Deprecated:
Node type	Content
ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, DOCUMENT_FRAGMENT_NODE	concatenation of the `textContent` attribute value of every child node, excluding COMMENT_NODE and PROCESSING_INSTRUCTION_NODE nodes
ATTRIBUTE_NODE, TEXT_NODE, CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE	`nodeValue`
DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE	null
Throws:	DOMException – NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly. DOMException – DOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in a `DOMString` variable on the implementation platform.
Since:	DOM Level 3
Params:	other – The node to test against.
Returns:	Returns `true` if the nodes are the same, `false` otherwise.
Since:	DOM Level 3
Params:	specifiedPrefix –
Returns:	the URI for the namespace
Since:	DOM Level 3
Params:	arg – The node to compare equality with.
Returns:	If the nodes, and possibly subtrees are equal, `true` otherwise `false`.
Since:	DOM Level 3
Params:	key – The key to associate the object to. data – The object to associate to the given key, or `null` to remove any existing association to that key. handler – The handler to associate to that key, or `null`.
Returns:	Returns the `DOMObject` previously associated to the given key on this node, or `null` if there was none.
Since:	DOM Level 3
Params:	key – The key the object is associated to.
Returns:	Returns the `DOMObject` associated to the given key on this node, or `null` if there was none.
Since:	DOM Level 3
Params:	readOnly – True or false as desired. deep – If true, children are also toggled. Note that this will not change the state of an EntityReference or its children, which are always read-only.
See Also:	ParentNode
/

java/ 11/ java.xml/com/sun/org/apache/xerces/internal/dom/NodeImpl.java
