context: //
  // System.Xml.XmlElement
  //
  // Author:
  //   Jason Diamond (jason@injektilo.org)
  //   Atsushi Enomoto (ginga@kit.hi-ho.ne.jp)
  //
  // (C) 2002 Jason Diamond  http://injektilo.org/
  // (C) 2002 Atsushi Enomoto
  //
  
  //
  // Permission is hereby granted, free of charge, to any person obtaining
  // a copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to
  // permit persons to whom the Software is furnished to do so, subject to
  // the following conditions:
  // 
  // The above copyright notice and this permission notice shall be
  // included in all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  //
  
  using System;
  using System.Collections;
  using System.Xml.XPath;
  using System.IO;
  using System.Text;
  using Mono.Xml;
  using System.Xml.Schema;
  
  namespace System.Xml
  {
  	public class XmlElement : XmlLinkedNode, IHasXmlChildNode
  	{
  		#region Fields
  
  		private XmlAttributeCollection attributes;
  		private XmlNameEntry name;
  		XmlLinkedNode lastLinkedChild;
  
  		private bool isNotEmpty;
  		IXmlSchemaInfo schemaInfo;
  
  		#endregion
  
  		#region Constructor
  
  		protected internal XmlElement (
  			string prefix, 
  			string localName, 
  			string namespaceURI, 
  			XmlDocument doc) : this (prefix, localName, namespaceURI, doc, false)
  		{
  		}
  
  		internal XmlElement (
  			string prefix, 
  			string localName, 
  			string namespaceURI, 
  			XmlDocument doc,
  			bool atomizedNames) : base (doc)
  		{
  			if (!atomizedNames) {
  				if (prefix == null)
  					prefix = String.Empty;
  				if (namespaceURI == null)
  					namespaceURI = String.Empty;
  
  				XmlConvert.VerifyName (localName);
  
  				prefix = doc.NameTable.Add (prefix);
  				localName = doc.NameTable.Add (localName);
  				namespaceURI = doc.NameTable.Add (namespaceURI);
  			}
  			name = doc.NameCache.Add (prefix, localName, namespaceURI, true);
  
  			if(doc.DocumentType != null)
  			{
  				DTDAttListDeclaration attlist = doc.DocumentType.DTD.AttListDecls [localName];
  				if (attlist != null) {
  					for (int i = 0; i < attlist.Definitions.Count; i++) {
  						DTDAttributeDefinition def = attlist [i];
  						if (def.DefaultValue != null) {
  							SetAttribute (def.Name, def.DefaultValue);
  							Attributes [def.Name].SetDefault ();
  						}
  					}
  				}
  			}
  		}
  
  		#endregion
  
  		#region Properties
  
  		XmlLinkedNode IHasXmlChildNode.LastLinkedChild {
  			get { return lastLinkedChild; }
  			set { lastLinkedChild = value; }
  		}
  
  		public override XmlAttributeCollection Attributes {
  			get {
  				if (attributes == null)
  					attributes = new XmlAttributeCollection (this);
  				return attributes;
  			}
  		}
  
  		public virtual bool HasAttributes {
  			get { return attributes != null && attributes.Count > 0; }
  		}
  
  		public override string InnerText {
  			get {
  				return base.InnerText;
  			}
  			set {
  				// Why its behavior (of MS FCL) is different from InnerXml...?
  				if (FirstChild != null && FirstChild.NextSibling == null && FirstChild.NodeType == XmlNodeType.Text)
  					FirstChild.Value = value;
  				else {
  					while (FirstChild != null)
  						this.RemoveChild (FirstChild);
  					// creates new Text node
  					AppendChild (OwnerDocument.CreateTextNode (value), false);
  				}
  			}
  		}
  
  		public override string InnerXml {
  			get {
  				return base.InnerXml;
  			}
  			set {
  				while (FirstChild != null)
  					this.RemoveChild (FirstChild);
  
  				XmlNamespaceManager nsmgr = this.ConstructNamespaceManager ();
  				XmlParserContext ctx = new XmlParserContext (OwnerDocument.NameTable, nsmgr,
  					OwnerDocument.DocumentType != null ? OwnerDocument.DocumentType.DTD : null,
  					BaseURI, XmlLang, XmlSpace, null);
  				XmlTextReader xmlReader = new XmlTextReader (value, XmlNodeType.Element, ctx);
  				xmlReader.XmlResolver = OwnerDocument.Resolver;
  
  				do {
  					XmlNode n = OwnerDocument.ReadNode (xmlReader);
  					if(n == null) break;
  					AppendChild (n);
  				} while (true);
  			}
  		}
  
  		public bool IsEmpty {
  			get {
  				return !isNotEmpty && (FirstChild == null);
  			}
  
  			set {
  				isNotEmpty = !value;
  				if(value) {
  					while (FirstChild != null)
  						RemoveChild (FirstChild);
  				}
  			}
  		}
  
  		public override string LocalName {
  			get { return name.LocalName; }
  		}
  
  		public override string Name {
  			get { return name.GetPrefixedName (OwnerDocument.NameCache); }
  		}
  
  		public override string NamespaceURI {
  			get { return name.NS; }
  		}
  
  		public override XmlNode NextSibling {
  			get { return ParentNode == null || ((IHasXmlChildNode) ParentNode).LastLinkedChild == this ? null : NextLinkedSibling; }
  		}
  
  		public override XmlNodeType NodeType {
  			get { 
  				return XmlNodeType.Element; 
  			}
  		}
  
  		internal override XPathNodeType XPathNodeType {
  			get {
  				return XPathNodeType.Element;
  			}
  		}
  
  		public override XmlDocument OwnerDocument {
  			get { 
  				return base.OwnerDocument; 
  			}
  		}
  
  		public override string Prefix {
  			get { return name.Prefix; }
  			set {
  				if (IsReadOnly)
  					throw new ArgumentException ("This node is readonly.");
  				if (value == null) {
  					value = string.Empty;
  				}
  				if ((!String.Empty.Equals(value))&&(!XmlChar.IsNCName (value)))
  					throw new ArgumentException ("Specified name is not a valid NCName: " + value);
  
  				value = OwnerDocument.NameTable.Add (value);
  				name = OwnerDocument.NameCache.Add (value,
  					name.LocalName, name.NS, true);
  			}
  		}
  
  		public override XmlNode ParentNode {
  			get { return base.ParentNode; }
  		}
  
  		public override IXmlSchemaInfo SchemaInfo {
  			get { return schemaInfo; }
  			internal set { schemaInfo = value; }
  		}
  
  		#endregion
  
  		#region Methods
  		
  		public override XmlNode CloneNode (bool deep)
  		{
  			XmlElement node = OwnerDocument.CreateElement (
  				name.Prefix, name.LocalName, name.NS, true);
  
  			for (int i = 0; i < Attributes.Count; i++)
  				node.SetAttributeNode ((XmlAttribute) 
  					Attributes [i].CloneNode (true));
  
  			if (deep) {
  				for (int i = 0; i < ChildNodes.Count; i++)
  					node.AppendChild (ChildNodes [i].CloneNode (true), false);
  			}
  
  			return node;
  		}
  
  		public virtual string GetAttribute (string name)
  		{
  			XmlNode attributeNode = Attributes.GetNamedItem (name);
  			return attributeNode != null ? attributeNode.Value : String.Empty;
  		}
  
  		public virtual string GetAttribute (string localName, string namespaceURI)
  		{
  			XmlNode attributeNode = Attributes.GetNamedItem (localName, namespaceURI);
  			return attributeNode != null ? attributeNode.Value : String.Empty;
  		}
  
  		public virtual XmlAttribute GetAttributeNode (string name)
  		{
  			XmlNode attributeNode = Attributes.GetNamedItem (name);
  			return attributeNode != null ? attributeNode as XmlAttribute : null;
  		}
  
  		public virtual XmlAttribute GetAttributeNode (string localName, string namespaceURI)
  		{
  			XmlNode attributeNode = Attributes.GetNamedItem (localName, namespaceURI);
  			return attributeNode != null ? attributeNode as XmlAttribute : null;
  		}
  
  		public virtual XmlNodeList GetElementsByTagName (string name)
  		{
  			ArrayList nodeArrayList = new ArrayList ();
  			this.SearchDescendantElements (name, name == "*", nodeArrayList);
  			return new XmlNodeArrayList (nodeArrayList);
  		}
  
  		public virtual XmlNodeList GetElementsByTagName (string localName, string namespaceURI)
  		{
  			ArrayList nodeArrayList = new ArrayList ();
  			this.SearchDescendantElements (localName, localName == "*", namespaceURI, namespaceURI == "*", nodeArrayList);
  			return new XmlNodeArrayList (nodeArrayList);
  		}
  
  		public virtual bool HasAttribute (string name)
  		{
  			XmlNode attributeNode = Attributes.GetNamedItem (name);
  			return attributeNode != null;
  		}
  
  		public virtual bool HasAttribute (string localName, string namespaceURI)
  		{
  			XmlNode attributeNode = Attributes.GetNamedItem (localName, namespaceURI);
  			return attributeNode != null;
  		}
  
  		public override void RemoveAll ()
  		{
  			// Remove all attributes and child nodes.
  			base.RemoveAll ();
  		}
  
  		public virtual void RemoveAllAttributes ()
  		{
  			if (attributes != null)
  				attributes.RemoveAll ();
  		}
  
  		public virtual void RemoveAttribute (string name)
  		{
  			if (attributes == null)
  				return;
  			XmlAttribute attr = Attributes.GetNamedItem (name) as XmlAttribute;
  			if (attr != null)
  				Attributes.Remove(attr);
  		}
  
  		public virtual void RemoveAttribute (string localName, string namespaceURI)
  		{
  			if (attributes == null)
  				return;
  
  			XmlAttribute attr = attributes.GetNamedItem(localName, namespaceURI) as XmlAttribute;
  			if (attr != null)
  				Attributes.Remove(attr);
  		}
  
  		public virtual XmlNode RemoveAttributeAt (int i)
  		{
  			if (attributes == null || attributes.Count <= i)
  				return null;
  			return Attributes.RemoveAt (i);
  		}
  
  		public virtual XmlAttribute RemoveAttributeNode (XmlAttribute oldAttr)
  		{
  
gt: 			if (attributes == null)