//---------------------------------------------------------------------
// <copyright file="ReferenceSchema.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// @owner       Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
 
namespace System.Data.EntityModel.SchemaObjectModel
{
    using System;
    using System.Data.Metadata.Edm;
    using System.Diagnostics;
    using System.Xml;
 
    /// <summary>
    /// Summary description for UsingElement.
    /// </summary>
    internal class UsingElement : SchemaElement
    {
        #region Instance Fields
        private string _alias = null;
        private string _namespaceName = null;
        #endregion
 
        #region Public Methods
        /// <summary>
        /// 
        /// </summary>
        /// <param name="parentElement"></param>
        internal UsingElement(Schema parentElement)
        :   base(parentElement)
        {
        }
 
        #endregion
 
        #region Public Properties
        /// <summary>
        /// 
        /// </summary>
        public virtual string Alias
        {
            get
            {
                return _alias;
            }
            private set
            {
                _alias = value;
            }
        }
 
        /// <summary>
        /// 
        /// </summary>
        public virtual string NamespaceName
        {
            get
            {
                return _namespaceName;
            }
            private set
            {
                _namespaceName = value;
            }
        }
 
        /// <summary>
        /// 
        /// </summary>
        public override string FQName
        {
            get
            {
                return null;
            }
        }
 
        #endregion
 
        #region Protected Properties
        /// <summary>
        /// 
        /// </summary>
        protected override bool ProhibitAttribute(string namespaceUri, string localName)
        {
            if (base.ProhibitAttribute(namespaceUri, localName))
            {
                return true;
            }
 
            if (namespaceUri == null && localName == XmlConstants.Name)
            {
                return false;
            }
            return false;
 
        }
        
        protected override bool HandleAttribute(XmlReader reader)
        {
            if (base.HandleAttribute(reader))
            {
                return true;
            }
            else if (CanHandleAttribute(reader, XmlConstants.Namespace))
            {
                HandleNamespaceAttribute(reader);
                return true;
            }
            else if (CanHandleAttribute(reader, XmlConstants.Alias))
            {
                HandleAliasAttribute(reader);
                return true;
            }
 
            return false;
        }
 
        #endregion
 
        #region Private Methods
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="reader"></param>
        private void HandleNamespaceAttribute(XmlReader reader)
        {
            Debug.Assert(String.IsNullOrEmpty(NamespaceName), "Alias must be set only once");
            ReturnValue<string> returnValue = HandleDottedNameAttribute(reader,NamespaceName, null);
            if ( returnValue.Succeeded )
                NamespaceName = returnValue.Value;
        }
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="reader"></param>
        private void HandleAliasAttribute(XmlReader reader)
        {
            Debug.Assert(String.IsNullOrEmpty(Alias), "Alias must be set only once");
            Alias = HandleUndottedNameAttribute(reader, Alias);
        }
        #endregion
    }
}