SchemaLookupTable.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / EntityModel / SchemaObjectModel / SchemaLookupTable.cs / 1305376 / SchemaLookupTable.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 
using System;
using System.Collections; 
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Data;
using System.Data.Metadata.Edm; 
using System.Diagnostics;
using System.Data.Entity; 
 

namespace System.Data.EntityModel.SchemaObjectModel 
{
    /// 
    /// Reponsible for keep map from alias to namespace for a given schema.
    ///  
    internal sealed class AliasResolver
    { 
        #region Fields 
        private Dictionary _aliasToNamespaceMap = new Dictionary(StringComparer.Ordinal);
        private List _usingElementCollection = new List(); 
        private Schema _definingSchema;
        #endregion

        #region Public Methods 
        /// 
        /// Construct the LookUp table 
        ///  
        public AliasResolver(Schema schema)
        { 
            _definingSchema = schema;

            // If there is an alias defined for the defining schema,
            // add it to the look up table 
            if (!string.IsNullOrEmpty(schema.Alias))
            { 
                _aliasToNamespaceMap.Add(schema.Alias, schema.Namespace); 
            }
        } 

        /// 
        /// Add a ReferenceSchema to the table
        ///  
        /// the ReferenceSchema to add
        public void Add(UsingElement usingElement) 
        { 
            Debug.Assert(usingElement != null, "refSchema parameter is null");
            string newNamespace = usingElement.NamespaceName; 
            string newAlias = usingElement.Alias;

            // Check whether the alias is a reserved keyword
            if (CheckForSystemNamespace(usingElement, newAlias, NameKind.Alias)) 
            {
                newAlias = null; 
            } 

            //Check whether the namespace is a reserved keyword 
            if (CheckForSystemNamespace(usingElement, newNamespace, NameKind.Namespace))
            {
                newNamespace = null;
            } 

            // see if the alias has already been used 
            if (newAlias != null && _aliasToNamespaceMap.ContainsKey(newAlias)) 
            {
                // it has, issue an error and make sure we don't try to add it 
                usingElement.AddError(ErrorCode.AlreadyDefined, EdmSchemaErrorSeverity.Error, System.Data.Entity.Strings.AliasNameIsAlreadyDefined(newAlias));
                newAlias = null;
            }
 
            // Its okay if they add the same namespace twice, until they have different alias
 
            // if there's an alias, add it. 
            if (newAlias != null)
            { 
                _aliasToNamespaceMap.Add(newAlias, newNamespace);
                _usingElementCollection.Add(usingElement);
            }
        } 

        ///  
        /// Get the Schema(s) a namespace or alias might refer to 
        /// returned schemas may be null is called before or during Schema Resolution
        ///  
        /// the name to look up
        /// array of schemas (0 length if no schemas match name
        public bool TryResolveAlias(string alias, out string namespaceName)
        { 
            Debug.Assert(!String.IsNullOrEmpty(alias), "alias must never be null");
 
            // Check if there is an alias defined with this name 
            return _aliasToNamespaceMap.TryGetValue(alias, out namespaceName);
        } 

        /// 
        /// Resolves all the namespace specified in the using elements in this schema
        ///  
        public void ResolveNamespaces()
        { 
            foreach (UsingElement usingElement in _usingElementCollection) 
            {
                if (!_definingSchema.SchemaManager.IsValidNamespaceName(usingElement.NamespaceName)) 
                {
                    usingElement.AddError(ErrorCode.InvalidNamespaceInUsing, EdmSchemaErrorSeverity.Error,
                        System.Data.Entity.Strings.InvalidNamespaceInUsing(usingElement.NamespaceName));
                } 
            }
        } 
 
        #endregion
 
        #region Private Methods

        /// 
        /// Check if the given name is a reserved keyword. if yes, add appropriate error to the refschema 
        /// 
        ///  
        ///  
        /// 
        ///  
        private bool CheckForSystemNamespace(UsingElement refSchema, string name, NameKind nameKind)
        {
            Debug.Assert(_definingSchema.ProviderManifest != null, "Since we don't allow using elements in provider manifest, provider manifest can never be null");
 
            // We need to check for system namespace
            if (EdmItemCollection.IsSystemNamespace(_definingSchema.ProviderManifest, name)) 
            { 
                if (nameKind == NameKind.Alias)
                { 
                    refSchema.AddError(ErrorCode.CannotUseSystemNamespaceAsAlias, EdmSchemaErrorSeverity.Error,
                        System.Data.Entity.Strings.CannotUseSystemNamespaceAsAlias(name));
                }
                else 
                {
                    refSchema.AddError(ErrorCode.NeedNotUseSystemNamespaceInUsing, EdmSchemaErrorSeverity.Error, 
                        System.Data.Entity.Strings.NeedNotUseSystemNamespaceInUsing(name)); 
                }
                return true; 
            }
            return false;
        }
        #endregion 

        #region Private Types 
        ///  
        /// Kind of Name
        ///  
        private enum NameKind
        {
            /// It's an Alias
            Alias, 
            /// It's a namespace
            Namespace, 
        } 
        #endregion
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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SchemaLookupTable.cs source code in C# .NET

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