SmiMetaDataProperty.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / Microsoft / SqlServer / Server / SmiMetaDataProperty.cs / 1 / SmiMetaDataProperty.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
namespace Microsoft.SqlServer.Server {
 
    using System;
    using System.Collections.Generic;
    using System.Data;
    using System.Data.Common; 
    using System.Data.SqlClient;
    using System.Diagnostics; 
    using System.Globalization; 

    // SmiMetaDataProperty defines an extended, optional property to be used on the SmiMetaData class 
    //  This approach to adding properties is added combat the growing number of sparsely-used properties
    //  that are specially handled on the base classes

    internal enum SmiPropertySelector { 
        DefaultFields = 0x0,
        SortOrder = 0x1, 
        UniqueKey = 0x2, 
    }
 
    // Simple collection for properties.  Could extend to IDictionary support if needed in future.
    internal class SmiMetaDataPropertyCollection {
        private const int               SelectorCount = 3;  // number of elements in SmiPropertySelector
 
        private SmiMetaDataProperty[]   _properties;
        private bool                    _isReadOnly; 
 
        internal static readonly SmiMetaDataPropertyCollection EmptyInstance;
 
        // Singleton empty instances to ensure each property is always non-null
        private static readonly SmiDefaultFieldsProperty    __emptyDefaultFields = new SmiDefaultFieldsProperty(new List());
        private static readonly SmiOrderProperty            __emptySortOrder = new SmiOrderProperty(new List());
        private static readonly SmiUniqueKeyProperty        __emptyUniqueKey = new SmiUniqueKeyProperty(new List()); 

        static SmiMetaDataPropertyCollection() { 
            EmptyInstance = new SmiMetaDataPropertyCollection(); 
            EmptyInstance.SetReadOnly();
        } 

        internal SmiMetaDataPropertyCollection() {
            _properties = new SmiMetaDataProperty[SelectorCount];
            _isReadOnly = false; 
            _properties[(int)SmiPropertySelector.DefaultFields]  = __emptyDefaultFields;
            _properties[(int)SmiPropertySelector.SortOrder]      = __emptySortOrder; 
            _properties[(int)SmiPropertySelector.UniqueKey]      = __emptyUniqueKey; 
        }
 
        internal SmiMetaDataProperty this[SmiPropertySelector key] {
            get {
                return _properties[(int)key];
            } 
            set {
                if (null == value) { 
                    throw ADP.InternalError(ADP.InternalErrorCode.InvalidSmiCall); 
                }
                EnsureWritable(); 
                _properties[(int)key] = value;
            }
        }
 
        internal bool IsReadOnly {
            get { 
                return _isReadOnly; 
            }
        } 

        internal IEnumerable Values {
            get {
                return new List(_properties); 
            }
        } 
 
        // Allow switching to read only, but not back.
        internal void SetReadOnly() { 
            _isReadOnly = true;
        }

        private void EnsureWritable() { 
            if (IsReadOnly) {
                throw System.Data.Common.ADP.InternalError(System.Data.Common.ADP.InternalErrorCode.InvalidSmiCall); 
            } 
        }
    } 

    // Base class for properties
    internal abstract class SmiMetaDataProperty {
        internal abstract string TraceString(); 
    }
 
    // Property defining a list of column ordinals that define a unique key 
    internal class SmiUniqueKeyProperty : SmiMetaDataProperty {
        private IList _columns; 

        internal SmiUniqueKeyProperty(IList columnIsKey) {
            _columns = new List(columnIsKey).AsReadOnly();
        } 

        // indexed by column ordinal indicating for each column whether it is key or not 
        internal bool this[int ordinal] { 
            get {
                if (_columns.Count <= ordinal) { 
                    return false;
                }
                else {
                    return _columns[ordinal]; 
                }
            } 
        } 

        [Conditional("DEBUG")] 
        internal void CheckCount(int countToMatch) {
            Debug.Assert(0 == _columns.Count || countToMatch == _columns.Count,
                    "SmiDefaultFieldsProperty.CheckCount: DefaultFieldsProperty size (" + _columns.Count +
                    ") not equal to checked size (" + countToMatch + ")" ); 
        }
 
        internal override string TraceString() { 
            string returnValue = "UniqueKey(";
            bool delimit = false; 
            for (int columnOrd = 0; columnOrd < _columns.Count; columnOrd++) {
                if (delimit) {
                    returnValue += ",";
                } 
                else {
                    delimit = true; 
                } 
                if (_columns[columnOrd]) {
                    returnValue += columnOrd.ToString(CultureInfo.InvariantCulture); 
                }
            }
            returnValue += ")";
 
            return returnValue;
        } 
    } 

    // Property defining a sort order for a set of columns (by ordinal and ASC/DESC). 
    internal class SmiOrderProperty : SmiMetaDataProperty {
        internal struct SmiColumnOrder {
            internal int SortOrdinal;
            internal SortOrder Order; 

            internal string TraceString() { 
                return String.Format(CultureInfo.InvariantCulture, "{0} {1}", SortOrdinal, Order); 
            }
        } 

        private IList _columns;

        internal SmiOrderProperty(IList columnOrders) { 
            _columns = new List(columnOrders).AsReadOnly();
        } 
 
        // Readonly list of the columnorder instances making up the sort order
        //  order in list indicates precedence 
        internal SmiColumnOrder this[int ordinal] {
            get {
                if (_columns.Count <= ordinal) {
                    SmiColumnOrder order = new SmiColumnOrder(); 
                    order.Order = SortOrder.Unspecified;
                    order.SortOrdinal = -1; 
                    return order; 
                }
                else { 
                    return _columns[ordinal];
                }
            }
        } 

 
        [Conditional("DEBUG")] 
        internal void CheckCount(int countToMatch) {
            Debug.Assert(0 == _columns.Count || countToMatch == _columns.Count, 
                    "SmiDefaultFieldsProperty.CheckCount: DefaultFieldsProperty size (" + _columns.Count +
                    ") not equal to checked size (" + countToMatch + ")" );
        }
 
        internal override string TraceString() {
            string returnValue = "SortOrder("; 
            bool delimit = false; 
            foreach(SmiColumnOrder columnOrd in _columns) {
                if (delimit) { 
                    returnValue += ",";
                }
                else {
                    delimit = true; 
                }
 
                if (System.Data.SqlClient.SortOrder.Unspecified != columnOrd.Order) { 
                    returnValue += columnOrd.TraceString();
                } 
            }
            returnValue += ")";

            return returnValue; 
         }
    } 
 
    // property defining inheritance relationship(s)
    internal class SmiDefaultFieldsProperty : SmiMetaDataProperty { 
        #region private fields

        private IList     _defaults;
 
        #endregion
 
        #region internal interface 

        internal SmiDefaultFieldsProperty(IList defaultFields) { 
            _defaults = new List(defaultFields).AsReadOnly();
        }

        internal bool this[int ordinal] { 
            get {
                if (_defaults.Count <= ordinal) { 
                    return false; 
                }
                else { 
                    return _defaults[ordinal];
                }
            }
        } 

        [Conditional("DEBUG")] 
        internal void CheckCount(int countToMatch) { 
            Debug.Assert(0 == _defaults.Count || countToMatch == _defaults.Count,
                    "SmiDefaultFieldsProperty.CheckCount: DefaultFieldsProperty size (" + _defaults.Count + 
                    ") not equal to checked size (" + countToMatch + ")" );
        }

        internal override string TraceString() { 
            string returnValue = "DefaultFields(";
            bool delimit = false; 
            for(int columnOrd = 0; columnOrd < _defaults.Count; columnOrd++) { 
                if (delimit) {
                    returnValue += ","; 
                }
                else {
                    delimit = true;
                } 

                if (_defaults[columnOrd]) { 
                    returnValue += columnOrd; 
                }
            } 
            returnValue += ")";

            return returnValue;
         } 

        #endregion 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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