FilteredReadOnlyMetadataCollection.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Metadata / Edm / FilteredReadOnlyMetadataCollection.cs / 1305376 / FilteredReadOnlyMetadataCollection.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System; 
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data.Common; 
using System.Diagnostics;
using System.Reflection; 
using System.Text; 

namespace System.Data.Metadata.Edm 
{
    internal interface IBaseList : IList
    {
        T this[string identity] { get;} 

        new T this[int index] { get;} 
 
        int IndexOf(T item);
    } 

#pragma warning disable 1711 // compiler bug: reports TDerived and TBase as type parameters for non-existing IsReadOnly property
    /// 
    /// Class to filter stuff out from a metadata collection 
    /// 
    /* 
 

*/ 
    internal class FilteredReadOnlyMetadataCollection : ReadOnlyMetadataCollection, IBaseList
                where TDerived : TBase
                where TBase : MetadataItem
    { 
        #region Constructors
        ///  
        /// The constructor for constructing a read-only metadata collection to wrap another MetadataCollection. 
        /// 
        /// The metadata collection to wrap 
        /// Thrown if collection argument is null
        /// Predicate method which determines membership
        internal FilteredReadOnlyMetadataCollection(ReadOnlyMetadataCollection collection, Predicate predicate) : base(FilterCollection(collection, predicate))
        { 
            Debug.Assert(collection != null);
            Debug.Assert(collection.IsReadOnly, "wrappers should only be created once loading is over, and this collection is still loading"); 
            _source = collection; 
            _predicate = predicate;
 
        }
        #endregion

        #region Private Fields 
        // The original metadata collection over which this filtered collection is the view
        private readonly ReadOnlyMetadataCollection _source; 
        private readonly Predicate _predicate; 
        #endregion
 
        #region Properties

        /// 
        /// Gets an item from the collection with the given identity 
        /// 
        /// The identity of the item to search for 
        /// An item from the collection 
        /// Thrown if identity argument passed in is null
        /// Thrown if setter is called 
        public override TDerived this[string identity]
        {
            get
            { 
                TBase item = _source[identity];
                if (_predicate(item)) 
                { 
                    return (TDerived)item;
                } 
                throw EntityUtil.ItemInvalidIdentity(identity, "identity");
            }
        }
 
        #endregion
 
        #region Methods 
        /// 
        /// Gets an item from the collection with the given identity 
        /// 
        /// The identity of the item to search for
        /// Whether case is ignore in the search
        /// An item from the collection 
        /// Thrown if identity argument passed in is null
        /// Thrown if the Collection does not have an item with the given identity 
        public override TDerived GetValue(string identity, bool ignoreCase) 
        {
            TBase item = _source.GetValue(identity, ignoreCase); 

            if (_predicate(item))
            {
                return (TDerived)item; 
            }
            throw EntityUtil.ItemInvalidIdentity(identity, "identity"); 
        } 

        ///  
        /// Determines if this collection contains an item of the given identity
        /// 
        /// The identity of the item to check for
        /// True if the collection contains the item with the given identity 
        /// Thrown if identity argument passed in is null
        /// Thrown if identity argument passed in is empty string 
        public override bool Contains(string identity) 
        {
            TBase item; 
            if (_source.TryGetValue(identity, false/*ignoreCase*/, out item))
            {
                return (_predicate(item));
            } 
            return false;
        } 
 
        /// 
        /// Gets an item from the collection with the given identity 
        /// 
        /// The identity of the item to search for
        /// Whether case is ignore in the search
        /// An item from the collection, null if the item is not found 
        /// True an item is retrieved
        /// if identity argument is null 
        public override bool TryGetValue(string identity, bool ignoreCase, out TDerived item) 
        {
            item = null; 
            TBase baseTypeItem;
            if (_source.TryGetValue(identity, ignoreCase, out baseTypeItem))
            {
                if (_predicate(baseTypeItem)) 
                {
                    item = (TDerived)baseTypeItem; 
                    return true; 
                }
            } 
            return false;
        }

        internal static List FilterCollection(ReadOnlyMetadataCollection collection, Predicate predicate) 
        {
            List list = new List(collection.Count); 
            foreach (TBase item in collection) 
            {
                if (predicate(item)) 
                {
                    list.Add((TDerived)item);
                }
            } 

            return list; 
        } 

        ///  
        /// Get index of the element passed as the argument
        /// 
        /// 
        ///  
        public override int IndexOf(TDerived value)
        { 
            TBase item; 
            if (_source.TryGetValue(value.Identity, false /*ignoreCase*/, out item))
            { 
                if (_predicate(item))
                {
                    // Since we are gauranteed to have a unique identity per collection, this item must of T Type
                    return base.IndexOf((TDerived)item); 
                }
            } 
            return -1; 
        }
 
        #endregion

        #region IBaseList Members
 
        TBase IBaseList.this[string identity]
        { 
            get { return this[identity]; } 
        }
 
        TBase IBaseList.this[int index]
        {
            get
            { 
                return this[index];
            } 
        } 

        ///  
        /// Get index of the element passed as the argument
        /// 
        /// 
        ///  
        int IBaseList.IndexOf(TBase item)
        { 
            if (_predicate(item)) 
            {
                return this.IndexOf((TDerived)item); 
            }

            return -1;
        } 

        #endregion 
    } 
#pragma warning restore 1711
} 

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

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