JD2022-TU1/main/tools/framework/JD.Collections/KeyedList.cs

using System;
using System.Collections.Generic;
using JD.Collections.Interfaces;
using JD.Kernel.StaticHelpers;

namespace JD.Collections
{
    /// <summary>
    /// Extends system keyedcollection.
    /// </summary>
    public abstract class KeyedList<TKey, TValue> : System.Collections.ObjectModel.KeyedCollection<TKey, TValue>, IKeyedList<TKey, TValue>
    {
        protected KeyedList()
        { }

        protected KeyedList(IEqualityComparer<TKey> comparer, int dictionaryCreationThreshold)
            : base(comparer, dictionaryCreationThreshold)
        { }

        /// <summary>
        /// Returns the value if found in the collection.
        /// </summary>
        public bool TryGetValue(TKey key, out TValue result)
        {
            IDictionary<TKey, TValue> underlyingDictionary = Dictionary;

            if (underlyingDictionary != null)
            {
                return underlyingDictionary.TryGetValue(key, out result);
            }

            IEqualityComparer<TKey> comparer = Comparer;
            foreach (TValue item in this)
            {
                if (comparer.Equals(GetKeyForItem(item), key))
                {
                    result = item;
                    return true;
                }
            }

            result = default(TValue);
            return false;
        }

        public bool ContainsKey(TKey key)
        {
            return Contains(key);
        }

        /// <summary>
        /// Creates a concrete collection from a converter.
        /// </summary>
        /// <param name="getKeyForItem"></param>
        /// <returns></returns>
        public static KeyedList<TKey, TValue> Create(Converter<TValue, TKey> getKeyForItem)
        {
            return new ConcreteKeyedList(getKeyForItem);
        }

        #region Nested

        private class ConcreteKeyedList : KeyedList<TKey, TValue>
        {
            private readonly Converter<TValue, TKey> m_getKeyForItem;

            public ConcreteKeyedList(Converter<TValue, TKey> getKeyForItem)
            {
                Throw.IfNull(getKeyForItem, "getKeyForItem");

                m_getKeyForItem = getKeyForItem;
            }

            protected override TKey GetKeyForItem(TValue item)
            {
                return m_getKeyForItem(item);
            }
        }

        #endregion
    }
}