1 files changed, 96 insertions, 0 deletions
diff --git a/src/core/Support/GeneralKeyedCollection.cs b/src/core/Support/GeneralKeyedCollection.cs
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+++ b/src/core/Support/GeneralKeyedCollection.cs
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+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+*/
+
+using System;
+using System.Diagnostics;
+
+namespace Lucene.Net.Support
+{
+    /// <summary>A collection of <typeparamref name="TItem"/> which can be
+    /// looked up by instances of <typeparamref name="TKey"/>.</summary>
+    /// <typeparam name="TItem">The type of the items contains in this
+    /// collection.</typeparam>
+    /// <typeparam name="TKey">The type of the keys that can be used to look
+    /// up the items.</typeparam>
+    internal class GeneralKeyedCollection<TKey, TItem> : System.Collections.ObjectModel.KeyedCollection<TKey, TItem>
+    {
+        /// <summary>Creates a new instance of the
+        /// <see cref="GeneralKeyedCollection{TKey, TItem}"/> class.</summary>
+        /// <param name="converter">The <see cref="Converter{TInput, TOutput}"/> which will convert
+        /// instances of <typeparamref name="TItem"/> to <typeparamref name="TKey"/>
+        /// when the override of <see cref="GetKeyForItem(TItem)"/> is called.</param>
+        internal GeneralKeyedCollection(Converter<TItem, TKey> converter)
+            : base()
+        {
+            // If the converter is null, throw an exception.
+            if (converter == null) throw new ArgumentNullException("converter");
+
+            // Store the converter.
+            this.converter = converter;
+
+            // That's all folks.
+            return;
+        }
+
+        /// <summary>The <see cref="Converter{TInput, TOutput}"/> which will convert
+        /// instances of <typeparamref name="TItem"/> to <typeparamref name="TKey"/>
+        /// when the override of <see cref="GetKeyForItem(TItem)"/> is called.</summary>
+        private readonly Converter<TItem, TKey> converter;
+
+        /// <summary>Converts an item that is added to the collection to
+        /// a key.</summary>
+        /// <param name="item">The instance of <typeparamref name="TItem"/>
+        /// to convert into an instance of <typeparamref name="TKey"/>.</param>
+        /// <returns>The instance of <typeparamref name="TKey"/> which is the
+        /// key for this item.</returns>
+        protected override TKey GetKeyForItem(TItem item)
+        {
+            // The converter is not null.
+            Debug.Assert(converter != null);
+
+            // Call the converter.
+            return converter(item);
+        }
+
+        /// <summary>Determines if a key for an item exists in this
+        /// collection.</summary>
+        /// <param name="key">The instance of <typeparamref name="TKey"/>
+        /// to see if it exists in this collection.</param>
+        /// <returns>True if the key exists in the collection, false otherwise.</returns>
+        public bool ContainsKey(TKey key)
+        {
+            // Call the dictionary - it is lazily created when the first item is added
+            if (Dictionary != null)
+            {
+                return Dictionary.ContainsKey(key);
+            }
+            else
+            {
+                return false;
+            }
+        }
+
+        public System.Collections.Generic.IList<TItem> Values()
+        {
+            return base.Items;
+        }
+    }
+}