1 files changed, 141 insertions, 0 deletions

diff --git a/src/core/Util/Cache/SimpleMapCache.cs b/src/core/Util/Cache/SimpleMapCache.cs
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+++ b/src/core/Util/Cache/SimpleMapCache.cs
@@ -0,0 +1,141 @@
+/* 
+ * 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.Collections.Generic;
+
+namespace Lucene.Net.Util.Cache
+{
+	
+	/// <summary> Simple cache implementation that uses a HashMap to store (key, value) pairs.
+    /// This cache is not synchronized, use <see cref="Cache{TKey, TValue}.SynchronizedCache(Cache{TKey, TValue})" />
+	/// if needed.
+	/// </summary>
+	public class SimpleMapCache<TKey, TValue> : Cache<TKey, TValue>
+	{
+		internal System.Collections.Generic.Dictionary<TKey, TValue> map;
+
+        public SimpleMapCache()
+            : this(new System.Collections.Generic.Dictionary<TKey, TValue>())
+		{
+		}
+
+        public SimpleMapCache(System.Collections.Generic.Dictionary<TKey, TValue> map)
+		{
+			this.map = map;
+		}
+		
+		public override TValue Get(System.Object key)
+		{
+			return map[(TKey)key];
+		}
+		
+		public override void  Put(TKey key, TValue value_Renamed)
+		{
+			map[key] = value_Renamed;
+		}
+		
+		public override bool ContainsKey(System.Object key)
+		{
+			return map.ContainsKey((TKey)key);
+		}
+
+	    protected override void Dispose(bool disposing)
+	    {
+	        // do nothing
+	    }
+
+	    /// <summary> Returns a Set containing all keys in this cache.</summary>
+		public virtual System.Collections.Generic.HashSet<TKey> KeySet()
+		{
+			return new HashSet<TKey>(map.Keys);
+		}
+		
+		internal override Cache<TKey, TValue> GetSynchronizedCache()
+		{
+			return new SynchronizedSimpleMapCache(this);
+		}
+		
+        // Why does does this use both inheritance and composition?
+		private class SynchronizedSimpleMapCache : SimpleMapCache<TKey, TValue>
+		{
+			private System.Object mutex;
+            private SimpleMapCache<TKey, TValue> cache;
+
+		    private bool isDisposed;
+
+            internal SynchronizedSimpleMapCache(SimpleMapCache<TKey, TValue> cache)
+			{
+				this.cache = cache;
+				this.mutex = this;
+			}
+			
+			public override void  Put(TKey key, TValue value_Renamed)
+			{
+				lock (mutex)
+				{
+					cache.Put(key, value_Renamed);
+				}
+			}
+			
+			public override TValue Get(System.Object key)
+			{
+				lock (mutex)
+				{
+					return cache.Get(key);
+				}
+			}
+			
+			public override bool ContainsKey(System.Object key)
+			{
+				lock (mutex)
+				{
+					return cache.ContainsKey(key);
+				}
+			}
+			
+			protected override void Dispose(bool disposing)
+			{
+				lock (mutex)
+				{
+                    if (isDisposed) return;
+
+                    if (disposing)
+                    {
+                        cache.Dispose(disposing);
+                    }
+
+                    isDisposed = true;
+                    base.Dispose(disposing);
+				}
+			}
+			
+			public override HashSet<TKey> KeySet()
+			{
+				lock (mutex)
+				{
+					return cache.KeySet();
+				}
+			}
+			
+			internal override Cache<TKey, TValue> GetSynchronizedCache()
+			{
+				return this;
+			}
+		}
+	}
+}
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