| /* |
| * 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. |
| */ |
| |
| // ReSharper disable InconsistentlySynchronizedField |
| namespace Apache.Ignite.Core.Impl.Common |
| { |
| using System; |
| using System.Collections; |
| using System.Collections.Generic; |
| using System.Diagnostics.CodeAnalysis; |
| |
| /// <summary> |
| /// Concurrent dictionary with CopyOnWrite mechanism inside. |
| /// Good for frequent reads / infrequent writes scenarios. |
| /// </summary> |
| [SuppressMessage("Microsoft.Naming", "CA1711:IdentifiersShouldNotHaveIncorrectSuffix")] |
| [SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")] |
| public class CopyOnWriteConcurrentDictionary<TKey, TValue> : IEnumerable<KeyValuePair<TKey, TValue>> |
| { |
| /** */ |
| private volatile Dictionary<TKey, TValue> _dict = new Dictionary<TKey, TValue>(); |
| |
| /// <summary> |
| /// Gets the value associated with the specified key. |
| /// </summary> |
| /// <param name="key">The key.</param> |
| /// <param name="val">The value.</param> |
| /// <returns>true if the dictionary contains an element with the specified key; otherwise, false.</returns> |
| public bool TryGetValue(TKey key, out TValue val) |
| { |
| return _dict.TryGetValue(key, out val); |
| } |
| |
| /// <summary> |
| /// Adds a key/value pair if the key does not already exist. |
| /// </summary> |
| /// <param name="key">The key.</param> |
| /// <param name="valueFactory">The function used to generate a value for the key.</param> |
| /// <returns>The value for the key.</returns> |
| [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods")] |
| public TValue GetOrAdd(TKey key, Func<TKey, TValue> valueFactory) |
| { |
| lock (this) |
| { |
| TValue res; |
| |
| if (_dict.TryGetValue(key, out res)) |
| return res; |
| |
| var dict0 = new Dictionary<TKey, TValue>(_dict); |
| |
| res = valueFactory(key); |
| |
| dict0[key] = res; |
| |
| _dict = dict0; |
| |
| return res; |
| } |
| } |
| |
| /// <summary> |
| /// Sets a value for the key unconditionally. |
| /// </summary> |
| /// <param name="key">The key.</param> |
| /// <param name="value">The value.</param> |
| [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods")] |
| public void Set(TKey key, TValue value) |
| { |
| lock (this) |
| { |
| var dict0 = new Dictionary<TKey, TValue>(_dict); |
| |
| dict0[key] = value; |
| |
| _dict = dict0; |
| } |
| } |
| |
| /// <summary> |
| /// Removes the value with the specified key. |
| /// </summary> |
| /// <param name="key">The key.</param> |
| /// <param name="val">Removed value, if any.</param> |
| public bool Remove(TKey key, out TValue val) |
| { |
| lock (this) |
| { |
| if (!_dict.TryGetValue(key, out val)) |
| { |
| return false; |
| } |
| |
| var dict0 = new Dictionary<TKey, TValue>(_dict); |
| |
| dict0.Remove(key); |
| |
| _dict = dict0; |
| |
| return true; |
| } |
| } |
| |
| /** <inheritDoc /> */ |
| public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() |
| { |
| return _dict.GetEnumerator(); |
| } |
| |
| /** <inheritDoc /> */ |
| IEnumerator IEnumerable.GetEnumerator() |
| { |
| return GetEnumerator(); |
| } |
| } |
| } |