110 lines
3.8 KiB
C#
110 lines
3.8 KiB
C#
/*
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* dbMango
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*
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* Copyright 2025 Deutsche Bank AG
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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using System.Collections.Concurrent;
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namespace Rms.Risk.Mango.Pivot.Core.Models;
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public class ExpiringObjectPool<TKey, TValue, TArg>
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where TValue : class
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where TKey : notnull
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{
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public static TimeSpan DefaultExpiryDuration = TimeSpan.FromHours(3);
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public static TimeSpan DefaultCleanupInterval = TimeSpan.FromMinutes(5);
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private readonly ConcurrentDictionary<TKey, (TValue Item, DateTime Expiry)> _pool;
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private readonly Func<TKey, TArg, CancellationToken, Task<TValue>> _objectGenerator;
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private readonly TimeSpan _expiryDuration;
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private readonly Timer _cleanupTimer;
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private readonly ConcurrentDictionary<TKey, Task<TValue>> _loadingTasks = new();
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public ExpiringObjectPool(Func<TKey, TArg, CancellationToken, Task<TValue>> objectGenerator, TimeSpan expiryDuration = default, TimeSpan cleanupInterval = default )
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{
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if ( cleanupInterval == TimeSpan.Zero )
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cleanupInterval = DefaultCleanupInterval;
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if (expiryDuration == TimeSpan.Zero )
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expiryDuration = DefaultExpiryDuration;
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_objectGenerator = objectGenerator ?? throw new ArgumentNullException(nameof(objectGenerator));
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_expiryDuration = expiryDuration;
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_pool = new ConcurrentDictionary<TKey, (TValue, DateTime)>();
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// Set up a timer to clean up expired objects
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_cleanupTimer = new Timer(CleanupExpiredObjects, null, cleanupInterval, cleanupInterval);
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}
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public void Clear() => _pool.Clear();
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public async Task<TValue> Get(TKey key, TArg arg, CancellationToken token = default)
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{
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if (_pool.TryGetValue(key, out var entry) && entry.Expiry > DateTime.UtcNow)
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{
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return entry.Item;
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}
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// Check if the key is already being loaded
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var loadingTask = _loadingTasks.GetOrAdd(key, _ => LoadNewItem(key, arg, token));
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try
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{
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var newItem = await loadingTask;
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return newItem;
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}
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finally
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{
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// Remove the task once loading is complete
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_loadingTasks.TryRemove(key, out _);
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}
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}
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private async Task<TValue> LoadNewItem(TKey key, TArg arg, CancellationToken token)
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{
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var newItem = await _objectGenerator(key, arg, token);
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_pool[key] = (newItem, DateTime.UtcNow.Add(_expiryDuration));
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return newItem;
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}
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public void ReturnObject(TKey key, TValue item)
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{
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if (item == null) throw new ArgumentNullException(nameof(item));
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_pool[key] = (item, DateTime.UtcNow.Add(_expiryDuration));
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}
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private void CleanupExpiredObjects(object? state)
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{
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var now = DateTime.UtcNow;
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// Remove expired objects
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var expiredKeys = _pool.Where(pair => pair.Value.Expiry <= now).Select(pair => pair.Key).ToList();
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foreach (var key in expiredKeys)
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{
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_pool.TryRemove(key, out _);
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}
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}
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public void Dispose()
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{
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_cleanupTimer.Dispose();
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}
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public void Remove(TKey key)
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{
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_pool.TryRemove(key, out _);
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}
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} |