RaspberryIO/Unosquare.Swan.Lite/Components/CollectionCacheRepository.cs
2019-12-04 17:10:06 +01:00

43 lines
1.7 KiB
C#

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
namespace Unosquare.Swan.Components {
/// <summary>
/// A thread-safe collection cache repository for types.
/// </summary>
/// <typeparam name="TValue">The type of member to cache.</typeparam>
public class CollectionCacheRepository<TValue> {
private readonly Lazy<ConcurrentDictionary<Type, IEnumerable<TValue>>> _data =
new Lazy<ConcurrentDictionary<Type, IEnumerable<TValue>>>(() =>
new ConcurrentDictionary<Type, IEnumerable<TValue>>(), true);
/// <summary>
/// Determines whether the cache contains the specified key.
/// </summary>
/// <param name="key">The key.</param>
/// <returns><c>true</c> if the cache contains the key, otherwise <c>false</c>.</returns>
public Boolean ContainsKey(Type key) => this._data.Value.ContainsKey(key);
/// <summary>
/// Retrieves the properties stored for the specified type.
/// If the properties are not available, it calls the factory method to retrieve them
/// and returns them as an array of PropertyInfo.
/// </summary>
/// <param name="key">The key.</param>
/// <param name="factory">The factory.</param>
/// <returns>
/// An array of the properties stored for the specified type.
/// </returns>
/// <exception cref="System.ArgumentNullException">type.</exception>
public IEnumerable<TValue> Retrieve(Type key, Func<Type, IEnumerable<TValue>> factory) {
if(factory == null) {
throw new ArgumentNullException(nameof(factory));
}
return this._data.Value.GetOrAdd(key, k => factory.Invoke(k).Where(item => item != null));
}
}
}