using System;

using System.Collections.Generic;

namespace ModuleManager.Collections

{

public class KeyValueCache<TKey, TValue>

{

private readonly Dictionary<TKey, TValue> dict = new Dictionary<TKey, TValue>();

private readonly object lockObject = new object();

public TValue Fetch(TKey key, Func<TValue> createValue)

{

if (createValue == null) throw new ArgumentNullException(nameof(createValue));

lock(lockObject)

{

if (dict.TryGetValue(key, out TValue value))

{

return value;

}

else

{

TValue newValue = createValue();

dict.Add(key, newValue);

return newValue;

}

}

}

}

}