Demystifying concurrent lazy load pattern

using System.Collections.Generic;
using System.Threading;

namespace LazyLoadSample
{
	/// <summary>
	/// Base class for all cache implementations.
	/// </summary>
	public abstract class BaseCache
	{
		/// <summary>
		/// Gets the number of times data was loaded data loads.
		/// </summary>
		public int DataLoads { get; private set; }

		/// <summary>
		/// Gets or sets the time in milliseconds needed to load the data.
		/// </summary>
		public int TimeNeededToLoad { get; set; }

		/// <summary>
		/// Gets the products from cache.
		/// </summary>
		/// <returns>products from cache</returns>
		public abstract IList<Product> GetProducts();

		/// <summary>
		/// Resets the cache.
		/// </summary>
		public abstract void Reset();

		/// <summary>
		/// Loads the products from database.
		/// </summary>
		/// <returns>Products from database</returns>
		protected IList<Product> LoadProductsFromDatabase()
		{
			this.DataLoads++;
			Thread.Sleep(this.TimeNeededToLoad);

			// we are not going to hit a DB actually
			// to make example simpler
			IList<Product> list = new List<Product>();
			for (int i = 0; i < 10; i++)
			{
				list.Add(new Product());
			}

			return list;
		}
	}
}