CacheHelper.cs

namespace Caching
{
  using System;
	using System.Collections.Generic;
	using System.Web;

	public static class CacheHelper
	{
		/// <summary>
		/// Insert value into the cache using
		/// appropriate name/value pairs
		/// </summary>
		/// <typeparam name="T">Type of cached item</typeparam>
		/// <param name="o">Item to be cached</param>
		/// <param name="key">Name of item</param>
		public static void Add<T>(T o, string key)
		{
			HttpRuntime.Cache.Insert(
				key,
				o,
				null,
				DateTime.Now.AddMinutes(1d),
				System.Web.Caching.Cache.NoSlidingExpiration);
		}

		/// <summary>
		/// Remove item from cache
		/// </summary>
		/// <param name="key">Name of cached item</param>
		public static void Clear(string key)
		{
			HttpRuntime.Cache.Remove(key);
		}

		/// <summary>
		/// Check for item in cache
		/// </summary>
		/// <param name="key">Name of cached item</param>
		/// <returns></returns>
		public static bool Exists(string key)
		{
			return HttpRuntime.Cache[key] != null;
		}

		/// <summary>
		/// Retrieve cached item
		/// </summary>
		/// <typeparam name="T">Type of cached item</typeparam>
		/// <param name="key">Name of cached item</param>
		/// <param name="value">Cached value. Default(T) if
		/// item doesn't exist.</param>
		/// <returns>Cached item as type</returns>
		public static bool Get<T>(string key, out T value)
		{
			try
			{
				if (!Exists(key))
				{
					value = default(T);
					return false;
				}

				value = (T)HttpRuntime.Cache[key];
			}
			catch
			{
				value = default(T);
				return false;
			}

			return true;
		}

		/// <summary>
		/// Cache decorator
		/// </summary>
		public static class CacheProvider
		{
			public static Func<T, TResult> Decorate<T, TResult>(
				Func<T, TResult> function)
			{
				var cache = new Dictionary<T, TResult>();
				return (x) =>
				{
					if (!cache.ContainsKey(x))
					{
						cache.Add(x, function(x));
					}
					return cache[x];
				};
			}
		}
	}
}