1using System;
 2
 3namespace gorilla.commons.utility
 4{
 5    static public class FuncExtensions
 6    {
 7        static public readonly object mutex = new object();
 8
 9        static public Func<T> memorize<T>(this Func<T> item) where T : class
10        {
11            T the_implementation = null;
12            return () =>
13            {
14                if (null == the_implementation)
15                {
16                    lock (mutex)
17                    {
18                        if (null == the_implementation)
19                        {
20                            the_implementation = item();
21                        }
22                    }
23                }
24                return the_implementation;
25            };
26        }
27    }
28}