1using System;
 2using System.Collections.Generic;
 3using System.Linq;
 4
 5namespace gorilla.commons.utility
 6{
 7    public static class RegistryExtensions
 8    {
 9        public static K find_an_implementation_of<T, K>(this Registry<T> registry) where K : T
10        {
11            try
12            {
13                return registry
14                    .all()
15                    .Single(p => p.is_an_implementation_of<K>())
16                    .downcast_to<K>();
17            }
18            catch (Exception exception)
19            {
20                throw new Exception("Could Not Find an implementation of".format(typeof (K)), exception);
21            }
22        }
23
24        public static IEnumerable<T> sort_all_using<T>(this Registry<T> registry, IComparer<T> comparer)
25        {
26            return registry.all().sorted_using(comparer);
27        }
28    }
29}