fork download 
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4. using System.Text;
  5. using System.Threading.Tasks;
  6.  
  7. namespace DynamicCheckForFactory
  8. {
  9.     interface ISomething
  10.     {
  11.     }
  12.  
  13.     static class SomethingChecker
  14.     {
  15.         public static Func<T> CheckAndGetBuider<T>() where T : ISomething
  16.         {
  17.             var type = typeof(T);
  18.             var builder = type.GetMethod("GetInstance",
  19.                         System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Static);
  20.             if (builder == null)
  21.                 throw new Exception();
  22.             return () => (T)builder.Invoke(null, null);
  23.         }
  24.     }
  25.  
  26.     class GoodSomething : ISomething
  27.     {
  28.         static public GoodSomething GetInstance()
  29.         {
  30.             return new GoodSomething();
  31.         }
  32.     }
  33.  
  34.     class BadSomething : ISomething
  35.     {
  36.     }
  37.  
  38.     class Program
  39.     {
  40.         static void Main(string[] args)
  41.         {
  42.             try
  43.             {
  44.                 var goodBuilder = SomethingChecker.CheckAndGetBuider<GoodSomething>();
  45.                 var goodInstance = goodBuilder();
  46.                 Console.WriteLine("good instance obtained");
  47.             }
  48.             catch
  49.             {
  50.                 Console.WriteLine("cannot obtain good instance");
  51.             }
  52.  
  53.             try
  54.             {
  55.                 var badBuilder = SomethingChecker.CheckAndGetBuider<BadSomething>();
  56.                 var badInstance = badBuilder();
  57.                 Console.WriteLine("bad instance obtained");
  58.             }
  59.             catch
  60.             {
  61.                 Console.WriteLine("cannot obtain bad instance");
  62.             }
  63.         }
  64.     }
  65. }
  66.  
Success #stdin #stdout 0.03s 24208KB
comments (?)
stdin 
Standard input is empty
stdout 
good instance obtained
cannot obtain bad instance
https://ideone.com/bPyoEf
language:
C# (gmcs 5.20.1)
created:
10 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!