Singleton mode, Mode

Singleton mode, Mode

1 // 1. Thread unsafe 2 // public sealed class Singleton 3 // {4 // private static Singleton instance; // define a private static global variable to save the unique instance of the modified class 5 // private Singleton () {}6 // public static Singleton GetInstance () 7 // {8 /// if the class is not instantiated, create and modify instance 9 // return instance ?? (Instance = new Singleton ()); 10 //} 11 //} 12 13 14 // 2. thread security 15 // public sealed class Singleton16 // {17 // private static Singleton instance = null; 18 //// create a static read-only process auxiliary object 19 // private static readonly object _ lock = new object (); 20 // Singleton () {} 21 // public static Singleton GetInstance () 22 // {23 // lock (_ lock) 24 // {25 // return instance ?? (Instance = new Singleton ()); 26 //} 27 //} 28 //} 29 30 31 32 // 3. thread security double lock 33 // public sealed class Singleton34 // {35 // private static Singleton instance; 36 // private static object _ lock = new object (); 37 // private Singleton () {}38 // public static Singleton GetInstance () 39 // {40 // if (instance = null) // when the instance is null, lock creation 41 // {42 // lock (_ lock) // ensure that only one thread can access the modified statement block 43 // {44 // instance = instance ?? (New Singleton (); 45 //} 46 //} 47 // return instance; 48 //} 49 //} 50 51 52 53 54 // 4. Thread Security static initialization 55 // public sealed class Singleton56 // {57 // private static Singleton instance = new singleton (); 58 // private Singleton () {}59 // public static Singleton GetInstance () 60 // {61 // return instance; 62 //} 63 //} 64 65 66 // 5. Delayed initialization, internal class 67 // public sealed class Singleton68 // {69 // private Singleton () {} 70 // public static Singleton GetInstance () 71 // {72 // return Nested. instance; 73 //} 74 // The initialization work is put into the static member of the Nested class to complete 75 // private class Nested76 // {77 // static Nested () {} 78 // internal static readonly Singleton instance = new Singleton (); 79 //} 80 //} 81 82 83 // 6. Delayed initialization, thread security 84 public sealed class Singleton85 {86 private static readonly Lazy <Singleton> lazy = new Lazy <Singleton> () => new Singleton ()); 87 public static Singleton GetInstance () 88 {89 return lazy. value; 90} 91 private Singleton () {}92}