基元使用者模式構造--互鎖構造 Interlocked 實現的非同步web請求執行個體

標籤：threading   names   ace   callback   net   pac   except   can   linq   

 

  1 using System;  2 using System.Collections.Generic;  3 using System.Linq;  4 using System.Net.Http;  5 using System.Text;  6 using System.Threading;  7 using System.Threading.Tasks;  8   9 namespace Test 10 { 11     enum CoordinationStatus 12     { 13         AllDone, 14         Cancel, 15         Timeout 16     } 17     class AsyncCoordinator 18     { 19         private int statusReported = 0; 20         private int op_count = 1; 21  22         private Action<CoordinationStatus> callback; 23         private Timer timer; 24  25         public void AboutToBegin(int num = 1) 26         { 27             Interlocked.Add(ref op_count, num); 28         } 29  30         public void JustToEnd() 31         { 32             if (Interlocked.Decrement(ref op_count) == 0) 33             { 34                 ReportStatus(CoordinationStatus.AllDone); 35             } 36         } 37  38         public void AllBegun(Action<CoordinationStatus> callback, int timeout = Timeout.Infinite) 39         { 40             this.callback = callback; 41             if (timeout != Timeout.Infinite) 42             { 43                 timer = new Timer(Expired, null, timeout, Timeout.Infinite); 44             } 45             JustToEnd(); 46         } 47  48         private void Expired(object obj) 49         { 50             ReportStatus(CoordinationStatus.Cancel); 51         } 52         public void Cancel() 53         { 54             ReportStatus(CoordinationStatus.Cancel); 55         } 56         private void ReportStatus(CoordinationStatus status) 57         { 58             if (Interlocked.Exchange(ref statusReported, 1) == 0) 59             { 60                 callback(status); 61             } 62         } 63  64  65  66     } 67  68     class MultiWebRequests 69     { 70         private AsyncCoordinator coordinator = new AsyncCoordinator(); 71  72         private Dictionary<string, object> servers = new Dictionary<string, object>(){ 73             {"http://www.baidu.com",null}, 74             {"http://www.sina.com",null}, 75             {"http://www.qq.com",null}, 76         }; 77  78         public MultiWebRequests() 79         { 80  81             var http = new HttpClient(); 82             foreach (var url in servers.Keys) 83             { 84                 //發送了一個請求 85                 coordinator.AboutToBegin(1); 86                 http.GetByteArrayAsync(url).ContinueWith(task => GetResult(url, task)); 87             } 88             //所有請求發送完畢 89             coordinator.AllBegun(AllDone, Timeout.Infinite); 90         } 91  92         private void GetResult(string server, Task<byte[]> task) 93         { 94             object res; 95             if (task.Exception != null) 96             { 97                 res = task.Exception.InnerExceptions; 98             } 99             else100             {101                 res = task.Result.Length;102             }103             servers[server] = res;104             //完成了一個請求105             coordinator.JustToEnd();106         }107 108         public void Cancel()109         {110             coordinator.Cancel();111         }112 113         private void AllDone(CoordinationStatus status)114         {115             switch (status)116             {117                 case CoordinationStatus.AllDone:118                     Console.WriteLine("allDone: ");119 120                     foreach (var item in servers)121                     {122                         Console.Write(item.Key);123                         object val = item.Value;124                         if (val is Exception)125                         {126                             Console.WriteLine("Exception: {0}",val.GetType().Name);127                         }128                         else129                         {130                             Console.WriteLine("returned  {0:N0} bytes",val);131                         }132                     }133                     break;134                 case CoordinationStatus.Cancel:135                     break;136                 case CoordinationStatus.Timeout:137                     break;138                 default:139                     break;140             }141         }142     }143 }

 

基元使用者模式構造--互鎖構造 Interlocked 實現的非同步web請求執行個體