samplethread.cs

C#高级编程第6版随书源代码 值得下载

using System;
using System.Diagnostics;
using System.Threading;

namespace Wrox.ProCSharp.Threading
{

   public class StateObject
   {
      private int state = 5;
      private object sync = new object();

      public void ChangeState(int loop)
      {
         lock (sync)
         {
            if (state == 5)
            {
               state++;
               Trace.Assert(state == 6, "Race condition occurred after " + loop + " loops");
            }
            state = 5;
         }
      }
   }

   public class SampleThread
   {
      //internal static int a;
      //private static Object sync = new object();

      public SampleThread()
      {

      }

      public void RaceCondition(object o)
      {
         Trace.Assert(o is StateObject, "o must be of type StateObject");
         StateObject state = o as StateObject;

         int i = 0;
         while (true)
         {
           // lock (state) // no race condition with this lock
            {
               state.ChangeState(i++);
            }
         }
        
      }

      public SampleThread(StateObject s1, StateObject s2)
      {
         this.s1 = s1;
         this.s2 = s2;
      }

      StateObject s1;
      StateObject s2;
     

      public void Deadlock1()
      {
         int i = 0;
         while (true)
         {
            lock (s1)
            {
               lock (s2)
               {
                  s1.ChangeState(i);
                  s2.ChangeState(i++);
                  Console.WriteLine("still running, {0}", i);
               }
            }
         }

      }

      public void Deadlock2()
      {
         int i = 0;
         while (true)
         {
            lock (s2)
            {
               lock (s1)
               {
                  s1.ChangeState(i);
                  s2.ChangeState(i++);
                  Console.WriteLine("still running, {0}", i);
               }
            }
         }
      }

   }
}