[C#]『Barrier』任务并行库使用小计

Barrier  是一个对象，它可以在并行操作中的所有任务都达到相应的关卡之前，阻止各个任务继续执行。 如果并行操作是分阶段执行的，并且每一阶段要求各任务之间进行同步，则可以使用该对象。 ——MSDN

按照我的理解Barrier其实就是将多个任务同步，而同步需要一个屏障或者是关卡，那么其方法SignalAndWait()就是屏障的作用；

我们来模拟现实中例子，做火车就是很好的参照，大家知道，火车的车次有个发车点，到了那个时间点才能发车，那我们稍微修改下，人到齐后才能发车。

1.首先从家出发，在路上实现：

        private static void OnRoading(string name, int costTime)
        {
            Console.WriteLine(string.Format("[{0}]在去火车站路上.....,花费{1}小时.", name, costTime));
            Thread.Sleep(new TimeSpan(0, 0, costTime));
        }

2.达到火车站，等候火车，这相当于同步任务，（所模拟的是，乘火车到人到齐后才能发车）

        private static void OnStationing(string name)
        {
            Console.WriteLine(string.Format("[{0}]到达火车站，正在安检等候火车.....", name));
            gate.SignalAndWait();
        }

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3.人到齐后，发车

        private static void OnTraining(string name)
        {
            Console.WriteLine(string.Format("[{0}]乘坐火车离开.....", name));
        }

完整代码实现

        static Barrier gate;
        static void Main(string[] args)
        {
            try
            {
                ToStationWorkTyp2();
            }
            catch (Exception ex)
            {
                Console.WriteLine(string.Format("Exception Message:{0}", ex.Message.Trim()));
            }
            finally
            {
                Console.ReadLine();
            }
        }
        private static void ToStationWorkTyp2()
        {
            gate = new Barrier(3);
            Task _taskA = Task.Factory.StartNew(() =>
            {
                OnRoading("personA", 2);
                OnStationing("personA");
                OnTraining("personA");
            });

            Task _taskB = Task.Factory.StartNew(() =>
            {
                OnRoading("personB", 5);
                OnStationing("personB");
                OnTraining("personB");
            });

            Task _taskC = Task.Factory.StartNew(() =>
            {
                OnRoading("personC", 3);
                OnStationing("personC");
                OnTraining("personC");
            });
            Task.WaitAll(_taskA, _taskB, _taskC);

        }
        private static void OnTraining(string name)
        {
            Console.WriteLine(string.Format("[{0}]乘坐火车离开.....", name));
        }
        private static void OnStationing(string name)
        {
            Console.WriteLine(string.Format("[{0}]到达火车站，正在安检等候火车.....", name));
            gate.SignalAndWait();
        }
        private static void OnRoading(string name, int costTime)
        {
            Console.WriteLine(string.Format("[{0}]在去火车站路上.....,花费{1}小时.", name, costTime));
            Thread.Sleep(new TimeSpan(0, 0, costTime));
        }

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.csharpcode .lnum { color: #606060; }代码效果

另外一种代码实现

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace PLinq
{
    class Program
    {
        static Barrier gate;
        static void Main(string[] args)
        {
            try
            {
                ToStationWorkTyp1();
            }
            catch (Exception ex)
            {
                Console.WriteLine(string.Format("Exception Message:{0}", ex.Message.Trim()));
            }
            finally
            {
                Console.ReadLine();
            }
        }
        private static void ToStationWorkTyp1()
        {
            gate = new Barrier(3);
            Task _taskA = Task.Factory.StartNew(() => ToStation("PersonA", 2));
            Task _taskB = Task.Factory.StartNew(() => ToStation("PersonB", 3));
            Task _taskC = Task.Factory.StartNew(() => ToStation("PersonC", 5));
            Task.WaitAll(_taskA, _taskB, _taskC);
        }
        private static void ToStation(string name, int costTime)
        {
            Console.WriteLine(string.Format("[{0}]在去火车站路上.....,花费{1}小时.", name, costTime));
            Thread.Sleep(new TimeSpan(0, 0, costTime));
            Console.WriteLine(string.Format("[{0}]到达火车站，正在安检等候火车.....", name));
            gate.SignalAndWait();
            Console.WriteLine(string.Format("[{0}]乘坐火车离开.....", name));
        }
    }
}

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.csharpcode .lnum { color: #606060; }同样的实现效果