using System;

using System.Collections;

using System.Threading;

namespace ThreadExample

{

    /// <summary>

    /// 這是用來儲存資訊的資料結構，將作為引數被傳遞

    /// </summary>

    public class SomeState

    {

        public int Cookie;

        public SomeState(int iCookie)

        {

            Cookie = iCookie;

        }

    }

    public class Alpha

    {

        public Hashtable HashCount;

        public ManualResetEvent eventX;

        public static int iCount = 0;

        public static int iMaxCount = 0;

        public Alpha(int MaxCount)

        {

            HashCount = new Hashtable(MaxCount);

            iMaxCount = MaxCount;

        }

        /// <summary>

        /// 執行緒池裡的執行緒將呼叫 Beta()方法

        /// </summary>

        /// <param name="state"></param> 

        public void Beta(Object state)

        {

            // 輸出當前執行緒的 hash 編碼值和 Cookie 的值 

            Console.WriteLine(" {0} {1} :", Thread.CurrentThread.GetHashCode(), ((SomeState)state).Cookie);

            Console.WriteLine("HashCount.Count=={0}, Thread.CurrentThread.GetHash Code()=={1}", HashCount.Count, 

                Thread.CurrentThread.GetHashCode());

            lock (HashCount)

            {

                // 如果當前的 Hash 表中沒有當前執行緒的 Hash 值，則新增之 

                if (!HashCount.ContainsKey(Thread.CurrentThread.GetHashCode()))

                    HashCount.Add(Thread.CurrentThread.GetHashCode(), 0);

                HashCount[Thread.CurrentThread.GetHashCode()] = ((int)HashCount[Thread.CurrentThread.GetHashCode()]) + 1;

            }

            Thread.Sleep(2000);

            // Interlocked.Increment() 操作是一個原子操作，具體請看下面說明 

            Interlocked.Increment(ref iCount);

            if (iCount == iMaxCount)

            {

                Console.WriteLine();

                Console.WriteLine("Setting eventX "); 

                eventX.Set();

            }

        }

    }

    public class SimplePool

    {

        public static void Main(string[] args)

        {

            Console.WriteLine("Thread Pool Sample:");

            bool W2K = false;

            // 允許執行緒池中執行最多 10 個執行緒 

            int MaxCount = 10;

            // 新建 ManualResetEvent 物件並且初始化為無訊號狀態 

            ManualResetEvent eventX = new ManualResetEvent(false);

            Console.WriteLine("Queuing {0} items to Thread Pool", MaxCount);

            // 注意初始化 oAlpha 物件的 eventX 屬性 

            Alpha oAlpha = new Alpha(MaxCount);            

            oAlpha.eventX = eventX;

            Console.WriteLine("Queue to Thread Pool 0");

            try

            {

                // 將工作項裝入執行緒池 

                // 這裡要用到 Windows 2000 以上版本才有的 API，所以可能出現 NotSupp ortException 異常 

                ThreadPool.QueueUserWorkItem(new WaitCallback(oAlpha.Beta), new SomeState(0));

                W2K = true;

            }

            catch (NotSupportedException)

            {

                Console.WriteLine("These API's may fail when called on a non-Wind ows 2000 system.");

                W2K = false;

            }

            if (W2K) // 如果當前系統支援 ThreadPool 的方法. 

            {

                for (int iItem = 1; iItem < MaxCount; iItem++)

                {

                    // 插入佇列元素 

                    Console.WriteLine("Queue to Thread Pool {0}", iItem);

                    ThreadPool.QueueUserWorkItem(new WaitCallback(oAlpha.Beta), new SomeState(iItem));

                }

                Console.WriteLine("Waiting for Thread Pool to drain");

                // 等待事件的完成，即執行緒呼叫 ManualResetEvent.Set() 方法 

                eventX.WaitOne(Timeout.Infinite, true);

                // WaitOne() 方法使呼叫它的執行緒等待直到 eventX.Set() 方法被呼叫 

                Console.WriteLine("Thread Pool has been drained (Event fired)");

                Console.WriteLine();

                Console.WriteLine("Load across threads");

                foreach (object o in oAlpha.HashCount.Keys)

                {

                    Console.WriteLine("{0} {1}", o, oAlpha.HashCount[o]);

                }

            }

            Console.ReadLine();

        }

    }

}