/// <summary>
    /// 本例利用VolatileWrite和VolatileRead來(lái)實(shí)現(xiàn)同步,，來(lái)實(shí)現(xiàn)一個(gè)計(jì)算
    /// 的例子，每個(gè)線(xiàn)程負(fù)責(zé)運(yùn)算1000萬(wàn)個(gè)數(shù)據(jù),，共開(kāi)啟10個(gè)線(xiàn)程計(jì)算至1億,，
    /// 而且每個(gè)線(xiàn)程都無(wú)法干擾其他線(xiàn)程工作
    /// </summary>
    class Program
    {
        static Int32 count;//計(jì)數(shù)值，用于線(xiàn)程同步 （注意原子性,，所以本例中使用int32）
        static Int32 value;//實(shí)際運(yùn)算值,，用于顯示計(jì)算結(jié)果
        static void Main(string[] args)
        {
            //開(kāi)辟一個(gè)線(xiàn)程專(zhuān)門(mén)負(fù)責(zé)讀value的值，這樣就能看見(jiàn)一個(gè)計(jì)算的過(guò)程
            Thread thread2 = new Thread(new ThreadStart(Read));
            thread2.Start();
            //開(kāi)辟10個(gè)線(xiàn)程來(lái)負(fù)責(zé)計(jì)算,，每個(gè)線(xiàn)程負(fù)責(zé)1000萬(wàn)條數(shù)據(jù)
            for (int i = 0; i < 10; i++)
            {
                Thread.Sleep(20);
                Thread thread = new Thread(new ThreadStart(Write));
                thread.Start();
            }
            Console.ReadKey();
        }

        /// <summary>
        /// 實(shí)際運(yùn)算寫(xiě)操作
        /// </summary>
        private static void Write()
        {
            Int32 temp = 0;
            for (int i = 0; i < 10000000; i++)
            {
                temp += 1;
            }
            value += temp;
            //注意VolatileWrite 在每個(gè)線(xiàn)程計(jì)算完畢時(shí)會(huì)寫(xiě)入同步計(jì)數(shù)值為1,，告訴程序該線(xiàn)程已經(jīng)執(zhí)行完畢
            //所以VolatileWrite方法類(lèi)似與一個(gè)按鈴，往往在原子性的最后寫(xiě)入告訴程序我完成了
            Thread.VolatileWrite(ref count, 1);
        }

        /// <summary>
        ///  顯示計(jì)算后的數(shù)據(jù),，使用該方法的線(xiàn)程會(huì)死循環(huán)等待寫(xiě)
        ///  操作的線(xiàn)程發(fā)出完畢信號(hào)后顯示當(dāng)前計(jì)算結(jié)果
        /// </summary>
        private static void Read()
        {
            while (true)
            {
                //一旦監(jiān)聽(tīng)到一個(gè)寫(xiě)操作線(xiàn)執(zhí)行完畢后立刻顯示操作結(jié)果
                //和VolatileWrite相反,，VolatileRead類(lèi)似一個(gè)門(mén)禁，只有原子性的最先讀取他,，才能達(dá)到同步效果
                //同時(shí)count值保持最新
                if (Thread.VolatileRead(ref count) > 0)
                {
                    Console.WriteLine("累計(jì)計(jì)數(shù):{1}", Thread.CurrentThread.ManagedThreadId, value);
                    //將count設(shè)置成0,，等待另一個(gè)線(xiàn)程執(zhí)行完畢
                    count = 0;
                }
            }
        }


    }

  /// <summary>
    /// 本示例通過(guò)Interlocked實(shí)現(xiàn)同步示例,，通過(guò)Interlocked.Increment和
    /// Interlocked.Decrement來(lái)實(shí)現(xiàn)同步，此例有2個(gè)共享區(qū),，一個(gè)必須滿(mǎn)足計(jì)數(shù)值為0,，另
    /// 一個(gè)滿(mǎn)足計(jì)數(shù)值為1時(shí)才能進(jìn)入
    /// </summary>
    class Program
    {
        //聲明計(jì)數(shù)變量
        //（注意這里用的是long是64位的，所以在32位機(jī)子上一定要通過(guò)Interlocked來(lái)實(shí)現(xiàn)原子操作）
        static long _count = 0;

        static void Main(string[] args)
        {
            //開(kāi)啟6個(gè)線(xiàn)程,，3個(gè)執(zhí)行Excution1,，三個(gè)執(zhí)行Excution2
            for (int i = 0; i < 3; i++)
            {
                Thread thread = new Thread(new ThreadStart(Excution1));
                Thread thread2 = new Thread(new ThreadStart(Excution2));
                thread.Start();
                Thread.Sleep(10);
                thread2.Start();
                Thread.Sleep(10);
            }
            //這里和同步無(wú)關(guān)，只是簡(jiǎn)單的對(duì)Interlocked方法進(jìn)行示例
            Interlocked.Add(ref _count, 2);
            Console.WriteLine("為當(dāng)前計(jì)數(shù)值加上一個(gè)數(shù)量級(jí):{0}后,，當(dāng)前計(jì)數(shù)值為:{1}", 2, _count);
            Interlocked.Exchange(ref _count, 1);
            Console.WriteLine("將當(dāng)前計(jì)數(shù)值改變后,，當(dāng)前計(jì)數(shù)值為:{0}", _count);
            Console.Read();
        }

        static void Excution1()
        {
            //進(jìn)入共享區(qū)1的條件
            if (Interlocked.Read(ref _count) == 0)
            {
                Console.WriteLine("Thread ID:{0} 進(jìn)入了共享區(qū)1", Thread.CurrentThread.ManagedThreadId);
                //原子性增加計(jì)數(shù)值，讓其他線(xiàn)程進(jìn)入共享區(qū)2
                Interlocked.Increment(ref _count);
                Console.WriteLine("此時(shí)計(jì)數(shù)值Count為:{0}", Interlocked.Read(ref _count));
            }
        }

        static void Excution2()
        {
            //進(jìn)入共享區(qū)2的條件
            if (Interlocked.Read(ref _count) == 1)
            {
                Console.WriteLine("Thread ID:{0} 進(jìn)入了共享區(qū)2", Thread.CurrentThread.ManagedThreadId);
                //原子性減少計(jì)數(shù)值,，讓其他線(xiàn)程進(jìn)入共享區(qū)1
                Interlocked.Decrement(ref _count);
                Console.WriteLine("此時(shí)計(jì)數(shù)值Count為:{0}", Interlocked.Read(ref _count));
            }
        }
    }

    /// <summary>
    /// 本例展示下如何使用lock關(guān)鍵字和lock(this)時(shí)產(chǎn)生死鎖的情況
    /// </summary>
    class Program
    {

        static void Main(string[] args)
        {
            //創(chuàng)建b對(duì)象，演示lock
            B b = new B();
            Console.ReadKey();
        }
    }

    /// <summary>
    /// A類(lèi)構(gòu)造中初始化一個(gè)線(xiàn)程并且啟動(dòng),，
    /// 線(xiàn)程調(diào)用的方法內(nèi)放入死循環(huán),，并且在死循環(huán)中放入lock(this)，
    /// </summary>
    public class A
    {
        public A()
        {
            Thread th = new Thread(new ThreadStart
                (
                   () =>
                   {
                       while (true)
                       {
                           lock (this)
                           {
                               Console.WriteLine("進(jìn)入a類(lèi)共享區(qū)");
                               Thread.Sleep(3000);
                           }
                       }
                   }
                ));
            th.Start();
        }
    }

    /// <summary>
    ///  B類(lèi)在構(gòu)造中創(chuàng)建A的對(duì)象,，并且還是鎖住a對(duì)象,，這樣就創(chuàng)建的死鎖的條件
    ///  因?yàn)槌跏蓟疉類(lèi)對(duì)象時(shí)，A類(lèi)的構(gòu)造函數(shù)會(huì)鎖住自身對(duì)象,，這樣在A類(lèi)死循環(huán)間隔期,，一旦出了 A類(lèi)中的鎖時(shí)
    ///  進(jìn)入B的鎖住的區(qū)域內(nèi),，A 對(duì)象永遠(yuǎn)無(wú)法進(jìn)入a類(lèi)共享區(qū)，從而產(chǎn)生了死鎖
    /// </summary>
    public class B
    {
        public B()
        {
            A a = new A();
            lock (a)
            {
                Console.WriteLine(@"將a類(lèi)對(duì)象鎖住的話(huà),，a類(lèi)中的lock將進(jìn)入死鎖,，
                直到3秒后B類(lèi)中的將a類(lèi)對(duì)象釋放鎖,如果我不釋放，那么 a類(lèi)中將永遠(yuǎn)無(wú)法進(jìn)入a類(lèi)共享區(qū)");
                //計(jì)時(shí)器
                Timer timer = new Timer(new TimerCallback
                    (
                      (obj) => { Console.WriteLine(DateTime.Now); }
                    ), this, 0, 1000);
                //如果這里運(yùn)行很長(zhǎng)時(shí)間,， a類(lèi)中將永遠(yuǎn)無(wú)法進(jìn)入a類(lèi)共享區(qū)
                Thread.Sleep(3000000);
            }
        }
    }

    /// <summary>
    /// 該示例通過(guò)ReaderWriterLock同步來(lái)實(shí)現(xiàn)Student集合多線(xiàn)程下
    /// 的寫(xiě)操作和讀操作
    /// </summary>
    class Program
    {
        static ReaderWriterLock _readAndWriteLock = new ReaderWriterLock();
        static List<Student> demoList = new List<Student>();

        static void Main(string[] args)
        {
            InitialStudentList();
            Thread thread=null;
            for (int i = 0; i <5; i++)
            {
              
                //讓第前2個(gè)個(gè)線(xiàn)程試圖掌控寫(xiě)鎖,
                if (i < 2)
                {
                    thread = new Thread(new ParameterizedThreadStart(AddStudent));
                    Console.WriteLine("線(xiàn)程ID:{0}, 嘗試獲取寫(xiě)鎖        ", thread.ManagedThreadId);
                    thread.Start(new Student { Name = "Zhang" + i });
                }
                else 
                {
                    //讓每個(gè)線(xiàn)程都能訪(fǎng)問(wèn)DisplayStudent 方法去獲取讀鎖
                    thread = new Thread(new ThreadStart(DisplayStudent));
                    thread.Start();
                }
                Thread.Sleep(20);
            }
            Console.ReadKey();
        }

        static void InitialStudentList() 
        {
            demoList = new List<Student> { new Student{ Name="Sun"}, new Student{Name="Zheng"} };
        }

        /// <summary>
        /// 當(dāng)多個(gè)線(xiàn)程試圖使用該方法時(shí)，只有一個(gè)線(xiàn)程能夠透過(guò)AcquireSWriterLock
        /// 獲取寫(xiě)鎖,，同時(shí)其他線(xiàn)程進(jìn)入隊(duì)列中等待,，直到該線(xiàn)程使用ReleaseWriterLock后
        /// 下個(gè)線(xiàn)程才能進(jìn)入擁有寫(xiě)鎖
        /// </summary>
        /// <param name="student"></param>
        static void AddStudent(object student)
        {
            if (student == null|| !(student is Student)) return;
            if (demoList.Contains(student)) return;
            try
            {
                //獲取寫(xiě)鎖
                _readAndWriteLock.AcquireWriterLock(Timeout.Infinite);
                demoList.Add(student as Student);
                Console.WriteLine("當(dāng)前寫(xiě)操作線(xiàn)程為{0},            寫(xiě)入的學(xué)生是：{1}", Thread.CurrentThread.ManagedThreadId,(student as Student).Name);
            }
            catch (Exception)
            {

            }
            finally
            {
                _readAndWriteLock.ReleaseWriterLock();
            }

        }

        /// <summary>
        /// 對(duì)于讀鎖來(lái)所，允許多個(gè)線(xiàn)程共同擁有,，所以這里同時(shí)
        /// 可能會(huì)有多個(gè)線(xiàn)程訪(fǎng)問(wèn)Student集合,，使用try catch是為了
        /// 一定要讓程序執(zhí)行finally語(yǔ)句塊中的releaseXXX方法，從而保證
        /// 能夠釋放鎖
        /// </summary>
        static void DisplayStudent()
        {
            try
            {
                _readAndWriteLock.AcquireReaderLock(Timeout.Infinite);
                demoList.ForEach(student
                  =>
                {
                    Console.WriteLine("當(dāng)前集合中學(xué)生為:{0},當(dāng)前讀操作線(xiàn)程為{1}", student.Name, Thread.CurrentThread.ManagedThreadId);
                });
            }
            catch (Exception)
            {
              
            }
            finally
            {
                _readAndWriteLock.ReleaseReaderLock();
            }
        }

    }

    internal class Student
    {
        public string Name { get; set; }
    }