.Net中的並行編程-7.基於BlockingCollection實現高效能非同步隊列

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　　三年前寫過基於ConcurrentQueue的非同步隊列，今天在整理代碼的時候發現當時另外一種實現方式－使用BlockingCollection實現，這種方式目前依然在實際項目中使用。關於BlockingCollection的基本使用請查閱MSDN。源碼實現

下面直接上代碼：(代碼已經放到了我的github上)

using System;using System.Collections.Concurrent;using System.Collections.Generic;using System.Threading;using Danny.Infrastructure.Helper;namespace Danny.Infrastructure.Collections{    /// <summary>    /// 一個基於BlockingCollection實現的多線程的處理隊列    /// </summary>    public class ProcessQueue<T>    {        private  BlockingCollection<T> _queue;        private CancellationTokenSource _cancellationTokenSource;        private CancellationToken _cancellToken;        //內部線程池        private List<Thread> _threadCollection;        //隊列是否正在處理資料        private int _isProcessing;        //有線程正在處理資料        private const int Processing = 1;        //沒有線程處理資料        private const int UnProcessing = 0;        //隊列是否可用        private volatile bool _enabled = true;        //內部處理線程數量        private int _internalThreadCount;             public event Action<T> ProcessItemEvent;        //處理異常，需要三個參數，當前隊列執行個體，異常，當時處理的資料        public event Action<dynamic,Exception,T> ProcessExceptionEvent;        public ProcessQueue()        {            _queue=new BlockingCollection<T>();            _cancellationTokenSource = new CancellationTokenSource();            _internalThreadCount = 1;            _cancellToken = _cancellationTokenSource.Token;            _threadCollection = new List<Thread>();        }        public ProcessQueue(int internalThreadCount):this()        {            this._internalThreadCount = internalThreadCount;        }        /// <summary>        /// 隊列內部元素的數量         /// </summary>        public int GetInternalItemCount()        {            return _queue.Count;        }        public void Enqueue(T items)        {            if (items == null)            {                throw new ArgumentException("items");            }            _queue.Add(items);            DataAdded();        }        public void Flush()        {            StopProcess();            while (_queue.Count != 0)            {                T item=default(T);                if (_queue.TryTake(out item))                {                    try                    {                        ProcessItemEvent(item);                    }                    catch (Exception ex)                    {                        OnProcessException(ex,item);                    }                }            }        }        private void DataAdded()        {            if (_enabled)            {                if (!IsProcessingItem())                {                    ProcessRangeItem();                    StartProcess();                }            }        }        //判斷是否隊列有線程正在處理         private bool IsProcessingItem()        {            return !(Interlocked.CompareExchange(ref _isProcessing, Processing, UnProcessing) == UnProcessing);        }        private void ProcessRangeItem()        {            for (int i = 0; i < this._internalThreadCount; i++)            {                ProcessItem();            }        }        private void ProcessItem()        {            Thread currentThread = new Thread((state) =>            {                T item=default(T);                while (_enabled)                {                    try                    {                        try                        {                            item = _queue.Take(_cancellToken);                            ProcessItemEvent(item);                        }                        catch (OperationCanceledException ex)                        {                            DebugHelper.DebugView(ex.ToString());                        }                    }                    catch (Exception ex)                    {                        OnProcessException(ex,item);                    }                }            });            _threadCollection.Add(currentThread);        }        private void StartProcess()        {            foreach (var thread in _threadCollection)            {                thread.Start();            }        }        private void StopProcess()        {            this._enabled = false;            foreach (var thread in _threadCollection)            {                if (thread.IsAlive)                {                    thread.Join();                }            }            _threadCollection.Clear();        }        private void OnProcessException(Exception ex,T item)        {            var tempException = ProcessExceptionEvent;            Interlocked.CompareExchange(ref ProcessExceptionEvent, null, null);            if (tempException != null)            {                ProcessExceptionEvent(this,ex,item);            }        }    }}

使用方法：

class Program    {        static void Main(string[] args)        {            ProcessQueue<int> processQueue = new ProcessQueue<int>();            processQueue.ProcessExceptionEvent += ProcessQueue_ProcessExceptionEvent;            processQueue.ProcessItemEvent += ProcessQueue_ProcessItemEvent;            processQueue.Enqueue(1);            processQueue.Enqueue(2);            processQueue.Enqueue(3);        }        /// <summary>        /// 該方法對入隊的每個元素進行處理        /// </summary>        /// <param name="value"></param>        private static void ProcessQueue_ProcessItemEvent(int value)        {            Console.WriteLine(value);        }        /// <summary>        ///  處理異常        /// </summary>        /// <param name="obj">隊列執行個體</param>        /// <param name="ex">異常對象</param>        /// <param name="value">出錯的資料</param>        private static void ProcessQueue_ProcessExceptionEvent(dynamic obj, Exception ex, int value)        {            Console.WriteLine(ex.ToString());        }    }

 

.Net中的並行編程-7.基於BlockingCollection實現高效能非同步隊列