多线程添加元素到队列中,队列根据绑定
的事件进行自动处理,可以设置WorkSequential属性来实现对队列处理的单线程(严格顺序处理)或者多线程处理(循序出队,但是
多线程处理,不保证对队列元素的处理顺利)的选择。
另外,这段程序不能输出0,所以,最后的结果是999行,不包含0,原因是if (!item.Equals(default(T))),而default(T)恰恰是0.
代码 /***********多线程的工作队列***************
* 此工作队列保证线程安全性
*
*
*
*
* *******/
namespace WorkQueue
{
using System.Collections.Generic;
using System;
using System.Threading; public delegate void UserWorkEventHandler<T>(object sender, WorkQueue<T>.EnqueueEventArgs e);
public class WorkQueue<T>
{
private bool IsWorking; //表明处理线程是否正在工作
private object lockIsWorking = new object();//对IsWorking的同步对象 private Queue<T> queue; //实际的队列
private object lockObj = new object(); //队列同步对象 /// <summary>
/// 绑定用户需要对队列中的item对象
/// 施加的操作的事件
/// </summary>
public event UserWorkEventHandler<T> UserWork; public WorkQueue(int n)
{
queue = new Queue<T>(n);
} public WorkQueue()
{
queue = new Queue<T>();
} /// <summary>
/// 谨慎使用此函数,
/// 只保证此瞬间,队列值为空
/// </summary>
/// <returns></returns>
public bool IsEmpty()
{
lock (lockObj)
{
return queue.Count == ;
}
} private bool isOneThread; /// <summary>
/// 队列处理是否需要单线程顺序执行
/// ture表示单线程处理队列的T对象
/// 默认为false,表明按照顺序出队,但是多线程处理item
/// *****注意不要频繁改变此项****
/// </summary>
public bool WorkSequential
{
get
{
return isOneThread;
}
set
{
isOneThread = value;
} } /// <summary>
/// 向工作队列添加对象,
/// 对象添加以后,如果已经绑定工作的事件
/// 会触发事件处理程序,对item对象进行处理
/// </summary>
/// <param name="item">添加到队列的对象</param>
public void EnqueueItem(T item)
{
lock (lockObj)
{
queue.Enqueue(item);
} lock (lockIsWorking)
{
if (!IsWorking)
{
IsWorking = true;
ThreadPool.QueueUserWorkItem(doUserWork);
}
} } /// <summary>
/// 处理队列中对象的函数
/// </summary>
/// <param name="o"></param>
private void doUserWork(object o)
{
try
{
T item; while (true)
{
lock (lockObj)
{
if (queue.Count > )
{
item = queue.Dequeue();
}
else
{
return;
}
}
if (!item.Equals(default(T)))
{ if (isOneThread)
{
if (UserWork != null)
{
UserWork(this, new EnqueueEventArgs(item));
}
}
else
{
ThreadPool.QueueUserWorkItem(obj =>
{
if (UserWork != null)
{
UserWork(this, new EnqueueEventArgs(obj));
}
}, item);
} } }
}
finally
{
lock (lockIsWorking)
{
IsWorking = false;
} }
} /// <summary>
/// UserWork事件的参数,包含item对象
/// </summary>
public class EnqueueEventArgs : EventArgs
{
public T Item { get; private set; }
public EnqueueEventArgs(object item)
{
try
{
Item = (T)item;
}
catch (Exception)
{ throw new InvalidCastException("object to T 转换失败");
}
}
}
}
}
代码 using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.IO;
using WorkQueue;
namespace Program
{
class Program
{
private static List<string> list=new List<string>();
static StreamWriter sw = new StreamWriter(new FileStream("test.dat", FileMode.Create));
static void Main(string[] args)
{
WorkQueue<int> workQueue=new WorkQueue<int>();
workQueue.UserWork += new UserWorkEventHandler<int>(workQueue_UserWork);
// workQueue.WorkSequential = true;
ThreadPool.QueueUserWorkItem(o =>
{
for (int i = ; i < ; i++)
{
workQueue.EnqueueItem(i); }
});
Console.ReadLine(); list.ForEach(str=>sw.WriteLine(str));
Console.WriteLine(workQueue.IsEmpty());
sw.Close();
} static void workQueue_UserWork(object sender, WorkQueue<int>.EnqueueEventArgs e)
{ StringBuilder sb=new StringBuilder();
sb.Append(e.Item).Append("\t\t").Append(DateTime.Now.ToString("u")+"\t\t").Append(Thread.CurrentThread.ManagedThreadId);
list.Add(sb.ToString());
Thread.Sleep();
}
}
}