我正在创建一个控制台应用程序,它应该接收来自网络的消息以便处理它们。首先,我创建了一个单例类,以确保所有类都可以访问同一队列:该类为ProcessingQueue
。为什么这些辅助线程不会结束它们的执行?
public class ProcessingQueue
{
public class ItemToProcess
{
public string SourceClientId { get; set; }
public IMessage ReceivedMessage { get; set; }
}
private int m_MaxSize = 20;
private Queue<ItemToProcess> m_InternalQueue;
private static volatile ProcessingQueue m_Instance = null;
private static readonly object syncRoot = new object();
private ProcessingQueue()
{
m_InternalQueue = new Queue<ItemToProcess>();
}
public static ProcessingQueue Instance
{
get
{
if (m_Instance == null)
{
lock (syncRoot)
{
if (m_Instance == null)
{
m_Instance = new ProcessingQueue();
}
}
}
return m_Instance;
}
}
public int MaxSize
{
get
{
lock (syncRoot)
{
return m_MaxSize;
}
}
set
{
if (value > 0)
{
lock (syncRoot)
{
m_MaxSize = value;
}
}
}
}
public void Enqueue(String source, IMessage message)
{
lock (syncRoot)
{
while (m_InternalQueue.Count >= m_MaxSize)
{
Monitor.Wait(syncRoot);
}
m_InternalQueue.Enqueue(new ItemToProcess { SourceClientId = source, ReceivedMessage = message });
if (m_InternalQueue.Count == 1)
{
Monitor.PulseAll(syncRoot);
}
}
}
public ItemToProcess Dequeue()
{
lock (syncRoot)
{
while (m_InternalQueue.Count == 0)
{
Monitor.Wait(syncRoot);
}
ItemToProcess item = m_InternalQueue.Dequeue();
if (m_InternalQueue.Count == m_MaxSize - 1)
{
Monitor.PulseAll(syncRoot);
}
return item;
}
}
public int Count
{
get
{
lock (syncRoot)
{
return m_InternalQueue.Count;
}
}
}
}
然后我实现了如下项目的主要类。
- 首先,共享队列被实例化。
- 然后,我设置了一个计时器来模拟保持活动消息(第一个生产者)的到来。
- 然后我创建了消费者线程(
processing
对象)。 - 然后我创建了另一个生产者线程(
generating
对象)。 最后,我运行了所有的线程和计时器。
class程序 静态ProcessingQueue队列= ProcessingQueue.Instance; static System.Timers.Timer keep_alive_timer = new System.Timers.Timer(10000);
private static volatile bool running = true; static void Main(string[] args) { queue.MaxSize = 30; keep_alive_timer.Elapsed += new ElapsedEventHandler(delegate(object sender, ElapsedEventArgs e) { KeepAliveMessage msg = new KeepAliveMessage(Guid.NewGuid()); Console.WriteLine("Keep Alive: " + msg.MsgId); queue.Enqueue("", msg); }); keep_alive_timer.Enabled = true; keep_alive_timer.AutoReset = true; Thread processing = new Thread(delegate() { while (running) { Console.WriteLine("Number of elements in queue: {0}", queue.Count); ProcessingQueue.ItemToProcess msg = queue.Dequeue(); Console.WriteLine("Processed: msgid={0}, source={1};", msg.ReceivedMessage.MsgId, msg.SourceClientId); Thread.Sleep(1500); } }); Thread generating = new Thread(MessagesFromNetwork); processing.Start(); keep_alive_timer.Start(); generating.Start(); Console.WriteLine("RUNNING...\n"); Console.ReadLine(); running = false; keep_alive_timer.Stop(); Console.WriteLine("CLOSING...\n"); //processing.Abort(); //generating.Abort(); bool b1 = processing.Join(TimeSpan.FromSeconds(5)); bool b2 = generating.Join(TimeSpan.FromSeconds(5)); Console.WriteLine("b1 {0}", b1); Console.WriteLine("b2 {0}", b2); Console.WriteLine("END"); Console.ReadLine(); } static void MessagesFromNetwork() { string[] sourceClients = { "1", "2", "3", "4", "5" }; while (running) { IMessage msg; // interface IMessage Random random = new Random(); int type = random.Next(2); switch (type) { case 0: msg = new KeepAliveMessage(Guid.NewGuid()); // implements IMessage break; case 1: msg = new TaskMessage(Guid.NewGuid(), ...); // implements IMessage break; default: throw new Exception("Messaggio non valido!"); } Console.WriteLine("New message received: " + msg.MsgId); queue.Enqueue(sourceClients[random.Next(sourceClients.Length)], msg); Console.WriteLine("... message enqueued: " + msg.MsgId); Thread.Sleep(500); } }
}
按执行过程中输入,在running
变量为假并且两个线程应该终止。然而这并不总是会发生,事实上Join
这两种方法中的一种没有返回控制权:由于这个原因,我在Join
方法中指定了一个超时,但在Console.WriteLine("END");
之后,控制台应用程序冻结(第二个Join
返回false
)。
也许第二个线程没有正确终止......为什么?
用'懒惰'实现单身人士更容易,但我一直认为辛格尔顿是模式中最残酷的。 http://stackoverflow.com/a/1020384/14357 –
spender
好的,但我需要一个可以访问WCF服务实例的队列:在我的代码中,我模拟来自网络的数据,但实际上WCF服务的许多实例必须把数据在队列中。 – enzom83