Question

I need to create a single class instance in web application that manage a queue of process. This class have multiple thread inside that look for queue and consume it.
What is the best why to do this?

I have apply singleton design pattern, but I don’t understand if have to create static or normal queue inside it. Some one can give me an example please?

SOLUTION

Ok thank you! This is my singleton class:

    public sealed class MyWorkingSingletonClass
    {

    private static readonly ILog LOG = LogManager.GetLogger(typeof(MyWorkingSingletonClass));
    private static MyWorkingSingletonClass instanza;
    private static readonly object lockObject = new object();
    private static ConcurrentQueue<Process> syncCoda = new ConcurrentQueue<Process>();

    private MyWorkingSingletonClass()
    {
    }

    public static MyWorkingSingletonClass Instanza
    {
        get
        {
            lock (lockObject)
            {
                if (instanza == null)
                    instanza = new PdfDucumentConverter();
                return instanza;
            }
        }
    }



    public void AddProcess(Process p)
    {
        syncCoda.Enqueue(p);
    }

    public void Start()
    {
        Task.Factory.StartNew(WorkerTask2);
    }

    public static void WorkerTask2()
    {

        do
        {
            try
            {
                Process p;
                if (syncCoda.TryDequeue(out p))
                {
                    p.Start();
                    p.PriorityClass = ProcessPriorityClass.High;
                    p.WaitForExit();
                }
            }
            catch (Exception ex)
            {
                LOG.Error(ex);
            }
        } while (true);
    }

    }

Answer 1

What you need is to implement new singleton class which inherits Concurrent Queue class which is thread-safe queue to ensure it will work in multi-thread environment:

public class SingletonConcurrentQueue<T> : ConcurrentQueue<T>
{
    private static readonly SingletonConcurrentQueue<T> 
                                   _instance = new SingletonConcurrentQueue<T>();

    static SingletonConcurrentQueue(){}
    private SingletonConcurrentQueue(){}

    public static SingletonConcurrentQueue<T> Instance
    {
        get { return _instance; }
    }
}