Analogue of Queue.Peek() for BlockingCollection when listening to consuming IEnumerable

Question

I\'m using Pipelines pattern implementation to decouple messages consumer from a producer to avoid slow-consumer issue.

In case of any exception on a message processi

Answer 1

You could use ConcurrentQueue instead, it has TryDequeue() method.

ConcurrentQueue.TryDequeue(out T result) tries to remove and return the object at the beginning of the concurrent queue, it returns true if an element was removed and returned from the beginning of the ConcurrentQueue successfully.

So, no need to check a Peek first.

TryDequeue() is thread safe:

ConcurrentQueue handles all synchronization internally. If two threads call TryDequeue(T) at precisely the same moment, neither operation is blocked.

As far as I understand it returns false only if the queue is empty:

If the queue was populated with code such as q.Enqueue("a"); q.Enqueue("b"); q.Enqueue("c"); and two threads concurrently try to dequeue an element, one thread will dequeue a and the other thread will dequeue b. Both calls to TryDequeue(T) will return true, because they were both able to dequeue an element. If each thread goes back to dequeue an additional element, one of the threads will dequeue c and return true, whereas the other thread will find the queue empty and will return false.

http://msdn.microsoft.com/en-us/library/dd287208%28v=vs.100%29.aspx

UPDATE

Perhaps, the easiest option would be using TaskScheduler Class. With it you can wrap all your processing tasks into the queue's items and simplify the implementation of synchronisation.