//--- Constructors ---
/// <summary>
/// Create an instance of the work queue.
/// </summary>
/// <param name="handler">Dispatch action for work item Type and with completion callback.</param>
/// <param name="maxParallelism">Maximum number of items being dispatch simultaneously against the dispatch queue.</param>
/// <param name="dispatchQueue">Dispatch queue for work items.</param>
public ProcessingQueue(Action <T, Action> handler, int maxParallelism, IDispatchQueue dispatchQueue)
{
if (dispatchQueue == null)
{
throw new ArgumentNullException("dispatchQueue");
}
if (handler == null)
{
throw new ArgumentNullException("handler");
}
if ((maxParallelism <= 0) || (maxParallelism > MAX_PARALLELISM))
{
throw new ArgumentException(string.Format("maxParallelism must be between 1 and {0:#,##0}", MAX_PARALLELISM), "maxParallelism");
}
_handler = handler;
_dispatchQueue = dispatchQueue;
// prime the pending queue with dispatchers
for (var i = 0; i < maxParallelism; ++i)
{
if (!_pending.TryEnqueue(StartWorkItem))
{
throw new NotSupportedException();
}
}
}
//--- Methods ---
/// <summary>
/// Try to queue a work item for dispatch.
/// </summary>
/// <param name="item">Item to add to queue.</param>
/// <returns><see langword="True"/> if the enqueue succeeded.</returns>
public bool TryEnqueue(T item)
{
if ((_inbox != null) && (Interlocked.Decrement(ref _capacity) < 0))
{
return(_inbox.TryEnqueue(item));
}
return(TryStartWorkItem(item));
}
