/// <summary>
/// Creates an ExecutorCompletionService using the supplied
/// executor for base task execution and the supplied queue as its
/// completion queue.
/// </summary>
/// <param name="executor"> the executor to use </param>
/// <param name="completionQueue"> the queue to use as the completion queue
/// normally one dedicated for use by this service. This
/// queue is treated as unbounded -- failed attempted
/// {@code Queue.add} operations for completed tasks cause
/// them not to be retrievable. </param>
/// <exception cref="NullPointerException"> if executor or completionQueue are {@code null} </exception>
public ExecutorCompletionService(Executor executor, BlockingQueue <Future <V> > completionQueue)
{
if (executor == null || completionQueue == null)
{
throw new NullPointerException();
}
this.Executor = executor;
this.Aes = (executor is AbstractExecutorService) ? (AbstractExecutorService)executor : null;
this.CompletionQueue = completionQueue;
}