Concurrency

This will be the last post on rebuilding the MailboxProcessor using TDF, here’s a quick discussion of the missing pieces…

First, lets start with the simple ones, these don’t really require much discussion.

DefaultTimeout

let mutable defaultTimeout = Timeout.Infinite

member x.DefaultTimeout
   with get() = defaultTimeout
   and set(value) = defaultTimeout <- value

This simply provides a mutable property using Timeout.Infinite as a default setting.

CurrentQueueLength

member x.CurrentQueueLength() = incomingMessages.Count 

Another simple one, this methods uses into the underlying BufferBlock to extract its current queue length using its Count property.

Right, no messing about this time, straight to the code.

Construction

This is pretty straight forward and I don’t want to detract from the important bits of this post, the only thing of note is the cancellationToken which is initialized to a default value using the defaultArg function if the optional parameter cancellationToken is not supplied. The TDF construct that we to use to perform most of the hard work is incomingMessages which is a BufferBlock<'Msg>.

This is going to be a new series on using TPL Dataflow with F#. First a little bit of history and background.

TPL Dataflows heritage and background

TPL Dataflow or (TDF) has been around for quite a while, it first surfaced more than a year ago as the successor to the Concurrency and Coordination Runtime (CCR) and with coming release of .Net 4.5 it will be part of the System.Threading.Tasks.Dataflow namespace. Elements of the now halted project Axum are also present within the design of TDF.