Expert to Expert: Erik Meijer and Bertrand Meyer - Objects, Contracts, Concurrency, Sleeping Barbers

Here is a CCR implementation of the Sleeping Barber(s).
Optionally, we can add barbers (threads).
As shown, this is actually a pretty clean pattern using Ports and lamdas and hides the locks and such in the runtime. User level locks on shared state could still be needed in the lambda.  So it is not something that has to be "baked" into a language itself as this works pretty clean as a library.

I really like a few of ideas in this video in general:
1) I like the ccr Port abstraction. For some reason I like endpoints and messages.
2) I like the idea of Pre and Post conditions. This could be added to c#. Think spec# has.
3) I like the idea explicit handling of Query and Command on shared state.  It allows tooling and static and runtime checks.
4) I like the idea un-named types like Tuples. c# has anonymous types, but you can't pass them around.
5) I love the idea of Transactions for object state and have them work with normal DB transactions for rollback.  That seems to be a winning pattern for handling shared state and something like CCR below for handling concurrency and coordination.

private void button20_Click(object sender, EventArgs e)
{
    // Have 1 Barber and N chairs. You can add Barbers (i.e. Threads in the pool) by changing the Dispatcher ctor.
    Port<string> chairsPort = new Port<string>();
    DispatcherQueue dq = new DispatcherQueue("Barber", new Dispatcher(1, "BarberPool"));
    Arbiter.Activate(dq, Arbiter.Receive(true, chairsPort, (string name) =>
        {
            Thread.Sleep(100); // Time to cut hair.
            Console.WriteLine("Customer {0} thanks the barber for the cut on thread {1}.", name, Thread.CurrentThread.ManagedThreadId);
        }));
    for (int i = 0; i < 15; i++)
        chairsPort.Post("Customer" + i);
}