On 20 Jul 2013, at 13:04, Graham Ashton <gra...@effectif.com> wrote:
> What responsibilities does a KitchenHandler have? There's no such thing in > real life; could its existence be a side effect of the implementation? I could call it Chef, or Cook, or KitchenAssistant or something. Everything in the system is the result of being instructed to perform a command, and the generic term for these is "handler", hence I used it above. I'm currently refactoring from an Application Service pattern with methods that accept hashes, to command messages being sent over a bus, because it gives me some useful stuff for free. I haven't got far along this route yet, so I don't know what good metaphors (if any) I'll find for the handlers yet. > Could you keep the bus, but rework things so that you deal with a Kitchen > object instead? Could you send it a message via your bus just by calling > kitchen.turn_on_kettle ? Actually, yes I could do this, although I think not in the way you're describing. I could keep the Application Service methods, and re-implement them to send command messages. Alternatively, I could implement all the command handlers to call existing service methods. I suspect I'll want one or other of these, so I've got a less verbose API for use in Rake tasks, in a console etc. But I don't know what it will look like yet. > I realise that you're dealing with a message bus, which implies that there > might be all sorts of bits of gumph inbetween your user of the message bus > and the kettle, but might you be able to re-jig your objects this way anyway? Actually it's really simple, but I want to keep a clean separation. One of my HTTP resource POST tests is basically "assert <this command> was put on the bus". Using command messages means I can leverage a basic message typing system I built for events, so it's impossible to put a malformed command on the bus, which also makes it trivial to correctly return 400 Bad Request over HTTP. > Just throwing it out there... I appreciate it might not be an actionable or > useful thought. > > I'm still only a fifth of the way through his book, but I suspect it might be > what David West might ask. > > http://www.amazon.co.uk/Object-Thinking-DV-Microsoft-Professional-David/dp/0735619654/ref=pd_sim_b_3 I just went to add this to Goodreads and found it already there :-) I've bumped it up my list though. > Another unrelated thought; could you use "publish" instead of "send"? Yes, in a way I mentioned in a different email. But it'd need me to make my message typing more sophisticated. I think this is the way I will go eventually, in which case I might decide to just use "publish". I'm not sure yet. Thanks for your thoughts Ash -- http://www.patchspace.co.uk/ http://www.linkedin.com/in/ashmoran -- You received this message because you are subscribed to the Google Groups "NWRUG" group. To unsubscribe from this group and stop receiving emails from it, send an email to nwrug-members+unsubscr...@googlegroups.com. To post to this group, send email to nwrug-members@googlegroups.com. Visit this group at http://groups.google.com/group/nwrug-members. For more options, visit https://groups.google.com/groups/opt_out.
