Hi,
I wrote an implementation (first try) based on the Command Pattern and
EventBus described in the Ray Google IO Talk. (what I understand from the
slides).
The working example is trivial but the code uses an event bus (using gwt
HandleManager) and the command pattern for the RPC Service.
Comments are welcome, I would like to know if the implementation is good.
Thanks,
On Mon, Jul 13, 2009 at 10:31 PM, David Peterson <da...@randombits.org>wrote:
>
> There's certainly nothing to stop you, and you could even just add
> your own RPC Event and have a listener trigger the server-side call.
> In fact, in my own implementation of Ray's example (http://
> code.google.com/p/gwt-dispatch), the Action and Response are both
> interfaces, so you could just have the base class be a GwtEvent
> subclass.
>
> The main complication I guess is the server side. I haven't tested to
> see if you can just use a custom EventHandler server-side without
> changes, but I'm guessing it would work fine.
>
> David
>
>
> On Jul 11, 4:41 pm, Kwhit <kwhitting...@gmail.com> wrote:
> > Just throwing up an idea here to see how many bullet holes it comes
> > down with.
> >
> > I'm playing around with the command pattern which is a hot topic at
> > the moment and wondered why it shouldn't be merged with the EventBus?
> > The command pattern proposed by RR has to add a response object - the
> > original doesn't (I don't have a GoF copy to hand), using and event
> > bus would remove the requirement for it.
> >
> > Using the example presented by RR.
> >
> > 1/ User clicks on 'save' to save the edited phone number
> >
> > 2/ Presenter creates an RpcCommandEvent{<save>, <new phone number>}
> > and fires it to the eventBus
> >
> > 3/ RpcPipe, listening for RpcCommandEvent events, ships them off the
> > to the server
> >
> > --- Server side ---
> >
> > 4/ RpcPipeService receives the event and invokes a specialized handler
> >
> > 5/ The handler verifies (for the sake of the example but I would
> > normally do this client side) the new phone number, finds it OK and
> > updates the storage
> >
> > 6/ Handler returns new phone number for contact ID x
> >
> > 7/ RpcPipeService ships (returns) the response on across the pipe
> >
> > --- Back on the client side ---
> >
> > 8/ RpcPipe fires the RPC return value as an event on the bus
> >
> > 9/ Listeners to ContactInfoUpdated events update the phone number
> >
> > I, in my ignorance, find the above a net gain
> >
> > * +ve: One pipe fits all, no need to update the mechanics of the RPC
> > * +ve, -ve: The event designer has to know that the event should be
> > shipped over the pipe
> > * +ve: The statefulness of the RPC mechanism (every request has a
> > response) fades away
> > * +ve: In fact the Pipe itself could disappear with a bus on the
> > server (see below) - end to end unit testing
> >
> > In my event driven fever I would also like to have an event bus on the
> > server so that the handlers could register themselves for events but I
> > not worried too much about that yet.
> >
> > OK fire away!
> >
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Google Web Toolkit" group.
To post to this group, send email to Google-Web-Toolkit@googlegroups.com
To unsubscribe from this group, send email to
google-web-toolkit+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/Google-Web-Toolkit?hl=en
-~----------~----~----~----~------~----~------~--~---
