Hi David, On Wed, Jul 15, 2009 at 4:36 PM, David Peterson <da...@randombits.org>wrote:
> > Thinking further, I think it's better to separate the EventBus from > the Command system somewhat. The reason being that generally, events > are used to update on changes that have already happened, or are about > to happen. They don't trigger the actual event itself. > My understanding is that some Events need to be fired from the RPC Service (see slide #46 from Ray talk). In my example I have events like EmployeeAddEvent fired only when the RPC call is returned sucessfull, then all views listening this event are notified. > For example, you have a 'CreateUserEvent'. This is sent out and three > listeners pick it up. There is no way to control the order the > handlers are sent the event, so one might actually create the user, > and the others expect it to already be created. You'll have issues at > that point. Also, what happens if the creation fails? Should the event > keep propogating, or stop? I didn't understand your point. I have four listeners and each listener is receiving a diferent Event, then one listener receive employee aditions, other listener employee deletes, etc. (lines 114 to 166) It's also more difficult to provide feedback to the original creator > if there were problems. Yes, it could send out another event over the > bus, but then you end up with custom 'error' events all over the > place... > If an error ocurr with the RPC request then the application wide failure handling (see slide #24) will notify the user about the error. There is no need for new events. > > Anyway, I've ended up implementing them separately. In fact, they are > completely decoupled from each other - so much so that I've got two > separate projects for them: > > Command Pattern API: > http://code.google.com/p/gwt-dispatch > > Presenter Pattern API: > http://code.google.com/p/gwt-presenter Thanks about your comments, I will check your project and send my feedback. Regards, > > On Jul 15, 2:46 am, "Alejandro D. Garin" <aga...@gmail.com> wrote: > > I forget to post the link: > > > > http://puntosoft2k.appspot.com/Showcase.html#ContactWidgetEventBus > > > > Thanks. > > > > On Tue, Jul 14, 2009 at 1:43 PM, Alejandro D. Garin <aga...@gmail.com > >wrote: > > > > > 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, > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
