Re: MVP with multiple EntryPoints

On Wednesday, September 12, 2012 12:53:58 AM UTC+2, Cristian Rinaldi wrote:

We have an application with multiple EntryPoints. Each EntryPoint contains an MVP configuration with their own PlaceHistoryHandler, PlaceHistoryMapper and PlaceController. Depending on the order that the history handlers were configured, the place treatment is overlapped. I think the problem is raised because the implementation of PlaceHistoryHandler invokes PlaceController.goTo(NOWHERE) when the PlaceHistoryMapper do not find the place, because this place is associated with the PlaceHistoryMapper of another EntryPoint. How I can solve this problem? It is right to use MVP with multiple EntryPoints?

First, Places (and Activities) have nothing to do with MVP.

To answer your question, I'd rather say it's not quite right to load several distinct apps in a page that tweak the URL and react to its changes, independently of the others. The thing is, the URL –as its name says– represents some "location" (hence the name "place" in GWT), and if you have several independent things on a page, there's no nothing like *one* location for the whole thing. You could use a "complex" URL containing the "state" of each subparts (e.g. moduleA=a&moduleB=b&moduleC=c), but that would be suboptimal in terms of user experience (back to the UX of frames, except with a bookmarkable URL).

Let's imagine for a second that you make your apps work by "ignoring" unknown places (that's what you were looking for right? avoiding the goTo(NOWHERE) –or whatever is your default place actually– when PlaceHistoryMapper doesn't understand the history token?).

1. the app loads and displays A1, B1 and C1
2. user navigates in each module:
1. A2, B1, C1 ⇒ URL is #A2
2. A2, B2, C1 ⇒ URL is #B2
3. A2, B2, C2 ⇒ URL is #C2
3. user uses his browser's back button ⇒ URL is #B2; nothing changes on screen, because module B is already at B2, and modules A and C ignore the place

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