Hmmm, I see my comments about GIN in the ActivityMapper have caught up
with me. I haven't worked this out fully yet, but was thinking of
something along the lines of gwt-presenter's <a
href="http://code.google.com/p/gwt-presenter/source/browse/src/main/java/net/customware/gwt/presenter/client/place/PresenterPlace.java";>PresenterPlace</a>.
My thought is to use GIN in place of the ClientFactory, and to write
ActivityMapper.getActivity() like this:
public Activity getActivity(Place place) {
if (place instanceof ActivityPlace)
{
return ((ActivityPlace) place).getActivity();
}
}
where an ActivityPlace would be obtained from a GIN-aware
PlaceHistoryMapperWithFactory implementation so it can be injected
with the EventBus, etc.
On Wed, Oct 20, 2010 at 8:54 AM, Aigeec <[email protected]> wrote:
> Hey Guys,
>
> I am also interested in an implementation of GWT 2.1 MVP using GIN.
>
> I have made some head way with it.
>
> This has been done mostly by extending the ActivityManager,
> PlaceController and PlaceHistoryHandler classes and overriding their
> constructors to use GIN injection. I don't know if this is the correct
> implementation and if anyone has comments please let me know. But I
> have been able to remove the need for the ClientFactory and use GIN
> injection to instantiate everything but the Activity classes.
>
> However, I do not know how to tackle the ActivityMapper class.
>
> As Tolga says how do we replace the nested if statement with a GIN
> module?
>
> I would much prefer to be able to instantiate the Activity Class this
> way as I am using the SecureDispatchAsync as would like to use DI to
> pass it to the Activity.
>
> Regards,
>
> Aigeec
>
> On Oct 20, 1:31 am, Tolga Tarhan <[email protected]> wrote:
>> Folks,
>>
>> I'm trying to make GWT 2.1 MVP work nicely with GIN. It looks like this use
>> case was specifically considered when
>> creating PlaceHistoryMapperWithFactory, but no such thing seems to exist for
>> ActivityMapper. There is a passing reference to using Gin in
>> DevGuideMvpActivitiesAndPlaces.html , where it says "... ClientFactory is
>> used by HelloActivity to obtain a reference to the HelloView as well as the
>> EventBus and PlaceController. Any of these could alternatively be injected
>> via GIN." and also when it says "A better way to implement the chain of
>> nested ifs would be with a GIN module", in reference to ActivityMapper.
>>
>> The problem, however, is that we cannot both inject application-level
>> objects (EventBus, PlaceController, etc) and also pass the Place as
>> constructor arguments to the Activity. We could have all of the dependencies
>> for every Activity (like all the views) injected into our ActivityMapper and
>> pass them thru, but this leaks a lot of details into what should be a very
>> simple mapper class. If done incorrectly, it would also cause code-splitting
>> issues.
>>
>> One way around this is to inject a Provider<MyActivity> or
>> AsyncProvider<MyActivity> in the ActivityMapper and then do something like
>> myActivityProvider.get().initPlace(place) - which is like the assisted
>> injection that's discussed in the Guice docs. I'm wondering if there's a
>> more elegant way that was considered?
>>
>> Additionally, I'm not sure I understand how to "implement the chain of
>> nested ifs" in a GIN module. This sounds like a great idea, but what did you
>> have in mind to make GIN do this for us? We can have GIN differentiate on a
>> bunch of things (annotations, generics, interfaces, etc), but I don't know
>> how you could replace the if-block with GIN. Could someone point me in the
>> right direction here?
>>
>> Thanks,
>> Tolga
>
> --
> http://groups.google.com/group/Google-Web-Toolkit-Contributors
>
--
David Chandler
Developer Programs Engineer, Google Web Toolkit
http://googlewebtoolkit.blogspot.com/
--
http://groups.google.com/group/Google-Web-Toolkit-Contributors
