I just noticed one caveat with using the Multibinder. I'm doing this:
Multibinder<ConfigContributor> configBinder = Multibinder.newSetBinder
(binder(), ConfigContributor.class);
configBinder.addBinding().to(GlobalConfigContributor.class);
Now in DefaultConfigProcessor.setGlobalContributors, I'm getting the
GlobalConfigContributor class I've bound here as well as all of the values
of the MapBinder for String->ConfigContributor that is bound in the
DefaultConfigContributorModule. I have to add an Annotation when I do
Multibinder.newSetBinder to keep that from happening. This doesn't happen
when I remove my Multibinder and only have the MapBinder... odd. It's
like the MapBinder values are getting added to the Multibinder config
automatically.
Maybe that's why the original code is a List instead of a Set that uses
Multibinder.
-Stanton
From: "Ciancetta, Jesse E." <jc...@mitre.org>
To: "dev@shindig.apache.org" <dev@shindig.apache.org>,
Date: 10/31/2011 12:30
Subject: RE: Injecting global config contributors for the default
config process
>-----Original Message-----
>From: Stanton Sievers [mailto:ssiev...@us.ibm.com]
>Sent: Monday, October 31, 2011 8:12 AM
>To: dev@shindig.apache.org
>Subject: Injecting global config contributors for the default config
process
>
>Hi everyone,
>
>I've recently been looking at the ConfigContributor and ConfigProcessor
>code and the workflow for getting configuration code the JavaScript side
>of things. In DefaultConfigProcessor there is a setGlobalContributors
>method that is injectable and takes a List<ConfigContributor> as a
>parameter. How is this injectable via Guice? I thought it could be done
>with Multibinder but that only seems to allow Set contributions. What is
>the intended way to contribute a List<ConfigContributor> (or any List for
>that matter) with Guice?
It looks like you can use a TypeLiteral to do this:
http://code.google.com/p/google-guice/wiki/FrequentlyAskedQuestions
And if you search the Shindig codebase for usages of TypeLiteral you'll
find a few examples of where it is indeed being used to setup List's for
Guice injection.
However this doesn't seem as flexible as using a Multibinder with a Set
though since with Multibinder it seems you can append to the Set across
any number of different Guice modules, and with the TypeLiteral approach I
don't think that's possible.
I'm far from a Guice expert though so if someone has a better solution
please chime in.
>I found this issue, however, the solution seems to be Multibinder. :)
>http://code.google.com/p/google-guice/issues/detail?id=37&can=2&q=
>
>If there's no good way to do this, I propose changing
>setGlobalContributors to take a Set<ConfigContributor> so that
Multibinder
>can be used. I don't think order or duplicate entries really matter for
>this use case, so I don't see why a Set wouldn't work....
Even though there does seem to be a workaround available I don't see any
reason why this shouldn't be a Set -- and by making it a Set we can use
Multibinder and gain the additional flexibility that buys us in terms of
being able to add to the bindings across multiple Guice modules.
>Thanks,
>-Stanton
