Re: [sisu-users] Having trouble customizing one binding

[Benson Margulies <benson@xxxxxxxxxxxxx>]

I'm sorry to have bothered you with this. I had copied the @Parameter
use from a test case of yours without taking enough time to study it;
@Parameter is completely wrong for my purpose, I should have just left
it at @Provides or written some EDSL in the configure method.

I might now create a wiki from this email thread -- unless you want
pull requests on the doc. Is the web side mirrored on github for that
purpose?


On Sat, Feb 1, 2014 at 12:58 PM, Stuart McCulloch <mcculls@xxxxxxxxx> wrote:
> On 1 Feb 2014, at 13:32, Benson Margulies <benson@xxxxxxxxxxxxx> wrote:
>
>> I want to take detailed control of one binding.
>>
>> In a module, I would write:
>>
>> @Override
>>            protected void configure()
>>            {
>>
>> bind(JsonFactory.class).annotatedWith(WsBusTicketCodecJsonFactory.class).to(SmileFactory.class);
>>            }
>>
>> If I make a module by extending AbstractModule with this code, I have
>> a choice of two failure.
>>
>> If I pass it to the injector ahead of WireModule, Guice complains that
>> I have a duplicate binding for this binding.
>>
>> If I pass it to the WireModule as the first parameter, I stuck on a
>> different problem.
>>
>> My module has several @Parameters-annotated methods. One is:
>>
>> @Provides
>>            @Parameters
>>            WsBusConfig config() {
>>                return new WsBusConfig(configFilePathname);
>>            }
>
> Hi Benson,
>
> Just wondering why you use @Parameters here, because the original aim of this annotation was for binding (or injecting) configuration maps - or argument arrays, like the String[] args you get from main:
>
>         @Inject
>         @Parameters
>         Map<?, ?> properties;
>
>         @Inject
>         @Parameters
>         String[] args;
>
> WireModule will merge multiple @Parameters bindings - for maps by merging the contents, for string arrays by concatenating them - so when you @Inject @Parameters Map/String[] you get the merged content:
>
>         https://github.com/eclipse/sisu.inject/blob/master/org.eclipse.sisu.inject/src/org/eclipse/sisu/wire/ElementAnalyzer.java#L286
>
> Because WsBusConfig is not a Map (or a String array), the ElementAnalyzer doesn’t know how to merge it and you get the “ Ignoring incompatible @Parameters binding” error message.
>
> If you just want to @Inject your WsBusConfig (ie. not access it via the injected @Parameters Map) then you don’t need the @Parameters annotation, and removing this annotation will avoid the error.
>
> But if you want to add this object as an element of the injected @Parameters Map instead of @Inject it directly then you could change the binding to:
>
>         @Provides
>         @Parameters
>         Map<?,?> config() {
>                 return Collections.singletonMap(“some.key”, new WsBusConfig(configFilePathname));
>         }
>
> in which case it would then get merged in with the other @Parameters bindings.
>
> PS. if you wanted to override elements, but didn’t want to put the overriding module inside WireModule then you could always use the Modules utility class from Guice:
>
>         Modules.override( new WireModule( appModules ) ).with( overridingModule );
>
>         http://google-guice.googlecode.com/git/javadoc/com/google/inject/util/Modules.html
>
> We could also look at enhancing the ElementAnalyzer code above to treat non-map @Parameters bindings as a single key-value element - if this is what you expected it to do?
>
> HTH
>
> —
> Cheers, Stuart
>
>> When my module is outside of WireModule, all is well. When it's inside, I get
>>
>> WARN: Sisu - Ignoring incompatible @Parameters binding:
>> ProviderInstanceBinding[key=Key[type=com.basistech.wsbus.api.WsBusConfig,
>> annotation=@org.eclipse.sisu.Parameters],
>> source=com.basistech.wsbus.api.WsBusConfig
>> com.basistech.wsbus.launcher.BusBootstrap$1.config(),
>> scope=Scopes.NO_SCOPE, provider=@Provides
>> com.basistech.wsbus.launcher.BusBootstrap$1.config(BusBootstrap.java:91)]
>>
>> followed by a cascade of problem when that value is not in fact injected.
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>
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