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

[Stuart McCulloch <mcculls@xxxxxxxxx>]

On 1 Feb 2014, at 18:04, Benson Margulies <benson@xxxxxxxxxxxxx> wrote:

> 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?

https://github.com/eclipse/sisu hosts the source for the main site (PHP driven) plus the tutorials at http://eclipse.org/sisu/docs/tutorials/index.html - pull requests welcome.

MediaWiki content can be added under http://wiki.eclipse.org/Sisu - if you don’t have a login you can get one from https://dev.eclipse.org/site_login/createaccount.php

See also http://wiki.eclipse.org/Main_Page for general editing help.

Otherwise, feel free to send content via the mailing list and I can add it to either the wiki or as a new tutorial / FAQ.

> 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.