"I'd like that Guice call me when it tries to inject, and so I will return the "better" instance. "
Isn´t this the provider role? You can extend the Provider class too so you can inject other "context" objects into it and decide which instance would be best for the moment. =) Hope this can help you. Best regards, Marcos Alcantara On Tue, Jan 19, 2010 at 11:56 AM, Anthony MULLER <[email protected]>wrote: > Thanks Fred! But my bindings are "modular"... I don't know them before > startup... > > In the example, imagine the injectee must be the instance with the time the > closest of injection time. Or, if no "@Timed" is provided, the default > implementation must be injected. > > // Example > public class MaClasse { > @Inject // Default injection > private ISomething something; > > @Inject @Timed // Timed injection > private ISomething something; > } > > Bindings : > ISomething --> DefaultSomethingImpl // Default > > "Contributors" can provided bindings like: > ISomething @Named("8:15") --> SomethingMorningImpl // Optional > ISomething @Named("12:30") --> SomethingMiddayImpl // Optional > ISomething @Named("20:55") --> SomethingEveningImpl // Optional > > As you see, I don't know the list in advance... > > The provider could be a solution, but the problem is I don't have > information on the injectee (in my case: the attached annotations)... So, I > can not control the injection as I wish :-/ > > Maybe it is possible to do what I wish by using Guice 2.0 and its SPI? > > Regards, > Anthony > > > 2010/1/19 Fred Faber <[email protected]> > >> Anton's suggestion should do the trick: >> >> class ISomethingProvider implements Provider<ISomething> { >> >> @Inject @ReportsTimeOfDay >> TimeOfDayReporter timeOfDayReporter; >> >> @Inject @Name("morning") >> Provider<ISomething> somethingMorningProvider; >> >> @Inject @Name("midday") >> Provider<ISomething> somethingMiddayProvider; >> >> @Inject @Name("evening") >> Provider<ISomething> somethingEveningProvider; >> >> @Override >> public ISomething get() { >> TimeOfDay timeOfDay = timeOfDayReporter.getTimeOfDay(); >> if (timeOfDay.isMorning()) { >> return somethingMorningProvider.get(); >> } else if (....) { >> .... >> } >> } >> } >> >> >> and then: >> >> bind(ISomething.class) >> .toProvider(ISomethingProvider.class); >> >> >> * * * >> >> "injection context" is a vague and simultaneous powerful concept, which is >> different from application to application, and even injection to injection. >> the provider construct allows flexible definitions of this context to suit >> each setting. >> >> -Fred >> >> On Tue, Jan 19, 2010 at 9:18 AM, Anthony MULLER <[email protected] >> > wrote: >> >>> Ok! >>> >>> Imagine I have several bindings for ISomething : >>> >>> ISomething @Named("morning") --> SomethingMorningImpl >>> ISomething @Named("midday") --> SomethingMiddayImpl >>> ISomething @Named("evening") --> SomethingEveningImpl >>> >>> At runtime, I know what time is it and I wish that the proper instance is >>> injected according the time: >>> >>> public class MaClasse { >>> @Inject >>> @Timed >>> private ISomething something; >>> } >>> >>> I'd like that Guice call me when it tries to inject, and so I will return >>> the "better" instance. >>> >>> As you see, the framework is not able to decide alone in that case. But >>> if it is possible to plug behaviour at injection time, this case can be >>> resolved. >>> >>> Hoper I'm clearer :-p >>> >>> Regards, >>> Anthony >>> >>> >>> 2010/1/19 Fred <[email protected]> >>> >>>> Could you please give an example? I'm having a hard time interpreting >>>> >>>> what you mean. >>>> >>>> On Jan 19, 8:15 am, Anthony MULLER <[email protected]> wrote: >>>> > Hello, >>>> > >>>> > I can't remember... I work with Guice 1.0. >>>> > >>>> > Is is possible to take the hand when it is written: >>>> > >>>> > public class MaClasse { >>>> > >>>> > @Inject >>>> > private ISomething something; >>>> > >>>> > } >>>> > >>>> > I'd like to write a specific resolution, to choose the "best" >>>> binding.... >>>> > >>>> > Thanks, >>>> > Anthony >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "google-guice" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]<google-guice%[email protected]> >>>> . >>>> For more options, visit this group at >>>> http://groups.google.com/group/google-guice?hl=en. >>>> >>>> >>>> >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "google-guice" group. >>> To post to this group, send email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]<google-guice%[email protected]> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/google-guice?hl=en. >>> >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "google-guice" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<google-guice%[email protected]> >> . >> For more options, visit this group at >> http://groups.google.com/group/google-guice?hl=en. >> >> > > -- > You received this message because you are subscribed to the Google Groups > "google-guice" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-guice%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-guice?hl=en. > >--
You received this message because you are subscribed to the Google Groups "google-guice" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to [email protected].
For more options, visit this group at http://groups.google.com/group/google-guice?hl=en.
