Menu
I need to bind one class as implementation of two interfaces. And it should be binded in a singleton scope.
What I've done:
bind(FirstSettings.class). to(DefaultSettings.class). in(Singleton.class); bind(SecondSettings.class). to(DefaultSettings.class). in(Singleton.class); But, obviously, it leads to creation of two different instances, because they are binded to the different keys.
My question is how can I do that?
207
However, it can be achieved with interfaces, because the class can implement multiple interfaces. Note: To implement multiple interfaces, separate them with a comma (see example below).
Note that the only Guice-specific code in the above is the @Inject annotation. This annotation marks an injection point. Guice will attempt to reconcile the dependencies implied by the annotated constructor, method, or field.
Guice figures out how to give you an Emailer based on the type. If it's a simple object, it'll instantiate it and pass it in. If it has dependencies, it will resolve those dependencies, pass them into it's constructor, then pass the resulting object into your object.
Overview of bindings in Guice. A binding is an object that corresponds to an entry in the Guice map. You add new entries into the Guice map by creating bindings.
Guice's wiki has a documentation about this use case.
Basically, this is what you should do:
// Declare that the provider of DefaultSettings is a singleton bind(DefaultSettings.class).in(Singleton.class); // Bind the providers of the interfaces FirstSettings and SecondSettings // to the provider of DefaultSettings (which is a singleton as defined above) bind(FirstSettings.class).to(DefaultSettings.class); bind(SecondSettings.class).to(DefaultSettings.class); There is no need to specify any additional classes: just think in terms of Providers and the answer comes rather naturally.
51
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
