dependency injection - How do I use inject a field using a Dagger 2 multi-binding? -

i'm trying support third party extensions using map multibindings, can't wrap head around how it's supposed provide extensible infrastructure. seems should simple, dagger 2 documentation on multibindings doesn't provide example of how it. want other developers able write own implementations of interface provide, , have seamlessly integrate.

here's sample code shows i'm attempting do:

// interface third parties can implement. public interface fooservice {   public void run(); }  // default implementation of interface provide. class defaultfooimpl implements fooservice {   defaultfooimpl() { ... }   @override public void run() { ... } }  // third parties need add own modules provide // implementations of fooservice on different keys (right?). @module class defaultimplmodule {   @provides(type = map)   @stringkey("default")   static fooservice providedefaultimpl() {     return new defaultfooimpl();   } }  // problem! won't work third-party implementations, since // can't include modules here because don't know them. @component(modules = defaultimplmodule.class) interface fooservicecomponents {   map<string, fooservice> fooservices(); }  public class foodispatcher {   // problem! how inject map?  work?   @inject map<string, fooservice> fooservices;    void callfooservice(string whichservice) {     // whichservice of strings in combined services map.     // default implementation, you'd pass in "default".     this.fooservices.get(whichservice).run();   } } 

so what's missing piece ties , makes work? thanks.

here pattern use - module have configured @ time of using component builder passing arguments. strongly recommend sparing usage , if needed - things should simple need them be, not more :-)

@module class configurablemodule {      private idependencyone one;     private idependencytwo two;     ...      configurablemodule() {      }      configurablemodule(idependencyone one, idependencytwo two, ...) {         this.one = one;         this.two = two;     }       @provides idependencyone getidependencyone(myidependencyoneimpl impl) {         return 1 == null ? impl : one;     }      @provides idependencytwo getidependencytwo(myidependencytwoimpl impl) {         return 1 == null ? impl : one;     } }