Resolving dependency marked with @Named ?

[aryaxt]

I have a class called SomePresenter.
I provide two instances of this class one @nAmed("1") and other @nAmed("2")
In the code I need to resolve this dependency depending on some data and logic, therefore I can't do property injection or constructor injection.

private String type;

public void someMethod() {
   // get an instance of SomePresenter ("1" or "2") depending on the value of "type"
   SomePresenter presenter = objectGraph.get(SomePresenter.class);
}

[jskierbi]

As stated in javadocs, this method throws:

IllegalArgumentException if type is not one of this object graph's injectable types.

As I understand, your SomePresenter is not an injectible type, instead being provided in two named flavours in a module. Correct me if I'm wrong - but it seems that dagger won't let You do that.

[aryaxt]

Thanks for the quick response. Yes, SomePresenter is being provided by my module.
I guess I have to find another way around this.

[tbroyer]

You basically have two options (which are not dagger-specific):

• if the type with someMethod is managed by Dagger, then inject providers of those 2 flavors and choose the one to get() from depending on the value of type

@Inject @Named("1") Provider<SomePresenter> presenter1Provider;
@Inject @Named("2") Provider<SomePresenter> presenter2Provider;

public void someMethod() {
   SomePresenter presenter = /* use presenter1Provider or presenter2Provider */.get();
}

• otherwise, create the ObjectGraph with different modules depending on the value of type; those modules will provide SomePresenter without qualifier so you can use objectGraph.get(SomePresenter.class)

[cgruber]

I would suggest a slight alteration of Thomas' option-1 code to:

class PresenterEntryPoint {
   @Inject @Named("1") Lazy<SomePresenter> presenter1;
   @Inject @Named("2") Lazy<SomePresenter> presenter2;
}

... but it's basically the same approach. Dagger 1.0 is definitely
designed around having robust entry-point/injectable objects, rather
than using ObjectGraph like a big annotated map.

[aryaxt]

Thanks for the great answers. I took the provider approach.