Multibinds

Annotates abstract module methods that declare multibindings.

You can declare that a multibound set or map is bound by annotating an abstract module method that returns the set or map you want to declare with @Multibinds.

You do not have to use @Multibinds for sets or maps that have at least one contribution, but you do have to declare them if they may be empty.

@DependencyGraph interface MyGraph {
  @Multibinds aSet(): Set<Foo>
  @Multibinds @MyQualifier aQualifiedSet(): Set<Foo>
  @Multibinds aMap(): Map<String, Foo>
  @Multibinds @MyQualifier aQualifiedMap(): Map<String, Foo>

  @Provides
  fun usesMultibindings(set: Set<Foo>, @MyQualifier map: Map<String, Foo>): Any {
    return …
  }
}

A given set or map multibinding can be declared any number of times without error. Dagger never implements or calls any @Multibinds methods.