Package dagger

Annotation Interface Component.Builder

Enclosing class:

Component

@Retention(RUNTIME)
@Target(TYPE)
@Documented
public static @interface Component.Builder

A builder for a component.

A builder is a type with setter methods for the modules, dependencies and bound instances required by the component and a single no-argument build method that creates a new component instance.

Components may have a single nested static abstract class or interface annotated with @Component.Builder. If they do, then Dagger will generate a builder class that implements that type. Note that a component with a @Component.Builder may not also have a @Component.Factory.

Builder types must follow some rules:

• There must be exactly one abstract no-argument method that returns the component type or one of its supertypes, called the "build method".
• There may be other other abstract methods, called "setter methods".
• Setter methods must take a single argument and return void, the builder type or a supertype of the builder type.
• There must be a setter method for each component dependency.
• There must be a setter method for each non-abstract module that has non-static binding methods, unless Dagger can instantiate that module with a visible no-argument constructor.
• There may be setter methods for modules that Dagger can instantiate or does not need to instantiate.
• There may be setter methods annotated with @BindsInstance. These methods bind the instance passed to them within the component. See @BindsInstance for more information.
• There may be non-abstract methods, but they are ignored as far as validation and builder generation are concerned.

For example, this could be a valid Component with a Builder:

 @Component(modules = {BackendModule.class, FrontendModule.class})
 interface MyComponent {
   MyWidget myWidget();

   @Component.Builder
   interface Builder {
     Builder backendModule(BackendModule bm);
     Builder frontendModule(FrontendModule fm);
     @BindsInstance
     Builder foo(Foo foo);
     MyComponent build();
   }
 }