dagger.android without O(N) subcomponents

MonolithicActivityInjector.java

@Subcomponent
public abstract class MonolithicActivityInjector implements AndroidInjector<Activity> {
  @Override
  public final void inject(Activity activity) {
    if (activity instanceof RedActivity) {
      inject((RedActivity) activity);
    } else if (activity instanceof BlueActivity) {
      inject((BlueActivity) activity);
    } else if (activity instanceof YellowActivity) {
      inject((YellowActivity) activity);
    } else {
      throw new IllegalArgumentException();
    }
    
    /* btw, you should totally codegen this:
    @MonolithicActivitySubcomponent({
      RedActivity.class,
      BlueActivity.class,
      YellowActivity.class,
    })
    interface Foo {}
    */
    
    // or, if you want something that's not linear, but not proguardable:
    
    switch (activity.getClass().getName()) {
      case "com.example.RedActivity": inject((RedActivity) activity); break;
      case "com.example.BlueActivity": inject((BlueActivity) activity); break;
      case "com.example.YellowActivity": inject((YellowActivity) activity); break;    
      default: throw new IllegalArgumentException();
    }
    
    // or some other clever technique
  }
  
  public abstract void inject(RedActivity red);
  public abstract void inject(BlueActivity blue);
  public abstract void inject(YellowActivity yellow);
}