GIN injection of field in abstract class

Question

I'm working in some GWT application in which I have a hierarchy where I have an abstract presenter with some common functionality of derived classes. Something like:

public abstract class MyAbstractPresenter<T extends MyAbstractPresenter.CustomDisplay> extends Presenter<T>
{
public interface CustomDisplay extends View
{
  //some methods
}

//I want to inject this element
@Inject
private CustomObject myObj;

public MyAbstractPresenter(T display)
{
   super(display);
}
}

All the subclasses get injected properly. However, I want to be able to inject that particular field without having it to add it in the constructor of the subclasses. I tried to do field injection as you see , but it doesn't work as it is the subclasses the one that get injected.

Is there a proper way to achieve this Injection without letting the subclasses know about the existence of the field?

Is Guice can be used in GWT on the client side? As I know exist Gin implementation - Guice for GWT client side. — Taky, Jan 28 '13 at 13:37
Its build on top of guice anyway and since my question applies to other cases, I thought of leaving it more general. — Sednus, Jan 28 '13 at 13:40

score 1 · Accepted Answer · answered Jan 28 '13 at 18:30

Apparently, as for the moment, there is no support for this type of behavior in GIN. A workaround would be to inject the required field in the concrete classes constructors even when they don't need it. Something like:

 public abstract class MyAbstractPresenter<T extends MyAbstractPresenter.CustomDisplay> extends Presenter<T>
 {
   public interface CustomDisplay extends View
   {
     //some methods
   }

   //I wanted to inject this element
   private final CustomObject myObj;

   public MyAbstractPresenter(T display, CustomObject obj)
   {
      super(display);
      myObj = obj;
   }
}

Then in any class that extends this abstract implementation, I would have to pass it on construction.

public abstract class MyConcretePresenter extends MyAbstractPresenter<MyConcretePresenter.CustomDisplay>
{
  public interface CustomDisplay extends MyAbstractPresenter.CustomDisplay
  {
     //some methods
  }

 @Inject  //it would get injected here instead.
 public MyConcretePresenter(CustomDisplay display, CustomObject obj)
 {
     super(display, obj);
 }
}

GIN injection of field in abstract class

1 Answers1