How can I construct a class when the super class uses @Inject?

Question

I have the following code:

public abstract class AbstractClass<T> {

 final A a;

 @Inject
 AbstractClass(A a) {
   this.a = a;
 }
}

public class B extends AbstractClass<C> {

  final D d;

   @Inject
   B(D d) {
     super(); // this fails
     this.d = d;
   }

}

My class B extends AbstractClass and AbstractClass uses @Inject to inject A into it. In class B I cannot call super() because AbstractClass has an argument in the constructor. How can I handle the dependency injection of the superclass in the subclass to get super() working?

How can I construct a class when the superclass uses @Inject?

Sorry A was AbstractClass corrected. – Michael Jan 06 '15 at 21:23 — Michael, Jan 06 '15 at 21:23

score 4 · Accepted Answer · edited Jan 11 '15 at 20:45

You need to accept an A as well:

@Inject
B(A a, D d) {
  super(a);
  this.d = d;
}

Then Guice should inject both the A and the D, and you just pass the A up to the superclass constructor. Just because a constructor is marked with @Inject doesn't mean it can only be invoked by Guice... In fact, I would actually remove the @Inject from AbstractClass - unless Guice has some magic I'm unaware of, it's not going to be able to inject that anyway.

How can I construct a class when the super class uses @Inject?

1 Answers1