how to avoid repetitive constructor in children

Question

I have a parent class, which has constructor as:

    @Inject
    public AbstractResource(@Named("authorization") Authorization auth,
                            @Named("helper") Helper helper) {
        this.authorization = authorization;
        this.helper = helper;
    }

now in the children class, i have similar constructor:

public class MyResource extends AbstractResource {
        private Manager manager;

        @Inject
        public MyResource(@Named("authorization") Authorization auth,
                          @Named("helper") Helper helper) {
            super(auth, helper);
            this.manager = new Manager();
        }
...

Problem is I have tons of children class extend from AbstractResource, I have to write the similar constructor with 'Authorization' and 'Helper' again and agin. is there any way i can avoid the repetitive coding?

Sorry, updated my code, yes, i can call super(..) in each children class, but still in each constructor i have inject all those parameters, auth and helper, just wonder if there is a way to even simplify that

With constructor injection, no. But you could use setter or field injection if you find it fine. — JB Nizet, Feb 12 '16 at 21:48
almost dupe but I think you're interested in the Guice or Spring case http://stackoverflow.com/questions/1644317/java-constructor-inheritance — djechlin, Feb 12 '16 at 21:49

Charles Durham · Answer 1 · 2016-02-12T21:51:26.160

1

Unless I'm missing something about this there is a simple solution by calling through to the parent's constructor.

In your child class's constructor the first line should be: super(authorization, helper)

EDIT: Author has edited his question so this solution is no longer applicable.

edited Feb 12 '16 at 21:51

answered Feb 12 '16 at 21:48

Charles Durham

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This is what I thought too, but I'm not too familiar with the @Named Annotation. – Luka Jacobowitz Feb 12 '16 at 21:49
This looks right. You can get rid of 1/2 the boilerplate, not the other half. – djechlin Feb 12 '16 at 21:51
If your answer is no longer applicable, I suggest you delete it. – aioobe Feb 12 '16 at 21:55

score 1 · Answer 2 · answered Feb 12 '16 at 21:48

1

You can create an object to hold all the arguments.

But other than that, no not really. This is what production DI code in Java actually looks like.

answered Feb 12 '16 at 21:48

djechlin

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how to avoid repetitive constructor in children

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