Java inheritance and generic issue

Question

I'm having the following classes/interfaces:

public class GenericViewModel<T extends AbstractDatabaseObject> {
    private Class<?> type;

    @SuppressWarnings("unchecked")
    public GenericViewModel(Class<?> cl) {

       type = cl;   
    }      
}

and a specialization:

public class PersonViewModel extends GenericViewModel<Person> implements IPersonViewModel{  
    public PersonViewModel() {
        super(Person.class);
    }

}

Now, my problem is in the presenter:

public class GenericPresenter implements IGenericView.IGenericViewListener {

    private GenericViewModel<AbstractDatabaseObject> model;
    private IGenericView view;

    public GenericPresenter(GenericViewModel<AbstractDatabaseObject> model, IGenericView view) {
        this.model = model;
        this.view = view;
        view.addListener(this);
    }
}

To be more precise, I cannot call the constructor of the super class with the given arguments:

public class PersonPresenter extends GenericPresenter {

    PersonViewModel model;
    IPersonView view;

    public PersonPresenter(PersonViewModel model, IPersonView view) {

        super(model, view); // Here is the problem. No such constructor in superclass found


    // IGenericView i = (IGenericView) view;  <-- this seems to work
    // GenericViewModel<AbstractDatabaseObject> m = model; <-- this doesn't


     }
}

What do I have to change?

Have you tried private GenericViewModel<? extends AbstractDatabaseObject> model;? — tobias_k
– tobias_k, Commented May 27, 2015 at 12:08
Have you tried to cast directly into the super : super( (GenericViewModel<AbstractDatabaseObject>) model, (IGenericView) view); — romfret
– romfret, Commented May 27, 2015 at 12:12

Tagir Valeev · Accepted Answer · 2015-05-27 12:14:25Z

1

Try to change the GenericPresenter class in this way:

private GenericViewModel<? extends AbstractDatabaseObject> model;
private IGenericView view;

public GenericPresenter(GenericViewModel<? extends AbstractDatabaseObject> model, 
                        IGenericView view) {
    this.model = model;
    this.view = view;
    view.addListener(this);
}

answered May 27, 2015 at 12:14

Tagir Valeev

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