如果我已经有一个泛型的实现，如何声明一个接口方法

Question

I want to make EventsRepository class to implement an Interface. So it has some method:

public class EventsRepository implements IModelLayer {
 ...   
    public void getEvents(ICallback<EventBrite> resultEvents) {
        WebEventsDataSource.getInstance().getEvents(resultEvents);
    }
}

and this method has to implement some interface. On the basis of this method, what kind of interface method's semantic do i have to declare? I tried to declare next interface:

public interface IModelLayer<T> {
    void getEvents(T resultEvents);
}

but it is not correct.

Thanks a lot!

Answer 1

The generic implementation and declaration would look like that:

public interface IModelLayer<T> {
    void getEvents(T resultEvents);
}

The interface is already right defined just the implementation of it needs to be changed.

Class implementation:

public class EventsRepository implements IModelLayer<ICallBack<EventBrite>> { //Generic type definition
...   
    @Override
    public void getEvents(ICallback<EventBrite> resultEvents) {
        WebEventsDataSource.getInstance().getEvents(resultEvents);
    }
}

For example in other cases:

public class StringRepository implements IModelLayer<ICallBack<String>> { //Generic type definition
...   
    @Override
    public void getEvents(ICallback<String> resultEvents) {
        //todo do something with the callback stuff.
    }
}

The thing here is you haven't defined the generic type you want to use. So you change implements IModelLayer to implements ModelLayer<YourType> and the method will use the type you defined.

Answer 2

You are almost there, you forgot the type, try with:

public class EventsRepository implements IModelLayer<ICallback<EventBrite>>{
    @Override
    public void getEvents(ICallback<EventBrite> resultEvents) {
            WebEventsDataSource.getInstance().getEvents(resultEvents);
    }
}

Answer 3

implements like below..this may help

      public class EventsRepository implements IModelLayer<ICallback<EventBrite>> {
        public void getEvents(ICallback<EventBrite> resultEvents) {
           WebEventsDataSource.getInstance().getEvents(resultEvents);
       }
      }

Answer 4

If getEvents parameter is always an ICallback , you can define the interface and class as follows:

public interface IModelLayer<T> {
    void getEvents(ICallback<T> resultEvents);
}

public class EventsRepository implements IModelLayer<EventBrite> {
 ...   
    public void getEvents(ICallback<EventBrite> resultEvents) {
        WebEventsDataSource.getInstance().getEvents(resultEvents);
    }
}

Of course, the definition of WebEventsDataSource.getInstance().getEvents() might also affect the answer.