Question

A Collection is an Iterable with a size, for which you’re allowed to check containment, and add or remove elements. I have objects which inherit Iterable and have a size, but not the other features of a Collection. I don’t want to implement the Collection method with ‘Unsupported’ exceptions.

Is there some commonly-used middle-of-the-way class between Iterable and Collection which I can have my objects extend? Something like ‘SizedIterable’? Or, more generally, an appropriate idiom?

Note: Yes, it really can’t check membership but has a size.

Answer 1

Why don’t you create your own Interface extending Iterable? That way you can define which features you’ll add to your custom object.

Something like this perhaps

public interface SizedIterable<T> extends Iterable<T> {
    int size();
}