Implement Java Iterator and Iterable in same class?

Question

I am trying to understand Java Iterator and Iterable interfaces

I am writing this class

class MyClass implements Iterable&         


        

Answer 1

I suppose this is a standard way to implement the Iterable and Iterator at the same time.

// return list of neighbors of v
public Iterable adj(int v) {
    return new AdjIterator(v);
}

// support iteration over graph vertices
private class AdjIterator implements Iterator, Iterable {
    private int v;
    private int w = 0;

    AdjIterator(int v) {
        this.v = v;
    }

    public Iterator iterator() {
        return this;
    }

    public boolean hasNext() {
        while (w < V) {
            if (adj[v][w]) return true;
            w++;
        }
        return false;
    }

    public Integer next() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        return w++;
    }

Reference https://algs4.cs.princeton.edu/41graph/AdjMatrixGraph.java.html.