public interface <T> {

	boolean hasNext();

	T next();
}


public class ConcreteIterator<Item> implements <Item> {

	private Item[] items;
	private int position = 0;

	public ConcreteIterator(Item[] items) {
		this.items = items;
	}

	
	public boolean hasNext() {
		return position < items.length;
	}

	
	public Item next() {
		return items[position++];
	}
}

public class IteratorTest {

	public static void main(String[] args) {
		Integer[] items = new Integer[10];
		for (int i = 0; i < items.length; i++) {
			items[i] = i;
		}
		Iterator<Integer> iterator = new ConcreteIterator<>(items);
		while (iterator.hasNext()) {
			System.out.println(iterator.next());
		}
	}
}