iterator

interface Selector {
boolean end();
Object current();
void next();
}


public class Sequence {


private Object[] items;
private int next = 0;

public Sequence(int size) {
items = new Object[size];
}

public void add(Object x) {
if(next < items.length) {
items[next++] = x;
}
}

private class SequenceSelector implements Selector {
private int i;

public boolean end() {
return i == items.length;
}

public Object current() {
return items[i];
}

public void next() {
if (i < items.length) {
i++;
}
}
}

public Selector selector() {
return new SequenceSelector();
}

public static void main(String[] args) {
Sequence sequence = new Sequence(10);
for (int i = 0; i < 10; i++)
sequence.add(Integer.toString(i));
Selector selector = sequence.selector();
while (!selector.end()) {
System.out.println(selector.current());
selector.next();
}
}
}