public static <E> E getOnlyElement(Iterator<E> traversal, E defaultElement) {
if (!traversal.hasNext()) return defaultElement;
E result = traversal.next();
if (traversal.hasNext())
throw new IllegalArgumentException(
"Traversal contains more than 1 element: " + result + ", " + traversal.next());
return result;
}
public static void verifyElementOrder(
Iterator<? extends Element> elements, String key, Order order, int expectedCount) {
Comparable previous = null;
int count = 0;
while (elements.hasNext()) {
Element element = elements.next();
Comparable current = element.value(key);
if (previous != null) {
int cmp = previous.compareTo(current);
assertTrue(
previous + " <> " + current + " @ " + count, order == Order.ASC ? cmp <= 0 : cmp >= 0);
}
previous = current;
count++;
}
assertEquals(expectedCount, count);
}
public static <E> E getOnlyElement(Iterator<E> traversal) {
if (!traversal.hasNext()) throw new NoSuchElementException();
return getOnlyElement(traversal, null);
}