/**
* Returns an immutable sorted set containing the given elements sorted by the given {@code
* Comparator}. When multiple elements are equivalent according to {@code compare()}, only the
* first one specified is included. This method iterates over {@code elements} at most once.
*
* <p>Despite the method name, this method attempts to avoid actually copying the data when it is
* safe to do so. The exact circumstances under which a copy will or will not be performed are
* undocumented and subject to change.
*
* @throws NullPointerException if {@code comparator} or any of {@code elements} is null
*/
public static <E> ImmutableSortedSet<E> copyOf(
Comparator<? super E> comparator, Iterable<? extends E> elements) {
checkNotNull(comparator);
boolean hasSameComparator = SortedIterables.hasSameComparator(comparator, elements);
if (hasSameComparator && (elements instanceof ImmutableSortedSet)) {
@SuppressWarnings("unchecked")
ImmutableSortedSet<E> original = (ImmutableSortedSet<E>) elements;
if (!original.isPartialView()) {
return original;
}
}
@SuppressWarnings("unchecked") // elements only contains E's; it's safe.
E[] array = (E[]) Iterables.toArray(elements);
return construct(comparator, array.length, array);
}
