/**
* Returns an immutable sorted set containing the elements of a sorted set, sorted by the same
* {@code Comparator}. That behavior differs from {@link #copyOf(Iterable)}, which always uses the
* natural ordering of the elements.
*
* <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.
*
* <p>This method is safe to use even when {@code sortedSet} is a synchronized or concurrent
* collection that is currently being modified by another thread.
*
* @throws NullPointerException if {@code sortedSet} or any of its elements is null
*/
public static <E> ImmutableSortedSet<E> copyOfSorted(SortedSet<E> sortedSet) {
Comparator<? super E> comparator = SortedIterables.comparator(sortedSet);
ImmutableList<E> list = ImmutableList.copyOf(sortedSet);
if (list.isEmpty()) {
return emptySet(comparator);
} else {
return new RegularImmutableSortedSet<E>(list, comparator);
}
}
/**
* Combines multiple iterables into a single iterable. The returned iterable has an iterator that
* traverses the elements of each iterable in {@code inputs}. The input iterators are not polled
* until necessary.
*
* <p>The returned iterable's iterator supports {@code remove()} when the corresponding input
* iterator supports it.
*
* @throws NullPointerException if any of the provided iterables is null
*/
public static <T> Iterable<T> concat(Iterable<? extends T>... inputs) {
return concat(ImmutableList.copyOf(inputs));
}