/**
* Creates a Tree of the given elements.
*
* <p>If the given iterable is a tree, it is returned as result. if the iteration order of the
* elements is stable.
*
* @param <T> Component type of the List.
* @param iterable An Iterable of elements.
* @return A list containing the given elements in the same order.
* @throws NullPointerException if {@code elements} is null
*/
@SuppressWarnings("unchecked")
static <T> Tree<T> ofAll(Iterable<? extends T> iterable) {
Objects.requireNonNull(iterable, "iterable is null");
if (iterable instanceof Tree) {
return (Tree<T>) iterable;
} else {
final List<T> list = List.ofAll(iterable);
return list.isEmpty() ? Empty.instance() : new Node<>(list.head(), list.tail().map(Tree::of));
}
}
/**
* Returns a new Node containing the given value and having the given children.
*
* @param value A value
* @param children The child nodes, possibly empty
* @param <T> Value type
* @return A new Node instance.
*/
static <T> Node<T> of(T value, Iterable<Node<T>> children) {
Objects.requireNonNull(children, "children is null");
return new Node<>(value, List.ofAll(children));
}