/**
* Creates a Tree of the given elements.
*
* @param <T> Component type of the List.
* @param values Zero or more values.
* @return A Tree containing the given values.
* @throws NullPointerException if {@code values} is null
*/
@SuppressWarnings("varargs")
@SafeVarargs
static <T> Tree<T> of(T... values) {
Objects.requireNonNull(values, "values is null");
List<T> list = List.of(values);
return list.isEmpty() ? Empty.instance() : new Node<>(list.head(), list.tail().map(Tree::of));
}
/**
* 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));
}
}
@SuppressWarnings("unchecked")
@Override
default <T1, T2, T3> Tuple3<Tree<T1>, Tree<T2>, Tree<T3>> unzip3(
Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper) {
Objects.requireNonNull(unzipper, "unzipper is null");
if (isEmpty()) {
return Tuple.of(Empty.instance(), Empty.instance(), Empty.instance());
} else {
return (Tuple3<Tree<T1>, Tree<T2>, Tree<T3>>) (Object) Unzip.apply3((Node<T>) this, unzipper);
}
}
@Override
default Tree<T> replace(T currentElement, T newElement) {
if (isEmpty()) {
return Empty.instance();
} else {
return Replace.apply((Node<T>) this, currentElement, newElement);
}
}
@Override
default <U> Tree<Tuple2<T, U>> zip(Iterable<U> that) {
Objects.requireNonNull(that, "that is null");
if (isEmpty()) {
return Empty.instance();
} else {
return Zip.apply((Node<T>) this, that.iterator());
}
}
@SuppressWarnings("unchecked")
static <T, U> Tree<Tuple2<T, U>> apply(Node<T> node, java.util.Iterator<U> that) {
if (!that.hasNext()) {
return Empty.instance();
} else {
final Tuple2<T, U> value = Tuple.of(node.getValue(), that.next());
final List<Node<Tuple2<T, U>>> children =
(List<Node<Tuple2<T, U>>>)
(Object)
node.getChildren().map(child -> Zip.apply(child, that)).filter(Tree::isDefined);
return new Node<>(value, children);
}
}
/**
* Returns the singleton empty tree.
*
* @param <T> Type of tree values.
* @return The empty tree.
*/
static <T> Empty<T> empty() {
return Empty.instance();
}
@Override
default <U> Tree<U> map(Function<? super T, ? extends U> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
return isEmpty() ? Empty.instance() : TreeModule.Map.apply((Node<T>) this, mapper);
}