private static <T> Object[] toArray(Iterable<T> elements) {
if (elements instanceof java.util.List) {
final java.util.List<T> list = (java.util.List<T>) elements;
return list.toArray();
} else {
final java.util.Iterator<? extends T> it = elements.iterator();
final java.util.List<T> list = new java.util.ArrayList<>();
while (it.hasNext()) {
list.add(it.next());
}
return list.toArray();
}
}
@Override
public <U> Array<U> flatMap(Function<? super T, ? extends Iterable<? extends U>> mapper) {
Objects.requireNonNull(mapper, "mapper is null");
if (isEmpty()) {
return empty();
} else {
final java.util.List<U> list = new ArrayList<>();
for (T t : this) {
for (U u : mapper.apply(t)) {
list.add(u);
}
}
return wrap(toArray(list));
}
}
@Override
public Array<T> filter(Predicate<? super T> predicate) {
Objects.requireNonNull(predicate, "predicate is null");
final java.util.List<T> list = new ArrayList<>();
for (T t : this) {
if (predicate.test(t)) {
list.add(t);
}
}
if (list.isEmpty()) {
return empty();
} else if (list.size() == size()) {
return this;
} else {
return wrap(list.toArray());
}
}