private <K> FunctionalMultiMap<K, T> groupIntoMap(
final FunctionalMultiMap<K, T> map,
final Function<T, K> groupingFunction,
FunctionalList<T> values) {
return values.isEmpty()
? map
: groupIntoMap(
map.put(groupingFunction.apply(values.head()), values.head()),
groupingFunction,
values.tail());
}
public T firstMatch(final Function<T, Boolean> matcher) {
return isEmpty() ? null : matcher.apply(head()) ? head() : tail().firstMatch(matcher);
}
public FunctionalList<T> dropWhile(final Function<T, Boolean> condition) {
return isEmpty() ? this : condition.apply(head()) ? tail().dropWhile(condition) : this;
}
public <U> FunctionalList<U> map(final Function<T, U> mapping) {
return isEmpty() ? FunctionalList.<U>nil() : cons(mapping.apply(head()), tail().map(mapping));
}