Method map

libs/shared/src/main/java/io/crate/common/collections/Lists.java:156–165

Create a copy of the given list with mapper applied on each item. Opposed to java.util.stream.Stream#map(Function) / Collectors#toList() this minimizes allocations.

(Collection<I> list, Function<? super I, ? extends O> mapper)

     * Opposed to {@link java.util.stream.Stream#map(Function)} / {@link Collectors#toList()} this minimizes allocations.
     */
    public static <I, O> List<O> map(Collection<I> list, Function<? super I, ? extends O> mapper) {
        if (list.isEmpty()) {
            return List.of();
        }
        ArrayList<O> copy = new ArrayList<>(list.size());
        for (I item : list) {
            copy.add(mapper.apply(item));
        }
        return copy;
    }

    /**
     * Like `map` but ensures that the same list is returned if no elements changed.