ImmutableMapFactory { public static <K, L, V> ImmutableMap<L, V> createWithNewKeys( Map<K, V> baseMap, Function<? super K, ? extends L> keyMapper) { return create(baseMap, keyMapper, Function.identity()); }  static ImmutableMap<L, W> create(
            Map<K, V> baseMap,
            BiFunction<? super K, ? super V, ? extends L> keyCreator,
            BiFunction<? super K, ? super V, ? extends W> valueCreator); static ImmutableMap<L, W> create(
            Map<K, V> baseMap,
            Function<? super K, ? extends L> keyMapper,
            Function<? super V, ? extends W> valueMapper); static ImmutableMap<L, W> createAndReduceCollisions(
            Map<K, V> baseMap,
            Function<? super K, ? extends L> keyMapper,
            Function<? super V, ? extends W> valueMapper,
            W valueIdentity,
            BinaryOperator<W> collidingKeysAccumulator); static ImmutableMap<L, V> createWithNewKeys(
            Map<K, V> baseMap,
            Function<? super K, ? extends L> keyMapper); static ImmutableMap<K, W> createWithNewValues(
            Map<K, V> baseMap,
            Function<? super V, ? extends W> valueMapper); static ImmutableMap<K, W> createWithNewValues(
            Map<K, V> baseMap,
            BiFunction<? super K, ? super V, ? extends W> valueMapper); static ImmutableMap<K, V> createFromKeys(
            Collection<K> keys,
            Supplier<V> valueSupplier); static ImmutableMap<K, V> createFromKeys(
            Collection<K> keys,
            Function<K, V> valueCreator); static ImmutableMap<K, V> zip(
            List<K> keys,
            List<V> values); static ImmutableMap<K, V> filter(
            Map<K, V> baseMap,
            BiPredicate<K, V> filter); static ImmutableMap<K, V> filterByKeys(
            Map<K, V> baseMap,
            Predicate<K> keyFilter); static ImmutableMap<K, V> filterByValues(
            Map<K, V> baseMap,
            Predicate<V> valueFilter); static ImmutableMap<K, V> parse(
            String s,
            Function<String, K> keyParser,
            Function<String, V> valueParser); static ImmutableMap<K, V> parseAndFilter(
            String s,
            Function<String, K> keyParser,
            Function<String, V> valueParser,
            BiPredicate<K, V> filter);  }
@Test void testCreateWithNewKeys() { ImmutableMap<Integer, Integer> baseMap = ImmutableMap.of( 3, 1, 7, 2, 14, 3, 1, 4); ImmutableMap<Integer, Integer> expected = ImmutableMap.of( 6, 1, 14, 2, 28, 3, 2, 4); ImmutableMap<Integer, Integer> actual = ImmutableMapFactory. createWithNewKeys(baseMap, key -> key * 2); Assertions.assertEquals(expected, actual); }
@Test void testCreateWithNewKeysToADifferentType() { ImmutableMap<Integer, Integer> baseMap = ImmutableMap.of( 3, 1, 7, 2, 14, 3, 1, 4); ImmutableMap<String, Integer> expected = ImmutableMap.of( "3", 1, "7", 2, "14", 3, "1", 4); ImmutableMap<String, Integer> actual = ImmutableMapFactory. createWithNewKeys(baseMap, String::valueOf); Assertions.assertEquals(expected, actual); }