Map merge()

in bval-jsr/src/main/java/org/apache/bval/jsr/metadata/DualBuilder.java [80:110]

• 27 lines of code
• 7 McCabe index (conditional complexity)

        <K, D> Map<K, D> merge(Function<DELEGATE, Map<K, D>> toMap, BiFunction<D, D, D> parallel,
            Supplier<D> emptyBuilder) {

            final Map<K, D> primaries = toMap.apply(primaryDelegate);
            final Map<K, D> customs = toMap.apply(customDelegate);

            if (primaries.isEmpty() && customs.isEmpty()) {
                return Collections.emptyMap();
            }

            final Function<? super K, ? extends D> valueMapper = k -> {
                final D primary = primaries.get(k);
                final D custom = customs.get(k);

                if (custom == null) {
                    if (primary != null) {
                        switch (getCustomAnnotationBehavior()) {
                        case INCLUDE:
                        case ABSTAIN:
                            return primary;
                        default:
                            break;
                        }
                    }
                    return emptyBuilder.get();
                }
                return parallel.apply(primary, custom);
            };
            return Stream.of(primaries, customs).map(Map::keySet).flatMap(Collection::stream).distinct()
                .collect(Collectors.toMap(Function.identity(), valueMapper));
        }