val shadowPackagePrefix =
        shadowPackage.takeIf(String::isNotEmpty)
            ?.let { it.replace('.', '/') + "/" }
            ?: ""

    operator fun get(className: String) =
        classes.computeIfAbsent(className) {
            val outputClassName = if (unshadedPackages.matches(className)) className else shadowPackagePrefix + className
            ClassDetails(outputClassName).also { classDetails ->

     *
     * @see Function
     * @see Optional
     * @see HashMap#computeIfAbsent(Object, Function)
     */
    static Function<String, String> memoize(Function<String, String> callback) {
        Map<String, Optional<String>> cache = new HashMap<>();
        return s -> cache.computeIfAbsent(s, v -> Optional.ofNullable(callback.apply(v)))
                .orElse(null);
    }

    public DefaultSuperPomProvider(ModelProcessor modelProcessor) {
        this.modelProcessor = modelProcessor;
    }

    @Override
    public Model getSuperModel(String version) {
        return SUPER_MODELS.computeIfAbsent(Objects.requireNonNull(version), v -> {
            String resource = "/org/apache/maven/model/pom-" + v + ".xml";

            InputStream is = getClass().getResourceAsStream(resource);

            if (is == null) {

@Deprecated(since = "4.0.0")
class Graph {

    final Map<String, Set<String>> graph = new LinkedHashMap<>();

    synchronized void addEdge(String from, String to) throws CycleDetectedException {
        if (graph.computeIfAbsent(from, l -> new HashSet<>()).add(to)) {
            List<String> cycle = visitCycle(graph, Collections.singleton(to), new HashMap<>(), new LinkedList<>());
            if (cycle != null) {

        vFrom.setCompareScope(scopedVertices);

        List<MetadataGraphEdge> exList = excidentEdges.computeIfAbsent(vFrom, k -> new ArrayList<>());

        if (!exList.contains(e)) {
            exList.add(e);
        }

        List<MetadataGraphEdge> inList = incidentEdges.computeIfAbsent(vTo, k -> new ArrayList<>());

        if (!inList.contains(e)) {
            inList.add(e);
        }

    public Optional<Type> lookup(String id) {
        return Optional.of(require(id));
    }

    @Override
    @Nonnull
    public Type require(String id) {
        nonNull(id, "id");
        return usedTypes.computeIfAbsent(id, i -> {
            Type type = types.get(id);
            if (type == null) {
                // Copy data as the ArtifactHandler is not immutable, but Type should be.

                allHandlers.clear();
            }
        }
    }

    @Override
    public ArtifactHandler getArtifactHandler(String id) {
        return allHandlers.computeIfAbsent(id, k -> {
            Type type = typeRegistry.require(id);
            return new DefaultArtifactHandler(
                    id,
                    type.getExtension(),
                    type.getClassifier(),

        return vertices.get(id);
    }

    public Collection<Vertex> getVertices() {
        return vertices.values();
    }

    Vertex addVertex(String label) {
        return vertices.computeIfAbsent(label, Vertex::new);
    }

    void addEdge(Vertex from, Vertex to) throws CycleDetectedException {
        from.children.add(to);
        to.parents.add(from);
        List<String> cycle = findCycle(to);

                            // Ignore
                        }
                    }
                }
            }
            return model;
        }

        public Model computeIfAbsent(Supplier<Model> supplier) {
            if (!set) {
                synchronized (this) {
                    if (!set) {
                        this.set = true;
                        this.model = supplier.get();

        lifecycle.allPhases().forEach(phase -> phase.plugins()
                .forEach(plugin -> plugin.getExecutions().forEach(exec -> exec.getGoals()
                        .forEach(goal -> goals.computeIfAbsent(phase.name(), n -> new ArrayList<>())
                                .add(plugin.getGroupId() + ":" + plugin.getArtifactId() + ":" + plugin.getVersion()
                                        + ":" + goal)))));