@Nonnull
    String getName();

    @Nonnull
    String getNamespaceUri();

    @Nonnull
    String getPrefix();

    @Nullable
    String getValue();

    @Nonnull
    Map<String, String> getAttributes();

    @Nullable
    String getAttribute(@Nonnull String name);

    @Nonnull
    List<XmlNode> getChildren();

    @Nullable

     */
    @Nonnull
    List<Toolchain> getToolchains(@Nonnull Session session, String type, Map<String, String> requirements);

    /**
     *
     * @param session
     * @param type
     * @return the selected {@link Toolchain}
     * @throws ToolchainManagerException if an exception occurs
     */
    @Nonnull

     * @throws ParserException if there's an error during parsing of the request
     * @throws IOException if there's an I/O error during the parsing process
     */
    @Nonnull
    R parse(@Nonnull ParserRequest parserRequest) throws ParserException, IOException;

     * @throws DependencyResolverException
     */
    List<Node> flatten(@Nonnull Session session, @Nonnull Node node, @Nullable PathScope scope)
            throws DependencyResolverException;

    @Nonnull
    default DependencyResolverResult flatten(
            @Nonnull Session session, @Nonnull Project project, @Nonnull PathScope scope) {
        return flatten(DependencyResolverRequest.build(

                    Arrays.spliterator(new String[] {"abc", "", "de", "f", "g", ""}),
                    (String str) -> charactersOf(str).spliterator(),
                    Spliterator.SIZED | Spliterator.DISTINCT | Spliterator.NONNULL,
                    7))
        .expect('a', 'b', 'c', 'd', 'e', 'f', 'g');
  }

  public void testFlatMap_nullStream() {
    SpliteratorTester.of(
            () ->
                CollectSpliterators.flatMap(

        String CLEAN = "clean";

        @Nonnull
        String name();

        @Nonnull
        List<Plugin> plugins();

        @Nonnull
        Collection<Link> links();

        /**
         * {@return the list of sub-phases}
         */
        @Nonnull
        List<Phase> phases();

        @Nonnull
        Stream<Phase> allPhases();
    }

    /**

                .coordinates(nonNull(coordinates, "coordinates cannot be null"))
                .build();
    }

    @Nonnull
    static ArtifactResolverRequest build(
            @Nonnull Session session,
            @Nonnull Collection<? extends ArtifactCoordinates> coordinates,
            List<RemoteRepository> repositories) {
        return builder()

    int getRetryFailedDeploymentCount();

    @Nonnull
    static ArtifactDeployerRequestBuilder builder() {
        return new ArtifactDeployerRequestBuilder();
    }

    @Nonnull
    static ArtifactDeployerRequest build(
            @Nonnull Session session,
            @Nonnull RemoteRepository repository,
            @Nonnull Collection<ProducedArtifact> artifacts) {
        return builder()

     */
    @Nonnull
    String getGroupId();

    /**
     * {@return the identifier of the artifact}
     */
    @Nonnull
    String getArtifactId();

    /**
     * Returns the classifier of the artifact.
     *
     * @return the classifier or an empty string if none, never {@code null}
     */
    @Nonnull
    String getClassifier();

    /**

    @Nonnull
    static VersionResolverRequest build(@Nonnull Session session, @Nonnull ArtifactCoordinates artifactCoordinates) {
        return builder()
                .session(nonNull(session, "session cannot be null"))
                .artifactCoordinates(nonNull(artifactCoordinates, "artifactCoordinates cannot be null"))
                .build();
    }

    @Nonnull
    static VersionResolverRequest build(