}

    private Optional<String> extractRequiredJavaVersion(PlexusConfiguration c) {
        return Optional.ofNullable(c.getChild("requiredJavaVersion")).map(PlexusConfiguration::getValue);
    }

    private Optional<String> extractRequiredMavenVersion(PlexusConfiguration c) {
        return Optional.ofNullable(c.getChild("requiredMavenVersion")).map(PlexusConfiguration::getValue);
    }

            @Nonnull
            @Override
            public Optional<Path> getPath() {
                return Optional.ofNullable(path);
            }

            @Nonnull
            @Override
            public Optional<Source> getSource() {
                return Optional.ofNullable(source);
            }

            @Override
            public boolean isAllowStubModel() {

            @Nonnull
            @Override
            public Optional<Project> getProject() {
                return Optional.ofNullable(project);
            }

            @Nonnull
            @Override
            public Optional<Artifact> getRootArtifact() {
                return Optional.ofNullable(rootArtifact);
            }

            @Nonnull
            @Override

        if (artifact == null) {
            return null;
        }

        Artifact result = toArtifact(artifact);

        List<Exclusion> excl = Optional.ofNullable(exclusions).orElse(Collections.emptyList()).stream()
                .map(RepositoryUtils::toExclusion)
                .collect(Collectors.toList());

                                    path = defaultArtifact.getArtifact().getPath();
                                }
                                return Optional.ofNullable(path);
                            }

                            @Override
                            public void setPath(ProducedArtifact artifact, Path path) {

     *
     * @return the {@code javax.tool} enumeration value corresponding to this {@code JavaPathType}
     */
    public Optional<JavaFileManager.Location> location() {
        return Optional.ofNullable(location);
    }

    /**
     * Returns the path type associated to the given {@code javax.tool} location.
     * This method is the converse of {@link #location()}.
     *

                @Override
                public Optional<org.apache.maven.api.Toolchain> createDefaultToolchain()
                        throws ToolchainFactoryException {
                    return Optional.ofNullable(v3Factory.createDefaultToolchain())
                            .map(ToolchainManagerFactory.this::getToolchainV4);
                }
            });
        }
        allFactories.putAll(v4Factories);

        return OptionalUtil.ofNullable(webConfig);
    }

    /**
     * Gets the file crawling configuration generated from the parsed GSA config.
     *
     * @return an optional containing the file configuration, or empty if no file URLs were found
     */
    public OptionalEntity<FileConfig> getFileConfig() {
        return OptionalUtil.ofNullable(fileConfig);
    }

    /**

   * reference; otherwise returns {@link Optional#absent}.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method is equivalent to Java 8's
   * {@code Optional.ofNullable}.
   */
  public static <T> Optional<T> fromNullable(@Nullable T nullableReference) {
    return (nullableReference == null) ? Optional.<T>absent() : new Present<T>(nullableReference);
  }

  /**

        // Session keep tracks of the Project per project id,
        // so we cannot use session.getProject(p) for forked projects
        // which are temporary clones
        return Optional.ofNullable(getMavenProject(project).getExecutionProject())
                .map(p -> new DefaultProject(session, p));
    }

    private MavenProject getMavenProject(Project project) {