return projects == null ? null : map(projects, this::getProject);
    }

    @Override
    public Project getProject(MavenProject project) {
        return project != null && project.getBasedir() != null
                ? allProjects.computeIfAbsent(project.getId(), id -> new DefaultProject(this, project))
                : null;
    }

    @Override

            request.setLocalRepository(createLocalRepository(request));
        }

        if (request.getLocalRepositoryPath() == null) {
            request.setLocalRepositoryPath(new File(request.getLocalRepository().getBasedir()).getAbsoluteFile());
        }
    }

    // ------------------------------------------------------------------------
    // Artifact Transfer Mechanism

        }

        return sb.toString();
    }

    @Override
    public Artifact find(Artifact artifact) {
        File artifactFile = new File(getBasedir(), pathOf(artifact));

        // We need to set the file here or the resolver will fail with an NPE, not fully equipped to deal
        // with multiple local repository implementations yet.

            throws IOException, XMLStreamException {
        Metadata metadata = null;

        File metadataFile = new File(
                localRepository.getBasedir(), localRepository.pathOfLocalRepositoryMetadata(this, remoteRepository));

        if (metadataFile.length() == 0) {
            if (!metadataFile.delete()) {

    protected static final ConcurrentMap<String, TraverserFactory> traverserFactories = newConcurrentHashMap();
    static {
        addTraverserFactory("file", (url, rootPackage, rootDir) -> new FileSystemTraverser(getBaseDir(url, rootDir), rootPackage, rootDir));
        addTraverserFactory("jar", JarFileTraverser::new);
        addTraverserFactory("zip", (url, rootPackage,

        return result;
    }

    @Override
    public void updateVersion(String version, ArtifactRepository localRepository) {
        setResolvedVersion(version);
        setFile(new File(localRepository.getBasedir(), localRepository.pathOf(this)));
    }

    @Override
    public String getDownloadUrl() {
        return downloadUrl;
    }

    @Override
    public void setDownloadUrl(String downloadUrl) {

        this.properties = session.getEffectiveProperties(project);
        this.project = project;

        Path basedir = null;

        if (project != null) {
            Path projectFile = project.getBasedir();
            basedir = projectFile.toAbsolutePath();
        }

        if (basedir == null) {
            basedir = session.getTopDirectory();
        }

        if (basedir == null) {

        this.properties.putAll(session.getSystemProperties());

        String basedir = null;

        if (project != null) {
            File projectFile = project.getBasedir();

            // this should always be the case for non-super POM instances...
            if (projectFile != null) {
                basedir = projectFile.getAbsolutePath();
            }
        }

                    .filter(p -> p != null && !p.trim().isEmpty())
                    .map(this::resolve)
                    .forEach(paths::add);
        }
        paths.add(Paths.get(request.getLocalRepository().getBasedir()));
        String localRepoTail = mergedProps.get(Constants.MAVEN_REPO_LOCAL_TAIL);
        if (localRepoTail != null) {
            Arrays.stream(localRepoTail.split(","))

        this.localRepository = localRepository;

        if (localRepository != null) {
            setLocalRepositoryPath(new File(localRepository.getBasedir()).getAbsoluteFile());
        }

        return this;
    }

    @Override
    public MavenExecutionRequest setLocalRepositoryPath(File localRepository) {
        localRepositoryPath = localRepository;