String id = repo.getId();

            if (id == null || id.isEmpty()) {
                throw new InvalidRepositoryException("Repository identifier missing", "");
            }

            String url = repo.getUrl();

            if (url == null || url.isEmpty()) {
                throw new InvalidRepositoryException("URL missing for repository " + id, id);
            }

    }

    private ArtifactSpec createArtifactSpec(String id, String version) throws InvalidVersionSpecificationException {
        return createArtifactSpec(id, version, Artifact.SCOPE_COMPILE);
    }

    private ArtifactSpec createArtifactSpec(String id, String version, boolean optional)
            throws InvalidVersionSpecificationException {
        return createArtifactSpec(id, version, Artifact.SCOPE_COMPILE, null, optional);
    }

          </configuration>
          <executions>
            <execution>
              <id>site-docs</id>
              <phase>pre-site</phase>
              <goals>
                <goal>xdoc</goal>
                <goal>xsd</goal>
              </goals>
            </execution>
            <execution>
              <id>standard</id>
              <goals>
                <goal>java</goal>

          </configuration>
          <executions>
            <execution>
              <id>site-docs</id>
              <phase>pre-site</phase>
              <goals>
                <goal>xdoc</goal>
                <goal>xsd</goal>
              </goals>
            </execution>
            <execution>
              <id>standard</id>
              <goals>
                <goal>java</goal>

    </mailingList>
  </mailingLists>

  <developers>
    <developer>
      <id>jvanzyl</id>
      <name>Jason van Zyl</name>
      <email>******@****.***</email>
      <organization>ASF</organization>
      <roles>
        <role>PMC Chair</role>
      </roles>
      <timezone>-5</timezone>
    </developer>
    <developer>
      <id>brett</id>
      <name>Brett Porter</name>
      <email>******@****.***</email>

    /**
     * Obtain the {@link Type} from the specified {@code id}.
     * <p>
     * Shortcut for {@code getService(TypeRegistry.class).require(...)}.
     *
     * @see org.apache.maven.api.services.TypeRegistry#require(String)
     */
    @Nonnull
    Type requireType(@Nonnull String id);

    /**
     * Obtain the {@link Language} from the specified {@code id}.
     * <p>

    }

    public String getId() {
        return id;
    }

    public String getUrl() {
        return url;
    }

    public String getBasedir() {
        return basedir;
    }

    public String getProtocol() {
        return protocol;
    }

    public void setId(String id) {
        this.id = id;
    }

    public void setUrl(String url) {

                null /* artifacts */);

        this.providedArtifacts = exports.getExportedArtifacts();
    }

    private ClassRealm newRealm(String id) {
        synchronized (world) {
            String realmId = id;

            Random random = new Random();

            while (true) {
                try {
                    ClassRealm classRealm = world.newRealm(realmId, null);

    }

    public ArtifactRepository createArtifactRepository(
            String id,
            String url,
            ArtifactRepositoryLayout repositoryLayout,
            ArtifactRepositoryPolicy snapshots,
            ArtifactRepositoryPolicy releases) {
        return new MavenArtifactRepository(id, url, repositoryLayout, snapshots, releases);
    }

    public Artifact createArtifactWithClassifier(

        return sortedProjects.size() > 1;
    }

    public List<String> getDependents(String id) {
        return graph.getVertex(id).getParents().stream().map(Vertex::getLabel).collect(Collectors.toList());
    }

    public List<String> getDependencies(String id) {
        return graph.getVertex(id).getChildren().stream().map(Vertex::getLabel).collect(Collectors.toList());
    }