@Nullable
    <T> T computeIfAbsent(@Nonnull Key<T> key, @Nonnull Supplier<T> supplier);

    /**
     * Create a key using the given class as an identifier and as the type of the object.
     */
    static <T> Key<T> key(Class<T> clazz) {
        return new Key<>(clazz, clazz);
    }

    /**
     * Create a key using the given class and id.
     */
    static <T> Key<T> key(Class<T> clazz, Object id) {

@Experimental
public interface TypeRegistry extends ExtensibleEnumRegistry<Type> {

    /**
     * Obtain the {@link Type} from the specified {@code id}.
     * If no type is known for {@code id}, the registry will
     * create a custom {@code Type} for it.
     *
     * @param id the id of the type to retrieve
     * @return the type
     */
    @Nonnull
    @Override
    default Type require(@Nonnull String id) {

    // it's all encapsulated here so it appears normalized to the POM builder.

    // We are going to take the project packaging and find all plugin in the default lifecycle and create
    // fully populated Plugin objects, including executions with goals and default configuration taken
    // from the plugin.xml inside a plugin.
    //

     * local repository manager needs to be configured to make session be able to create session instance.
     *
     * @return SessionBuilder configured with minimally required things for "Maven-based resolution". At least LRM must
     * be set on builder to make it able to create session instances.
     */
    @Override
    public SessionBuilder get() {

import org.apache.maven.api.Session;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.model.Repository;

/**
 * Factory service to create {@link LocalRepository} or {@link RemoteRepository} objects.
 *
 * @since 4.0.0
 */
@Experimental
public interface RepositoryFactory extends Service {

    @Nonnull

@Named
@Singleton
public class DefaultDependencyCoordinateFactory implements DependencyCoordinateFactory {

    @Nonnull
    @Override
    public DependencyCoordinate create(@Nonnull DependencyCoordinateFactoryRequest request) {
        nonNull(request, "request");
        InternalSession session = InternalSession.from(request.getSession());

        ArtifactType type = null;

    The Apache projects are characterized by a collaborative, consensus based development process, an open and
    pragmatic software license, and a desire to create high quality software that leads the way in its field.
    We consider ourselves not simply a group of projects sharing a server, but rather a community of developers
    and users.
  </description>
  <licenses>
    <license>

        if (metadata == null) {
            metadata = this.metadata;

            changed = true;
        } else {
            changed = metadata.merge(this.metadata);
        }

        // beware meta-versions!
        String version = metadata.getVersion();
        if (Artifact.LATEST_VERSION.equals(version) || Artifact.RELEASE_VERSION.equals(version)) {

                        rr.getPolicy(true).getUpdatePolicy(),
                        rr.getPolicy(false).getChecksumPolicy());

            } catch (Exception e) {
                throw new RuntimeException("Unable to create repository", e);
            }
        } else {
            // TODO
            throw new UnsupportedOperationException("Not yet implemented");
        }
    }

import static org.apache.maven.internal.impl.Utils.nonNull;

@Named
@Singleton
public class DefaultArtifactFactory implements ArtifactFactory {
    @Override
    public Artifact create(@Nonnull ArtifactFactoryRequest request) {
        nonNull(request, "request");
        InternalSession session = InternalSession.from(request.getSession());
        ArtifactType type = null;