is the location of a file that needs to exist, and if it doesn't, the profile will be
        activated. On the other hand, {@code exists} will test for the existence of the file and if it is
        there, the profile will be activated.
        <p>Variable interpolation for these file specifications is limited to {@code ${project.basedir}},

    /**
     * Aggregating mojo executions (possibly) modify all MavenProjects, including those that are currently in use
     * by concurrently running mojo executions. To prevent race conditions, an aggregating execution will block
     * all other executions until finished.
     * We also lock on a given project to forbid a forked lifecycle to be executed concurrently with the project.

 */
@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) {

import org.apache.maven.api.annotations.Nullable;

import static org.apache.maven.api.services.BaseRequest.nonNull;

/**
 * A Source specific to load POMs.  The {@link #resolve(ModelLocator, String)} method
 * will be used to find POMs for children modules.
 *
 * @since 4.0.0
 */
public interface ModelSource extends Source {

    interface ModelLocator {
        /**

            // even before the arguments from the command line are parsed.  Any exception
            // that would happen here should cause the build to fail at a later stage
            // (when actually parsing the POM) and will lead to a better exception being
            // displayed to the user, so just bail out and return false.
        }
        return false;
    }

    /**
     * Retrieve of compute the data associated with the specified key.
     *
     * @param key the key for which to retrieve the session data, must not be {@code null}
     * @param supplier the supplier will compute the new value
     * @return the session data associated with the key
     */
    @Nullable
    <T> T computeIfAbsent(@Nonnull Key<T> key, @Nonnull Supplier<T> supplier);

    /**

     * coordinates.
     *
     * @param artifact the artifact to add or replace.
     * @deprecated Please use {@link MavenProjectHelper}
     * @throws DuplicateArtifactAttachmentException will never happen but leave it for backward compatibility
     */
    public void addAttachedArtifact(Artifact artifact) throws DuplicateArtifactAttachmentException {
        // if already there we remove it and add again

import org.apache.maven.api.settings.Settings;

/**
 * The session to install / deploy / resolve artifacts and dependencies.
 *
 * TODO: move the remote repositories in the requests (plugins will need to access this list somehow)
 * TODO: add request trace so that requests can be linked together and through the resolver
 * TODO: add a Request interface holding session + parent request
 *
 * @since 4.0.0
 */

        }
    }

    /**
     * Wraps an object, providing reflective access to the object graph of which the
     * supplied object is the root. Expressions like 'child.name' will translate into
     * 'rootObject.getChild().getName()' for non-boolean properties, and
     * 'rootObject.getChild().isName()' for boolean properties.
     */

        if (!VALID_MODEL_VERSIONS.contains(superModelVersion)) {
            // Maven 3.x is always using 4.0.0 version to load the supermodel, so
            // do the same when loading a dependency.  The model validator will also
            // check that field later.
            superModelVersion = "4.0.0";
        }
        ModelData superData = new ModelData(null, getSuperModel(superModelVersion));

        // profile activation