}

    /**
     * Copy packaged and attached artifacts from this project to the
     * project local repository.
     * This allows a subsequent build to resume while still being able
     * to locate attached artifacts.
     *
     * @param project the project to copy artifacts from
     */
    private void installIntoProjectLocalRepository(MavenProject project) {
        if ("pom".equals(project.getPackaging())

     * @throws IllegalStateException if multiple versions of the same GA are part of the reactor
     */
    Model getRawModel(Path from, String groupId, String artifactId);

    /**
     * Locate the POM file inside the given directory.
     */
    Path locate(Path path);

                }
            }

            @Override
            public <T> T lookup(Class<T> type, String name) {
                try {
                    return injector.getInstance(Key.of(type, name));
                } catch (DIException e) {
                    throw new MavenException("Unable to locate instance of type " + type, e);

        DefaultModelProblemCollector problems = (DefaultModelProblemCollector) collector;
        return new ModelTransformerContext() {

            @Override
            public Path locate(Path path) {
                return context.locate(path);
            }

            @Override
            public String getUserProperty(String key) {
                return context.userProperties.computeIfAbsent(

    @Override
    public Model getRawModel(Path from, String groupId, String artifactId) {
        return Holder.deref(modelByGA.get(new GAKey(groupId, artifactId)));
    }

    @Override
    public Path locate(Path path) {
        return modelLocator.locateExistingPom(path);
    }

    static class GAKey {
        private final String groupId;
        private final String artifactId;

     *
     * @param dir the directory to locate the pom for, never {@code null}
     * @return a {@code Source} pointing to the located pom or an empty {@code Optional} if none was found by this parser
     */
    @Nonnull
    Optional<Source> locate(@Nonnull Path dir);

    /**
     * Parse the model obtained previously by a previous call to {@link #locate(Path)}.
     *

 */
package org.apache.maven.api.services.model;

import java.nio.file.Path;

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

/**
 * Interface used to locate the root directory for a given project.
 *
 * The root locator is usually looked up from the plexus container.
 * One notable exception is the computation of the early {@code session.rootDirectory}

        // Note that the ModelProcessor#locatePom never returns null
        // while the ModelParser#locatePom needs to return an existing path!
        Path pom = modelParsers.stream()
                .map(m -> m.locate(projectDirectory)
                        .map(org.apache.maven.api.services.Source::getPath)
                        .orElse(null))
                .filter(Objects::nonNull)
                .findFirst()

        Path pomPath = pomFile.resolveSibling(relativePath).normalize();
        if (Files.isDirectory(pomPath)) {
            pomPath = context.locate(pomPath);
        }

        if (pomPath == null || !Files.isRegularFile(pomPath)) {
            return Optional.empty();
        }