*/
@Experimental
@ThreadSafe
@Provider
public interface SessionData {

    /**
     * Associates the specified session data with the given key.
     *
     * @param key the key under which to store the session data, must not be {@code null}
     * @param value the data to associate with the key, may be {@code null} to remove the mapping
     */
    <T> void set(@Nonnull Key<T> key, @Nullable T value);

    /**

    // In order for the weak hash map to work correctly, we must not hold any reference to
    // the model used as the key.  So we use a dummy model as a placeholder to indicate that
    // we want to store the model used as they key.
    private static final Model KEY = Model.newInstance();

    private final ProfileModelMerger merger = new ProfileModelMerger();

    @Override
    public Model injectProfiles(

            } catch (PluginVersionResolutionException e) {
                throw new PluginManagerException(plugin, e.getMessage(), e);
            }
        }

        // TODO: store plugin version

        // resolve plugin artifacts
        List<Artifact> artifacts;
        PluginArtifactsCache.Key cacheKey = pluginArtifactsCache.createKey(plugin, null, repositories, session);

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

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

/**
 * Provides access to the contents of a source independently of the
 * backing store (e.g. file system, database, memory).
 * <p>
 * This is mainly used to parse files into objects such as
 * {@link org.apache.maven.api.Project},
 * {@link org.apache.maven.api.model.Model},

    /**
     * Gets the relative path for a locally installed artifact. Note that the artifact need not actually exist yet at
     * the returned location, the path merely indicates where the artifact would eventually be stored.
     * <p>
     * Shortcut for {@code getService(LocalArtifactManager.class).getPathForLocalArtitact(...)}.
     *
     * @param artifact the artifact for which to get a local path

 */
public interface Builder {
    //
    // Be nice to whittle this down to Session, maybe add task segments to the session. The session really is
    // the place to store reactor related information.
    //
    void build(
            MavenSession session,
            ReactorContext reactorContext,
            ProjectBuildList projectBuilds,
            List<TaskSegment> taskSegments,

            mergeMetadata(metadata, remoteRepositories, localRepo);
        } catch (RepositoryMetadataStoreException e) {
            throw new RepositoryMetadataResolutionException(
                    "Unable to store local copy of metadata: " + e.getMessage(), e);
        }
    }

    private Date getLocalCopyLastModified(ArtifactRepository localRepository, RepositoryMetadata metadata) {

    }

    @Override
    public void addResource(@Nonnull Project project, @Nonnull ProjectScope scope, @Nonnull Resource resource) {
        // TODO: we should not modify the underlying model here, but resources should be stored
        // TODO: in a separate field in the project, however, that could break v3 plugins
        MavenProject prj = getMavenProject(nonNull(project, "project"));