* @param options The options to use for deserialization, may be {@code null} to use the default values.
     * @return The deserialized metadata, never {@code null}.
     * @throws IOException If the metadata could not be deserialized.
     * @throws MetadataParseException If the input format could not be parsed.
     */

     * artifact files.
     *
     * @param session the {@link Session}, must not be {@code null}
     * @param root the Maven Dependency, must not be {@code null}
     * @return the collection result, never {@code null}
     * @throws DependencyCollectorException if the dependency tree could not be built
     * @throws IllegalArgumentException if an argument is null or invalid

     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_OS2 = "os/2";

    /**
     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_NETWARE = "netware";

    /**
     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_DOS = "dos";

    /**
     * OS family that can be tested for. {@value}
     */

     * {@link org.apache.maven.model.ConfigurationContainer#getConfiguration()} or a similar source.
     * If {@code element} is not {@code null}, child configuration element with the specified name will
     * be unmarshalled.
     *
     * @param configuration The configuration to unmarshal, may be {@code null}.

 * <p>
 * Unlike a cache, this session data is not subject to purging. For this same reason, session data should also not be
 * abused as a cache (i.e. for storing values that can be re-calculated) to avoid memory exhaustion.
 * <p>
 * <strong>Note:</strong> Actual implementations must be thread-safe.
 *
 * @see Session#getData()
 * @since 4.0.0
 */
@Experimental
@ThreadSafe
@Provider

     * @param pluginGroups The list of group ids to scan for the plugin prefix, may be {@code null}.
     * @return This request, never {@code null}.
     */
    PluginPrefixRequest setPluginGroups(List<String> pluginGroups);

    /**
     * Gets the POM whose build plugins are to be scanned for the prefix.
     *
     * @return The POM whose build plugins are to be scanned for the prefix or {@code null} to only search the plugin

 the top of that lineage to provide default values.

 The super model is where we place all the values which we believe to be standard, values that can be shared and
 utilized across all your Maven projects.

+-----+
 m0 <- m1 <- m2
+-----+

 which is transformed into

+-----+
 super model <- m0 <- m1 <- m2
+-----+

+-----+

        return builder()
                .session(nonNull(session, "session cannot be null"))
                .repository(nonNull(repository, "repository cannot be null"))
                .artifacts(nonNull(artifacts, "artifacts cannot be null"))
                .build();
    }

    class ArtifactDeployerRequestBuilder {
        Session session;

// TODO what runs in each phase
// TODO plugins that need downloading
// TODO project dependencies that need downloading
// TODO unfortunately the plugins need to be downloaded in order to get the plugin.xml file. need to externalize this
//      from the plugin archive.
// TODO this will be the class that people get in IDEs to modify

/**
 * MavenExecutionPlan
 */
public class MavenExecutionPlan implements Iterable<ExecutionPlanItem> {

    }

    public static String key(String groupId, String artifactId, String version) {
        notBlank(groupId, "groupId can neither be null, empty nor blank");
        notBlank(artifactId, "artifactId can neither be null, empty nor blank");
        notBlank(version, "version can neither be null, empty nor blank");

        return groupId + ":" + artifactId + ":" + version;
    }