}

    /**
     * Mark a profile as required and activated.
     * @param id The identifier of the profile.
     */
    public void activateRequiredProfile(String id) {
        this.activations.put(id, ActivationSettings.ACTIVATION_REQUIRED);
    }

    /**
     * Mark a profile as optional and activated.
     * @param id The identifier of the profile.
     */
    public void activateOptionalProfile(String id) {

        return model;
    }

    /**
     * Gets the effective group identifier of the model.
     *
     * @return The effective group identifier of the model or an empty string if unknown, never {@code null}.
     */
    public String getGroupId() {
        return (groupId != null) ? groupId : "";
    }

    /**
     * Gets the effective artifact identifier of the model.
     *

  // Audiences are audience identifiers chosen by the authenticator that are
  // compatible with both the TokenReview and token. An identifier is any
  // identifier in the intersection of the TokenReviewSpec audiences and the
  // token's audiences. A client of the TokenReview API that sets the
  // spec.audiences field should validate that a compatible audience identifier

  // Audiences are audience identifiers chosen by the authenticator that are
  // compatible with both the TokenReview and token. An identifier is any
  // identifier in the intersection of the TokenReviewSpec audiences and the
  // token's audiences. A client of the TokenReview API that sets the
  // spec.audiences field should validate that a compatible audience identifier

 * </p>
 *
 * @since 4.0.0
 */
@Experimental
@Immutable
public interface Artifact {
    /**
     * {@return a unique identifier for this artifact}
     * The identifier is composed of groupId, artifactId, extension, classifier, and version.
     *
     * @see ArtifactCoordinates#getId()
     */
    @Nonnull
    default String key() {

    /**
     * Gets the sequence of model identifiers that denote the lineage of models from which the effective model was
     * constructed. Model identifiers should be handled as "opaque strings" and this method should be used as source
     * if navigating the linage. The first identifier from the list denotes the model on which the model builder
     * was originally invoked. The last identifier will always be the super POM.
     *

   * identifier} as the bus's name for logging purposes.
   *
   * @param identifier short name for the bus, for logging purposes.
   * @param executor Executor to use to dispatch events. It is the caller's responsibility to shut
   *     down the executor after the last event has been posted to this event bus.
   */
  public AsyncEventBus(String identifier, Executor executor) {

    }

    /**
     * Gets the identifier of the POM whose effective model could not be built. The general format of the identifier is
     * {@code <groupId>:<artifactId>:<version>} but some of these coordinates may still be unknown at the point the
     * exception is thrown so this information is merely meant to assist the user.
     *
     * @return The identifier of the POM or an empty string if not known, never {@code null}.

    // --------------------------/
    // - Class/Member Variables -/
    // --------------------------/

    /**
     *
     *
     *             The identifier of the POM in the format {@code
     * <groupId>:<artifactId>:<version>}.
     *
     *
     */
    private String modelId;

    /**
     *
     *

      <description>Definition of a toolchain instance.</description>
      <fields>
        <field>
          <name>type</name>
          <version>1.0.0+</version>
          <!-- <identifier>true</identifier> -->
          <description>
            Type of toolchain:&lt;ul>
            &lt;li>{@code jdk} for &lt;a