*/
    @Nonnull
    String defaultValue() default "";

    /**
     * is the parameter required?
     * @return <code>true</code> if the Mojo should fail when the parameter cannot be injected
     */
    boolean required() default false;

    /**
     * Specifies that this parameter cannot be configured directly by the user (as in the case of POM-specified

    }

    private Stream<String> getParameterNames(Parameter parameter) {
        if (parameter.getAlias() != null) {
            return Stream.of(parameter.getName(), parameter.getAlias());
        } else {
            return Stream.of(parameter.getName());
        }
    }

    private Set<String> getUnknownParameters(MojoExecution mojoExecution, Set<String> parameters) {

 *
 * @since 4.0.0
 */
@Experimental
public interface ArtifactCoordinateFactory extends Service {

    /**
     * Creates a coordinate.
     *
     * @param request the request holding coordinate creation parameters
     * @return an {@code ArtifactCoordinate}, never {@code null}
     * @throws IllegalArgumentException if {@code request} is null or {@code request.session} is null or invalid
     */
    @Nonnull

     * Builds a project descriptor from the specified POM file.
     *
     * @param projectFile The POM file to build the project from, must not be {@code null}.
     * @param request The project building request that holds further parameters, must not be {@code null}.
     * @return The result of the project building, never {@code null}.
     * @throws ProjectBuildingException If the project descriptor could not be successfully built.
     */

            new RequestPomCollectionStrategy(projectsSelector);

    private Map<String, MavenProject> artifactIdProjectMap;

    public static Stream<Arguments> parameters() {
        return Stream.of(
                scenario("Full reactor in order")
                        .expectResult(
                                PARENT_MODULE,
                                MODULE_C,

@Experimental
public interface ToolchainsBuilder extends Service {

    /**
     * Builds the effective toolchains for the specified toolchains files.
     *
     * @param request the toolchains building request that holds the parameters, must not be {@code null}
     * @return the result of the toolchains building, never {@code null}
     * @throws ToolchainsBuilderException if the effective toolchains could not be built
     */

@Experimental
public interface SettingsBuilder extends Service {

    /**
     * Builds the effective settings of the specified settings files.
     *
     * @param request the settings building request that holds the parameters, must not be {@code null}
     * @return the result of the settings building, never {@code null}
     * @throws SettingsBuilderException if the effective settings could not be built
     */
    @Nonnull

            return;
        }

        List<Parameter> invalidParameters = new ArrayList<>();

        for (Parameter parameter : mojoDescriptor.getParameters()) {
            if (!parameter.isRequired()) {
                continue;
            }

            Object value = null;

            PlexusConfiguration config = configuration.getChild(parameter.getName(), false);
            if (config != null) {

     * in which case there is one key per sub-directory.
     *
     * <p>This map may contain null values if the constructor was invoked with {@code resolve}
     * parameter set to false. This is more efficient when only the module existence needs to
     * be tested, and module descriptors are not needed.</p>
     *
     * @see #getModuleNames()
     */

    /**
     * Gets the user properties to use for interpolation and profile activation. The user properties have been
     * configured directly by the user on his discretion, e.g. via the {@code -Dkey=value} parameter on the command
     * line.
     *
     * @return The user properties, never {@code null}.
     */
    Map<String, String> getUserProperties();

    /**