*
     * @return The problems that caused this exception, never {@code null}.
     */
    public List<ModelProblem> getProblems() {
        if (result == null) {
            return Collections.emptyList();
        }
        return Collections.unmodifiableList(result.getProblems());
    }

     */
    PersistedToolchains getEffectiveToolchains();

    /**
     * Return a list of problems, if any.
     *
     * @return a list of problems, never {@code null}.
     */
    List<Problem> getProblems();

/**
 * Defines events that the model builder fires during construction of the effective model. When a listener encounters
 * errors while processing the event, it can report these problems via {@link ModelBuildingEvent#getProblems()}.
 * Note: To cope with future extensions to this interface, it is strongly recommended to extend
 * {@link AbstractModelBuildingListener} rather than to directly implement this interface.
 *

        this.activeExternalProfiles.addAll(result.getActiveExternalProfiles());
        this.effectiveModel = result.getEffectiveModel();
        this.fileModel = result.getFileModel();
        this.problems.addAll(result.getProblems());

        for (String modelId : result.getModelIds()) {
            this.modelIds.add(modelId);
            this.rawModels.put(modelId, result.getRawModel(modelId));

    public Model getModel() {
        return model;
    }

    @Override
    public ModelBuildingRequest getRequest() {
        return request;
    }

    @Override
    public ModelProblemCollector getProblems() {
        return problems;
    }

                }

                @Nonnull
                @Override
                public Collection<BuilderProblem> getProblems() {
                    return new MappedCollection<>(res.getProblems(), this::toProblem);
                }

                private BuilderProblem toProblem(ModelProblem problem) {
                    return new BuilderProblem() {

     *
     * @param source a source
     */
    void setSource(String source);

    /**
     *
     * @return the collected Problems, never {@code null}
     */
    List<Problem> getProblems();

        }
    }

    /**
     * Gets the problems that caused this exception.
     *
     * @return The problems that caused this exception, never {@code null}.
     */
    public List<Problem> getProblems() {
        return problems;
    }

    private static String toMessage(List<Problem> problems) {
        StringWriter buffer = new StringWriter(1024);

        PrintWriter writer = new PrintWriter(buffer);

                    .build());

            return new DefaultSettingsBuildingResult(
                    new Settings(result.getEffectiveSettings()), convert(result.getProblems()));
        } catch (SettingsBuilderException e) {
            throw new SettingsBuildingException(convert(e.getProblems()));
        }
    }

    private org.apache.maven.api.services.Source toSource(File file, Source source) {
        if (file != null && file.exists()) {

 *
 */
public interface ModelProblemCollector {

    /**
     * The collected problems.
     * @return a list of model problems encountered, never {@code null}
     */
    List<ModelProblem> getProblems();

    boolean hasErrors();

    boolean hasFatalErrors();

    default void add(BuilderProblem.Severity severity, ModelProblem.Version version, String message) {