private List<Proxy> proxies;

    private List<SettingsProblem> problems;

    DefaultSettingsDecryptionResult(List<Server> servers, List<Proxy> proxies, List<SettingsProblem> problems) {
        this.servers = (servers != null) ? servers : new ArrayList<>();
        this.proxies = (proxies != null) ? proxies : new ArrayList<>();
        this.problems = (problems != null) ? problems : new ArrayList<>();
    }

    @Override

            final DefaultModelBuildingResult result,
            DefaultModelProblemCollector problems)
            throws ModelBuildingException {
        Model inputModel = readRawModel(request, problems);
        if (problems.hasFatalErrors()) {
            throw problems.newModelBuildingException();
        }

        problems.setRootModel(inputModel);

        model.update(mergeDuplicates(model.getDelegate(), request, problems));
    }

    @Override
    public void injectDefaultValues(
            org.apache.maven.model.Model model, ModelBuildingRequest request, ModelProblemCollector problems) {
        model.update(injectDefaultValues(model.getDelegate(), request, problems));
    }

    @Override

                    return defaultModelBuilder.readRawModel(req, problems);
                } catch (ModelBuildingException e) {
                    // gathered with problem collector
                }
                return null;
            }
        };
    }

    private boolean addEdge(Path from, Path p, DefaultModelProblemCollector problems) {
        try {
            dag.addEdge(from.toString(), p.toString());

     *
     * @return The assembled toolchains, never {@code null}.
     */
    PersistedToolchains getEffectiveToolchains();

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

    /**
     * The default implementation is not visible, create it with this factory
     *
     * @param problems starting set of problems, may be {@code null}
     * @return a new instance of a ProblemCollector
     */
    public static ProblemCollector newInstance(List<Problem> problems) {
        return new DefaultProblemCollector(problems);
    }

    Settings getEffectiveSettings();

    /**
     * Gets the problems that were encountered during the settings building. Note that only problems of severity
     * {@link SettingsProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link SettingsBuildingException}.
     *

     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */
    default void validateFileModel(Model model, ModelBuildingRequest request, ModelProblemCollector problems) {
        // do nothing
    }

    /**

import java.util.List;

/**
 * Collects problems that are encountered during settings building.
 *
 */
public interface ProblemCollector {

    /**
     * Adds the specified problem.
     * Either message or exception is required
     *
     * @param severity The severity of the problem, must not be {@code null}.
     * @param message The detail message of the problem, may be {@code null}.

    Settings getEffectiveSettings();

    /**
     * Gets the problems that were encountered during the settings building. Note that only problems of severity
     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link SettingsBuilderException}.
     *