001/*
002 * SPDX-FileCopyrightText: none
003 * SPDX-License-Identifier: CC0-1.0
004 */
005
006package dev.metaschema.oscal.lib.model.control.catalog;
007
008import java.util.Objects;
009
010import dev.metaschema.core.util.CollectionUtil;
011import dev.metaschema.core.util.ObjectUtils;
012import dev.metaschema.oscal.lib.model.Catalog;
013import dev.metaschema.oscal.lib.model.CatalogGroup;
014import dev.metaschema.oscal.lib.model.Control;
015import dev.metaschema.oscal.lib.model.Parameter;
016import edu.umd.cs.findbugs.annotations.NonNull;
017
018public abstract class AbstractCatalogVisitor<RESULT, CONTEXT> implements ICatalogVisitor<RESULT, CONTEXT> {
019
020  /**
021   * Get a new initial/default result for the visitor.
022   *
023   * @return the result
024   */
025  protected abstract RESULT defaultResult();
026
027  /**
028   * Aggregate two results into one.
029   *
030   * @param previous
031   *          the first result
032   * @param current
033   *          the next result
034   * @return the result produced by combining the two results
035   */
036  protected RESULT aggregateResult(RESULT previous, RESULT current) {
037    return current;
038  }
039
040  @Override
041  public RESULT visitCatalog(Catalog catalog, CONTEXT context) {
042    RESULT result = CollectionUtil.listOrEmpty(catalog.getGroups()).stream()
043        .filter(Objects::nonNull)
044        .map(childGroup -> visitGroup(ObjectUtils.notNull(childGroup), context))
045        .reduce(defaultResult(), this::aggregateResult);
046    result = CollectionUtil.listOrEmpty(catalog.getControls()).stream()
047        .filter(Objects::nonNull)
048        .map(childControl -> visitControl(ObjectUtils.notNull(childControl), context))
049        .reduce(result, this::aggregateResult);
050    return CollectionUtil.listOrEmpty(catalog.getParams()).stream()
051        .filter(Objects::nonNull)
052        .map(childParameter -> visitParameter(ObjectUtils.notNull(childParameter), context))
053        .reduce(result, this::aggregateResult);
054  }
055
056  @Override
057  public RESULT visitGroup(@NonNull CatalogGroup group, CONTEXT context) {
058    RESULT result = CollectionUtil.listOrEmpty(group.getGroups()).stream()
059        .filter(Objects::nonNull)
060        .map(childGroup -> visitGroup(ObjectUtils.notNull(childGroup), context))
061        .reduce(defaultResult(), this::aggregateResult);
062    result = CollectionUtil.listOrEmpty(group.getControls()).stream()
063        .filter(Objects::nonNull)
064        .map(childControl -> visitControl(ObjectUtils.notNull(childControl), context))
065        .reduce(result, this::aggregateResult);
066    return CollectionUtil.listOrEmpty(group.getParams()).stream()
067        .filter(Objects::nonNull)
068        .map(childParameter -> visitParameter(ObjectUtils.notNull(childParameter), context))
069        .reduce(result, this::aggregateResult);
070  }
071
072  @Override
073  public RESULT visitControl(Control control, CONTEXT context) {
074    RESULT result = CollectionUtil.listOrEmpty(control.getControls()).stream()
075        .filter(Objects::nonNull)
076        .map(childControl -> visitControl(ObjectUtils.notNull(childControl), context))
077        .reduce(defaultResult(), this::aggregateResult);
078    return CollectionUtil.listOrEmpty(control.getParams()).stream()
079        .filter(Objects::nonNull)
080        .map(childParameter -> visitParameter(ObjectUtils.notNull(childParameter), context))
081        .reduce(result, this::aggregateResult);
082  }
083
084  @Override
085  public RESULT visitParameter(Parameter parameter, CONTEXT context) {
086    return defaultResult();
087  }
088
089}