code: /*
   * citygml-tools - Collection of tools for processing CityGML files
   * https://github.com/citygml4j/citygml-tools
   *
   * citygml-tools is part of the citygml4j project
   *
   * Copyright 2018-2023 Claus Nagel <claus.nagel@gmail.com>
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.citygml4j.tools.util;
  
  import org.citygml4j.core.model.appearance.AbstractSurfaceDataProperty;
  import org.citygml4j.core.model.appearance.AbstractTexture;
  import org.citygml4j.core.model.appearance.Appearance;
  import org.citygml4j.core.model.appearance.X3DMaterial;
  import org.citygml4j.core.model.core.AbstractFeature;
  import org.citygml4j.core.visitor.ObjectWalker;
  import org.xmlobjects.gml.model.GMLObject;
  import org.xmlobjects.model.Child;
  
  import java.util.*;
  
  public class AppearanceFilter {
      public static final String NULL_THEME = "null";
      private final AppearanceProcessor appearanceProcessor = new AppearanceProcessor();
      private final Map<String, Integer> counter = new TreeMap<>();
  
      private Set<String> themes;
      private boolean onlyTextures;
      private boolean onlyMaterials;
      private boolean keep;
  
      private AppearanceFilter() {
      }
  
      public static AppearanceFilter newInstance() {
          return new AppearanceFilter();
      }
  
      public AppearanceFilter withThemes(Set<String> themes) {
          this.themes = themes;
          return this;
      }
  
      public AppearanceFilter onlyTextures(boolean onlyTextures) {
          this.onlyTextures = onlyTextures;
          return this;
      }
  
      public AppearanceFilter onlyMaterials(boolean onlyMaterials) {
          this.onlyMaterials = onlyMaterials;
          return this;
      }
  
      public boolean filter(AbstractFeature feature) {
          keep = true;
          feature.accept(appearanceProcessor);
          return !(feature instanceof Appearance) || keep;
      }
  
      public Map<String, Integer> getCounter() {
          return counter;
      }
  
      public void reset() {
          counter.clear();
      }
  
      private class AppearanceProcessor extends ObjectWalker {
  
          @Override
          public void visit(Appearance appearance) {
              if (shouldRemove(appearance)) {
                  Child property = appearance.getParent();
                  if (property == null) {
                      keep = false;
                  } else {
                      Child parent = property.getParent();
                      if (parent instanceof GMLObject) {
                          ((GMLObject) parent).unsetProperty(property, true);
                      }
                  }
              }
          }
  
          private boolean shouldRemove(Appearance appearance) {
              if (themes == null
                      || (appearance.getTheme() == null && themes.contains(NULL_THEME))
                      || themes.contains(appearance.getTheme())) {
                  if (!onlyTextures && !onlyMaterials) {
                      count(appearance, counter);
                      return true;
                  }
  
                  Class<?> target = onlyMaterials ? X3DMaterial.class : AbstractTexture.class;
                  List<AbstractSurfaceDataProperty> deleteList = new ArrayList<>();
                  appearance.getSurfaceData().stream()
                          .filter(property -> target.isInstance(property.getObject()))
                          .forEach(property -> {
                              count(property.getObject(), counter);
                              deleteList.add(property);
                          });
  
                  appearance.getSurfaceData().removeAll(deleteList);
                  if (!appearance.isSetSurfaceData()) {
                      count(appearance, counter);
                      return true;
                  }
              }
  
              return false;
          }
  
          private void count(Object object, Map<String, Integer> counter) {
              counter.merge(object.getClass().getSimpleName(), 1, Integer::sum);
          }
      }
  }
  