content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.apache.cassandra.config;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import com.fasterxml.jackson.annotation.JsonIgnore;
  import org.yaml.snakeyaml.error.YAMLException;
  import org.yaml.snakeyaml.introspector.BeanAccess;
  import org.yaml.snakeyaml.introspector.Property;
  import org.yaml.snakeyaml.introspector.PropertyUtils;
  
  import static org.apache.cassandra.utils.FBUtilities.camelToSnake;
  
  public final class SnakeYamlLoader implements Loader
  {
      private final Helper helper = new Helper();
  
      @Override
      public Map<String, Property> getProperties(Class<?> root)
      {
          return helper.getPropertiesMap(root, BeanAccess.DEFAULT);
      }
  
      private static class Helper extends PropertyUtils
      {
          @Override
          public Map<String, Property> getPropertiesMap(Class<?> type, BeanAccess bAccess)
          {
              Map<String, Property> map;
              try
              {
                  map = super.getPropertiesMap(type, bAccess);
              }
              catch (YAMLException e)
              {
                  // some classes take a string in constructor and output as toString, these should be treated like
                  // primitive types
                  if (e.getMessage() != null && e.getMessage().startsWith("No JavaBean properties found"))
                      return Collections.emptyMap();
                  throw e;
              }
              // filter out ignores
              Set<String> ignore = new HashSet<>();
              Map<String, String> rename = new HashMap<>();
              map.values().forEach(p -> {
                  if (shouldIgnore(p))
                  {
                      ignore.add(p.getName());
                      return;
                  }
                  String snake = camelToSnake(p.getName());
                  if (!p.getName().equals(snake))
                  {
                      if (map.containsKey(snake))
                          ignore.add(p.getName());
                      else
                          rename.put(p.getName(), snake);
                  }
              });
              ignore.forEach(map::remove);
              rename.forEach((previous, desired) -> map.put(desired, map.remove(previous)));
              return map;
          }
  
          private static boolean shouldIgnore(Property p)
          {
              return !p.isWritable() || p.getAnnotation(JsonIgnore.class) != null;
          }
      }
  }
  