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.kafka.server.util.json;
  
  import com.fasterxml.jackson.databind.JsonMappingException;
  import com.fasterxml.jackson.databind.JsonNode;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  
  public interface DecodeJson<T> {
      /**
       * Decode the JSON node provided into an instance of `T`.
       *
       * @throws JsonMappingException if `node` cannot be decoded into `T`.
       */
      T decode(JsonNode node) throws JsonMappingException;
  
      static JsonMappingException throwJsonMappingException(String expectedType, JsonNode node) {
          return new JsonMappingException(null, String.format("Expected `%s` value, received %s", expectedType, node));
      }
  
      final class DecodeBoolean implements DecodeJson<Boolean> {
          @Override
          public Boolean decode(JsonNode node) throws JsonMappingException {
              if (node.isBoolean()) {
                  return node.booleanValue();
              }
              throw throwJsonMappingException(Boolean.class.getSimpleName(), node);
          }
      }
  
      final class DecodeDouble implements DecodeJson<Double> {
          @Override
          public Double decode(JsonNode node) throws JsonMappingException {
              if (node.isDouble() || node.isLong() || node.isInt()) {
                  return node.doubleValue();
              }
              throw throwJsonMappingException(Double.class.getSimpleName(), node);
          }
      }
  
      final class DecodeInteger implements DecodeJson<Integer> {
          @Override
          public Integer decode(JsonNode node) throws JsonMappingException {
              if (node.isInt()) {
                  return node.intValue();
              }
              throw throwJsonMappingException(Integer.class.getSimpleName(), node);
          }
      }
  
      final class DecodeLong implements DecodeJson<Long> {
          @Override
          public Long decode(JsonNode node) throws JsonMappingException {
              if (node.isLong() || node.isInt()) {
                  return node.longValue();
              }
              throw throwJsonMappingException(Long.class.getSimpleName(), node);
          }
      }
  
      final class DecodeString implements DecodeJson<String> {
          @Override
          public String decode(JsonNode node) throws JsonMappingException {
              if (node.isTextual()) {
                  return node.textValue();
              }
              throw throwJsonMappingException(String.class.getSimpleName(), node);
          }
      }
  
      static <E> DecodeJson<Optional<E>> decodeOptional(DecodeJson<E> decodeJson) {
          return node -> {
              if (node.isNull()) return Optional.empty();
              return Optional.of(decodeJson.decode(node));
          };
      }
  
      static <E> DecodeJson<List<E>> decodeList(DecodeJson<E> decodeJson) {
          return node -> {
              if (node.isArray()) {
                  List<E> result = new ArrayList<>();
                  Iterator<JsonNode> elements = node.elements();
                  while (elements.hasNext()) {
                      result.add(decodeJson.decode(elements.next()));
                  }
                  return result;
              }
              throw throwJsonMappingException("JSON array", node);
          };
      }
  
      static <V> DecodeJson<Map<String, V>> decodeMap(DecodeJson<V> decodeJson) {
          return node -> {
              if (node.isObject()) {
                  Map<String, V> result = new HashMap<>();
                  for (Map.Entry<String, JsonNode> entry : node.properties()) {
                      result.put(entry.getKey(), decodeJson.decode(entry.getValue()));
                  }
                  return result;
              }
              throw throwJsonMappingException("JSON object", node);
          };
      }
  }
  