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.bifromq.apiserver.http.handler.utils;
  
  import com.fasterxml.jackson.core.JsonGenerator;
  import com.fasterxml.jackson.databind.JsonNode;
  import com.fasterxml.jackson.databind.JsonSerializer;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.SerializerProvider;
  import com.fasterxml.jackson.databind.module.SimpleModule;
  import com.google.protobuf.util.JsonFormat;
  import java.io.IOException;
  import org.apache.bifromq.basekv.proto.BalancerStateSnapshot;
  
  public class JSONUtils {
      public static final ObjectMapper MAPPER;
  
      static {
          MAPPER = new ObjectMapper();
          SimpleModule module = new SimpleModule();
          module.addSerializer(BalancerStateSnapshot.class, new BalancerStateSnapshotJsonSerializer());
          MAPPER.registerModule(module);
      }
  
      private static class BalancerStateSnapshotJsonSerializer extends JsonSerializer<BalancerStateSnapshot> {
          private static final JsonFormat.Printer PRINTER = JsonFormat.printer()
              .alwaysPrintFieldsWithNoPresence()
              .preservingProtoFieldNames();
  
          @Override
          public void serialize(BalancerStateSnapshot value, JsonGenerator gen, SerializerProvider serializers)
              throws IOException {
              String json = PRINTER.print(value);
              JsonNode jsonNode = new ObjectMapper().readTree(json);
              gen.writeObject(jsonNode);
          }
      }
  }
  