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.trogdor.common;
  
  import com.fasterxml.jackson.annotation.JsonInclude;
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.DeserializationFeature;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.SerializationFeature;
  import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
  
  import java.io.File;
  
  /**
   * Utilities for working with JSON.
   */
  public class JsonUtil {
      public static final ObjectMapper JSON_SERDE;
  
      static {
          JSON_SERDE = new ObjectMapper();
          JSON_SERDE.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
          JSON_SERDE.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
          JSON_SERDE.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
          JSON_SERDE.registerModule(new Jdk8Module());
          JSON_SERDE.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
      }
  
      public static String toJsonString(Object object) {
          try {
              return JSON_SERDE.writeValueAsString(object);
          } catch (JsonProcessingException e) {
              throw new RuntimeException(e);
          }
      }
  
      public static String toPrettyJsonString(Object object) {
          try {
              return JSON_SERDE.writerWithDefaultPrettyPrinter().writeValueAsString(object);
          } catch (JsonProcessingException e) {
              throw new RuntimeException(e);
          }
      }
  
      /**
       * Determine if a string is a JSON object literal.
       * Object literals must begin with an open brace.
       *
       * @param input         The input string.
       * @return              True if the string is a JSON literal.
       */
      static boolean openBraceComesFirst(String input) {
          for (int i = 0; i < input.length(); i++) {
              char c = input.charAt(i);
              if (!Character.isWhitespace(c)) {
                  return c == '{';
              }
          }
          return false;
      }
  
      /**
       * Read a JSON object from a command-line argument.  This can take the form of a path to
       * a file containing the JSON object, or simply the raw JSON object itself.  We will assume
       * that if the string is a valid JSON object, the latter is true.  If you want to specify a
       * file name containing an open brace, you can force it to be interpreted as a file name be
       * prefixing a ./ or full path.
       *
       * @param argument      The command-line argument.
       * @param clazz         The class of the object to be read.
       * @param <T>           The object type.
       * @return              The object which we read.
       */
      public static <T> T objectFromCommandLineArgument(String argument, Class<T> clazz) throws Exception {
          if (openBraceComesFirst(argument)) {
              return JSON_SERDE.readValue(argument, clazz);
          } else {
              return JSON_SERDE.readValue(new File(argument), clazz);
          }
      }
  }
  