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The hassle-free way to add analytics to your Android app.
There is a newer version: 3.4.0
/*
 * Copyright 2015 Prateek Srivastava
 *
 * 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 com.segment.analytics;

import android.util.JsonReader;
import android.util.JsonToken;
import android.util.JsonWriter;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * Cartographer creates {@link Map} from JSON encoded streams and encodes Maps to their JSON
 * representation.
 */
class Cartographer {

  static final Cartographer INSTANCE = new Cartographer();

  private Cartographer() {
  }

  /**
   * Deserializes the specified json into a {@link Map}. If you have the Json in a {@link Reader}
   * form instead of a {@link String}, use {@link #fromJson(Reader)} instead.
   */
  Map fromJson(String json) throws IOException {
    return fromJson(new StringReader(json));
  }

  /**
   * Deserializes the json read from the specified {@link Reader} into a {@link Map}. If you have
   * the Json in a String form instead of a {@link Reader}, use {@link #fromJson(String)} instead.
   */
  Map fromJson(Reader reader) throws IOException {
    JsonReader jsonReader = new JsonReader(reader);
    try {
      return readerToMap(jsonReader);
    } finally {
      reader.close();
    }
  }

  /**
   * Serializes the map into it's json representation and returns it as a String. If you want to
   * write the json to {@link Writer} instead of retrieving it as a String, use {@link #toJson(Map,
   * Writer)} instead.
   */
  String toJson(Map map) throws IOException {
    StringWriter stringWriter = new StringWriter();
    toJson(map, stringWriter);
    return stringWriter.toString();
  }

  /**
   * Serializes the map into it's json representation into the provided {@link Writer}. If you want
   * to retrieve the json as a string, use {@link #toJson(Map)} instead.
   */
  void toJson(Map map, Writer writer) throws IOException {
    if (map == null) {
      throw new IllegalArgumentException("map == null");
    }

    JsonWriter jsonWriter = new JsonWriter(writer);
    try {
      mapToWriter(map, jsonWriter);
    } finally {
      jsonWriter.close();
    }
  }

  // Decoding

  /** Reads the {@link JsonReader} into a {@link Map}. */
  private Map readerToMap(JsonReader reader) throws IOException {
    Map map = new LinkedHashMap<>();
    reader.beginObject();
    while (reader.hasNext()) {
      map.put(reader.nextName(), readValue(reader));
    }
    reader.endObject();
    return map;
  }

  /** Reads the {@link JsonReader} into a {@link List}. */
  private List