1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.

     2 // Use of this source code is governed by a BSD-style license that can be

     3 // found in the LICENSE file.

     4 

     5 package org.chromium.sdk.internal;

     6 

     7 import java.io.IOException;

     8 import java.io.StringWriter;

     9 import java.util.logging.Level;

    10 import java.util.logging.Logger;

    11 

    12 import org.json.simple.JSONArray;

    13 import org.json.simple.JSONObject;

    14 import org.json.simple.JSONStreamAware;

    15 import org.json.simple.parser.JSONParser;

    16 import org.json.simple.parser.ParseException;

    17 

    18 /**

    19  * A utility for JSON-related data conversion.

    20  */

    21 public class JsonUtil {

    22 

    23   private static final Logger LOGGER = Logger.getLogger(JsonUtil.class.getName());

    24 

    25   /**

    26    * Converts a JSONStreamAware into a String.

    27    *

    28    * @param object the object to convert

    29    * @return a JSON String representation of the object

    30    */

    31   public static String streamAwareToJson(JSONStreamAware object) {

    32     StringWriter out = new StringWriter();

    33     try {

    34       object.writeJSONString(out);

    35     } catch (IOException e) {

    36       return null;

    37     }

    38     return out.toString();

    39   }

    40 

    41   /**

    42    * @param json a JSON representation of an object (rather than an array or any

    43    *        other type)

    44    * @return a JSONObject represented by json, or null if json does not

    45    *         represent a valid JSONObject

    46    * @throws ParseException

    47    */

    48   public static JSONObject jsonObjectFromJson(String json) throws ParseException {

    49     JSONParser p = new JSONParser();

    50     Object parsed = p.parse(json);

    51     if (false == parsed instanceof JSONObject) {

    52       LOGGER.log(Level.SEVERE, "Not a JSON object: {0}", json);

    53       return null;

    54     }

    55     return (JSONObject) parsed;

    56   }

    57 

    58   /**

    59    * Helper function to rip out an integer number from a JSON payload.

    60    *

    61    * @param obj JSON payload

    62    * @param key to look up

    63    * @return null if key not found or bad type

    64    */

    65   public static Long getAsLong(JSONObject obj, CharSequence key) {

    66     String keyString = key.toString();

    67     Object v = obj.get(keyString);

    68     if (v instanceof Long || v == null) {

    69       return (Long) v;

    70     }

    71 

    72     LOGGER.log(Level.SEVERE, "Key: {0}, found value: {1}", new Object[] {keyString, v});

    73     return null;

    74   }

    75 

    76   /**

    77    * Helper function to rip out a double from a JSON payload.

    78    *

    79    * @param obj JSON payload

    80    * @param key to look up

    81    * @return null if key not found or bad type

    82    */

    83   public static Double getAsDouble(JSONObject obj, CharSequence key) {

    84     String keyString = key.toString();

    85     Object v = obj.get(keyString);

    86     if (v instanceof Double || v == null) {

    87       return (Double) v;

    88     }

    89     LOGGER.log(Level.SEVERE, "Key: {0}, found value: {1}", new Object[] {keyString, v});

    90     return null;

    91   }

    92 

    93   /**

    94    * Helper function to rip out a string from a JSON payload.

    95    *

    96    * @param obj JSON payload

    97    * @param key to look up

    98    * @return null if key not found or bad type

    99    */

   100   public static String getAsString(JSONObject obj, CharSequence key) {

   101     String keyString = key.toString();

   102     Object v = obj.get(keyString);

   103     if (v instanceof String || v == null) {

   104       return (String) v;

   105     }

   106     return String.valueOf(v);

   107   }

   108 

   109   /**

   110    * Helper function to rip out a Boolean from a JSON payload.

   111    *

   112    * @param obj JSON payload

   113    * @param key to look up

   114    * @return Boolean.FALSE if key not found

   115    */

   116   public static Boolean getAsBoolean(JSONObject obj, CharSequence key) {

   117     String keyString = key.toString();

   118     Object v = obj.get(keyString);

   119     if (v instanceof Boolean || v == null) {

   120       return v != null

   121           ? (Boolean) v

   122           : false;

   123     }

   124 

   125     LOGGER.log(Level.SEVERE, "Key: {0}, found value: {1}", new Object[] {keyString, v});

   126     return false;

   127   }

   128 

   129   /**

   130    * Helper function to rip out a nested JSON object from the payload.

   131    *

   132    * @param obj JSON payload

   133    * @param key to look up

   134    * @return null if key not found

   135    */

   136   public static JSONObject getAsJSON(JSONObject obj, CharSequence key) {

   137     String keyString = key.toString();

   138     Object v = obj.get(keyString);

   139     if (v instanceof JSONObject || v == null) {

   140       return (JSONObject) v;

   141     }

   142 

   143     LOGGER.log(Level.SEVERE, "Key: {0}, found value: {1}", new Object[] {keyString, v});

   144     return null;

   145   }

   146 

   147   /**

   148    * Helper function to rip out a nested JSON object from the payload or throw an exception.

   149    * @param obj JSON payload

   150    * @param key to look up

   151    * @return not null

   152    * @throws JsonException if failed to rip out the object

   153    */

   154   public static JSONObject getAsJSONStrict(JSONObject obj, CharSequence key) {

   155     JSONObject result = getAsJSON(obj, key);

   156     if (result == null) {

   157       throw new JsonException("Failed to find property '" + key);

   158     }

   159     return result;

   160   }

   161 

   162   /**

   163    * Helper function to rip out a JSONArray from the payload.

   164    *

   165    * @param obj JSON payload

   166    * @param key to look up

   167    * @return null if key not found

   168    */

   169   public static JSONArray getAsJSONArray(JSONObject obj, CharSequence key) {

   170     String keyString = key.toString();

   171     Object v = obj.get(keyString);

   172     if (v instanceof JSONArray || v == null) {

   173       return (JSONArray) v;

   174     }

   175 

   176     LOGGER.log(Level.SEVERE, "Key: {0}, found value: {1}", new Object[] {keyString, v});

   177     return null;

   178   }

   179 

   180   /**

   181    * Helper function to rip out a JSONArray from the payload or throw an exception.

   182    *

   183    * @param obj JSON payload

   184    * @param key to look up

   185    * @return not null

   186    * @throws JsonException if failed to rip out the array

   187    */

   188   public static JSONArray getAsJSONArrayStrict(JSONObject obj, CharSequence key) {

   189     JSONArray result = getAsJSONArray(obj, key);

   190     if (result == null) {

   191       throw new JsonException("Failed to find property '" + key + "' of array type");

   192     }

   193     return result;

   194   }

   195 

   196   /**

   197    * @param value to check

   198    * @return whether the value can be parsed as an integer

   199    */

   200   public static boolean isInteger(String value) {

   201     try {

   202       Integer.parseInt(value);

   203       return true;

   204     } catch (NumberFormatException e) {

   205       return false;

   206     }

   207   }

   208 

   209   public static String quoteString(String string) {

   210     return "\"" + string + "\"";

   211   }

   212 

   213   private JsonUtil() {

   214     // not instantiable

   215   }

   216 }