org.richfaces.json

## Class JSONObject

- java.lang.Object
- - org.richfaces.json.JSONObject

- All Implemented Interfaces:
    Serializable

      public class JSONObject
      extends Object
      implements Serializable

  A JSONObject is an unordered collection of name/value pairs. Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names. The internal form is an object having `get` and `opt` methods for accessing the values by name, and `put` methods for adding or replacing values by name. The values can be any of these types: `Boolean`, `JSONArray`, `JSONObject`, `Number`, `String`, or the `JSONObject.NULL` object. A JSONObject constructor can be used to convert an external form JSON text into an internal form whose values can be retrieved with the `get` and `opt` methods, or to convert values into a JSON text using the `put` and `toString` methods. A `get` method returns a value if one can be found, and throws an exception if one cannot be found. An `opt` method returns a default value instead of throwing an exception, and so is useful for obtaining optional values.

  The generic `get()` and `opt()` methods return an object, which you can cast or query for type. There are also typed `get` and `opt` methods that do type checking and type coersion for you.

  The `put` methods adds values to an object. For example,

       myString = new JSONObject().put("JSON", "Hello, World!").toString();

  produces the string `{"JSON": "Hello, World"}`.

  The texts produced by the `toString` methods strictly conform to the JSON sysntax rules. The constructors are more forgiving in the texts they will accept:
  - An extra `,` (comma) may appear just before the closing brace.
  - Strings may be quoted with `'` (single quote).
  - Strings do not need to be quoted at all if they do not begin with a quote or single quote, and if they do not contain leading or trailing spaces, and if they do not contain any of these characters: `{ } [ ] / \ : , = ; #` and if they do not look like numbers and if they are not the reserved words `true`, `false`, or `null`.
  - Keys can be followed by `=` or `=>` as well as by `:`.
  - Values can be followed by `;` (semicolon) as well as by `,` (comma).
  - Numbers may have the `0-` (octal) or `0x-` (hex) prefix.
  - Comments written in the slashshlash, slashstar, and hash conventions will be ignored.
  Version:
    2
  Author:
    JSON.org
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static Object` | `NULL` It is sometimes more convenient and less ambiguous to have a `NULL` object than to use Java's `null` value.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `JSONObject()` Construct an empty JSONObject.
    `JSONObject(JSONObject jo, String[] sa)` Construct a JSONObject from a subset of another JSONObject.
    `JSONObject(JSONTokener x)` Construct a JSONObject from a JSONTokener.
    `JSONObject(Map map)` Construct a JSONObject from a Map.
    `JSONObject(Object object, String[] names)` Construct a JSONObject from an Object, using reflection to find the public members.
    `JSONObject(String string)` Construct a JSONObject from a string.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `JSONObject` | `accumulate(String key, Object value)` Accumulate values under a key.
    `JSONObject` | `append(String key, Object value)` Append values to the array under a key.
    `static String` | `doubleToString(double d)` Produce a string from a double.
    `Object` | `get(String key)` Get the value object associated with a key.
    `boolean` | `getBoolean(String key)` Get the boolean value associated with a key.
    `double` | `getDouble(String key)` Get the double value associated with a key.
    `int` | `getInt(String key)` Get the int value associated with a key.
    `JSONArray` | `getJSONArray(String key)` Get the JSONArray value associated with a key.
    `JSONObject` | `getJSONObject(String key)` Get the JSONObject value associated with a key.
    `long` | `getLong(String key)` Get the long value associated with a key.
    `String` | `getString(String key)` Get the string associated with a key.
    `boolean` | `has(String key)` Determine if the JSONObject contains a specific key.
    `boolean` | `isNull(String key)` Determine if the value associated with the key is null or if there is no value.
    `Iterator` | `keys()` Get an enumeration of the keys of the JSONObject.
    `int` | `length()` Get the number of keys stored in the JSONObject.
    `JSONArray` | `names()` Produce a JSONArray containing the names of the elements of this JSONObject.
    `static String` | `numberToString(Number n)` Produce a string from a Number.
    `Object` | `opt(String key)` Get an optional value associated with a key.
    `boolean` | `optBoolean(String key)` Get an optional boolean associated with a key.
    `boolean` | `optBoolean(String key, boolean defaultValue)` Get an optional boolean associated with a key.
    `double` | `optDouble(String key)` Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number.
    `double` | `optDouble(String key, double defaultValue)` Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number.
    `int` | `optInt(String key)` Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number.
    `int` | `optInt(String key, int defaultValue)` Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number.
    `JSONArray` | `optJSONArray(String key)` Get an optional JSONArray associated with a key.
    `JSONObject` | `optJSONObject(String key)` Get an optional JSONObject associated with a key.
    `long` | `optLong(String key)` Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number.
    `long` | `optLong(String key, long defaultValue)` Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number.
    `String` | `optString(String key)` Get an optional string associated with a key.
    `String` | `optString(String key, String defaultValue)` Get an optional string associated with a key.
    `JSONObject` | `put(String key, boolean value)` Put a key/boolean pair in the JSONObject.
    `JSONObject` | `put(String key, Collection value)` Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.
    `JSONObject` | `put(String key, double value)` Put a key/double pair in the JSONObject.
    `JSONObject` | `put(String key, int value)` Put a key/int pair in the JSONObject.
    `JSONObject` | `put(String key, long value)` Put a key/long pair in the JSONObject.
    `JSONObject` | `put(String key, Map value)` Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.
    `JSONObject` | `put(String key, Object value)` Put a key/value pair in the JSONObject.
    `JSONObject` | `putOpt(String key, Object value)` Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.
    `static String` | `quote(String string)` Produce a string in double quotes with backslash sequences in all the right places.
    `Object` | `remove(String key)` Remove a name and its value, if present.
    `JSONArray` | `toJSONArray(JSONArray names)` Produce a JSONArray containing the values of the members of this JSONObject.
    `String` | `toString()` Make a JSON text of this JSONObject.
    `String` | `toString(int indentFactor)` Make a prettyprinted JSON text of this JSONObject.
    `Writer` | `write(Writer writer)` Write the contents of the JSONObject as JSON text to a writer.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### NULL

          public static final Object NULL

      It is sometimes more convenient and less ambiguous to have a `NULL` object than to use Java's `null` value. `JSONObject.NULL.equals(null)` returns `true`. `JSONObject.NULL.toString()` returns `"null"`.

  - ### Constructor Detail

    - #### JSONObject

          public JSONObject()

      Construct an empty JSONObject.

    - #### JSONObject

          public JSONObject(JSONTokener x)
                     throws JSONException

      Construct a JSONObject from a JSONTokener.
      Parameters:
        `x` - A JSONTokener object containing the source string.
      Throws:
        `JSONException` - If there is a syntax error in the source string.

    - #### JSONObject

          public JSONObject(Map map)

      Construct a JSONObject from a Map.
      Parameters:
        `map` - A map object that can be used to initialize the contents of the JSONObject.

    - #### JSONObject

          public JSONObject(String string)
                     throws JSONException

      Construct a JSONObject from a string. This is the most commonly used JSONObject constructor.
      Parameters:
        `string` - A string beginning with `{` (left brace) and ending with `}` (right brace).
      Throws:
        `JSONException` - If there is a syntax error in the source string.

    - #### JSONObject

          public JSONObject(JSONObject jo,
                            String[] sa)
                     throws JSONException

      Construct a JSONObject from a subset of another JSONObject. An array of strings is used to identify the keys that should be copied. Missing keys are ignored.
      Parameters:
        `jo` - A JSONObject.
        `sa` - An array of strings.
      Throws:
        `JSONException` - If a value is a non-finite number.

    - #### JSONObject

          public JSONObject(Object object,
                            String[] names)

      Construct a JSONObject from an Object, using reflection to find the public members. The resulting JSONObject's keys will be the strings from the names array, and the values will be the field values associated with those keys in the object. If a key is not found or not visible, then it will not be copied into the new JSONObject.
      Parameters:
        `object` - An object that has fields that should be used to make a JSONObject.
        `names` - An array of strings, the names of the fields to be used from the object.

  - ### Method Detail

    - #### accumulate

          public JSONObject accumulate(String key,
                                       Object value)
                                throws JSONException

      Accumulate values under a key. It is similar to the put method except that if there is already an object stored under the key then a JSONArray is stored under the key to hold all of the accumulated values. If there is already a JSONArray, then the new value is appended to it. In contrast, the put method replaces the previous value.
      Parameters:
        `key` - A key string.
        `value` - An object to be accumulated under the key.
      Returns:
        this.
      Throws:
        `JSONException` - If the value is an invalid number or if the key is null.

    - #### append

          public JSONObject append(String key,
                                   Object value)
                            throws JSONException

      Append values to the array under a key. If the key does not exist in the JSONObject, then the key is put in the JSONObject with its value being a JSONArray containing the value parameter. If the key was already associated with a JSONArray, then the value parameter is appended to it.
      Parameters:
        `key` - A key string.
        `value` - An object to be accumulated under the key.
      Returns:
        this.
      Throws:
        `JSONException` - If the key is null or if the current value associated with the key is not a JSONArray.

    - #### doubleToString

          public static String doubleToString(double d)

      Produce a string from a double. The string "null" will be returned if the number is not finite.
      Parameters:
        `d` - A double.
      Returns:
        A String.

    - #### get

          public Object get(String key)
                     throws JSONException

      Get the value object associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        The object associated with the key.
      Throws:
        `JSONException` - if the key is not found.

    - #### getBoolean

          public boolean getBoolean(String key)
                             throws JSONException

      Get the boolean value associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        The truth.
      Throws:
        `JSONException` - if the value is not a Boolean or the String "true" or "false".

    - #### getDouble

          public double getDouble(String key)
                           throws JSONException

      Get the double value associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        The numeric value.
      Throws:
        `JSONException` - if the key is not found or if the value is not a Number object and cannot be converted to a number.

    - #### getInt

          public int getInt(String key)
                     throws JSONException

      Get the int value associated with a key. If the number value is too large for an int, it will be clipped.
      Parameters:
        `key` - A key string.
      Returns:
        The integer value.
      Throws:
        `JSONException` - if the key is not found or if the value cannot be converted to an integer.

    - #### getJSONArray

          public JSONArray getJSONArray(String key)
                                 throws JSONException

      Get the JSONArray value associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        A JSONArray which is the value.
      Throws:
        `JSONException` - if the key is not found or if the value is not a JSONArray.

    - #### getJSONObject

          public JSONObject getJSONObject(String key)
                                   throws JSONException

      Get the JSONObject value associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        A JSONObject which is the value.
      Throws:
        `JSONException` - if the key is not found or if the value is not a JSONObject.

    - #### getLong

          public long getLong(String key)
                       throws JSONException

      Get the long value associated with a key. If the number value is too long for a long, it will be clipped.
      Parameters:
        `key` - A key string.
      Returns:
        The long value.
      Throws:
        `JSONException` - if the key is not found or if the value cannot be converted to a long.

    - #### getString

          public String getString(String key)
                           throws JSONException

      Get the string associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        A string which is the value.
      Throws:
        `JSONException` - if the key is not found.

    - #### has

          public boolean has(String key)

      Determine if the JSONObject contains a specific key.
      Parameters:
        `key` - A key string.
      Returns:
        true if the key exists in the JSONObject.

    - #### isNull

          public boolean isNull(String key)

      Determine if the value associated with the key is null or if there is no value.
      Parameters:
        `key` - A key string.
      Returns:
        true if there is no value associated with the key or if the value is the JSONObject.NULL object.

    - #### keys

          public Iterator keys()

      Get an enumeration of the keys of the JSONObject.
      Returns:
        An iterator of the keys.

    - #### length

          public int length()

      Get the number of keys stored in the JSONObject.
      Returns:
        The number of keys in the JSONObject.

    - #### names

          public JSONArray names()

      Produce a JSONArray containing the names of the elements of this JSONObject.
      Returns:
        A JSONArray containing the key strings, or null if the JSONObject is empty.

    - #### numberToString

          public static String numberToString(Number n)
                                       throws JSONException

      Produce a string from a Number.
      Parameters:
        `n` - A Number
      Returns:
        A String.
      Throws:
        `JSONException` - If n is a non-finite number.

    - #### opt

          public Object opt(String key)

      Get an optional value associated with a key.
      Parameters:
        `key` - A key string.
      Returns:
        An object which is the value, or null if there is no value.

    - #### optBoolean

          public boolean optBoolean(String key)

      Get an optional boolean associated with a key. It returns false if there is no such key, or if the value is not Boolean.TRUE or the String "true".
      Parameters:
        `key` - A key string.
      Returns:
        The truth.

    - #### optBoolean

          public boolean optBoolean(String key,
                                    boolean defaultValue)

      Get an optional boolean associated with a key. It returns the defaultValue if there is no such key, or if it is not a Boolean or the String "true" or "false" (case insensitive).
      Parameters:
        `key` - A key string.
        `defaultValue` - The default.
      Returns:
        The truth.

    - #### put

          public JSONObject put(String key,
                                Collection value)
                         throws JSONException

      Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.
      Parameters:
        `key` - A key string.
        `value` - A Collection value.
      Returns:
        this.
      Throws:
        `JSONException`

    - #### optDouble

          public double optDouble(String key)

      Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
        `key` - A string which is the key.
      Returns:
        An object which is the value.

    - #### optDouble

          public double optDouble(String key,
                                  double defaultValue)

      Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
        `key` - A key string.
        `defaultValue` - The default.
      Returns:
        An object which is the value.

    - #### optInt

          public int optInt(String key)

      Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
        `key` - A key string.
      Returns:
        An object which is the value.

    - #### optInt

          public int optInt(String key,
                            int defaultValue)

      Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
        `key` - A key string.
        `defaultValue` - The default.
      Returns:
        An object which is the value.

    - #### optJSONArray

          public JSONArray optJSONArray(String key)

      Get an optional JSONArray associated with a key. It returns null if there is no such key, or if its value is not a JSONArray.
      Parameters:
        `key` - A key string.
      Returns:
        A JSONArray which is the value.

    - #### optJSONObject

          public JSONObject optJSONObject(String key)

      Get an optional JSONObject associated with a key. It returns null if there is no such key, or if its value is not a JSONObject.
      Parameters:
        `key` - A key string.
      Returns:
        A JSONObject which is the value.

    - #### optLong

          public long optLong(String key)

      Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
        `key` - A key string.
      Returns:
        An object which is the value.

    - #### optLong

          public long optLong(String key,
                              long defaultValue)

      Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
        `key` - A key string.
        `defaultValue` - The default.
      Returns:
        An object which is the value.

    - #### optString

          public String optString(String key)

      Get an optional string associated with a key. It returns an empty string if there is no such key. If the value is not a string and is not null, then it is coverted to a string.
      Parameters:
        `key` - A key string.
      Returns:
        A string which is the value.

    - #### optString

          public String optString(String key,
                                  String defaultValue)

      Get an optional string associated with a key. It returns the defaultValue if there is no such key.
      Parameters:
        `key` - A key string.
        `defaultValue` - The default.
      Returns:
        A string which is the value.

    - #### put

          public JSONObject put(String key,
                                boolean value)
                         throws JSONException

      Put a key/boolean pair in the JSONObject.
      Parameters:
        `key` - A key string.
        `value` - A boolean which is the value.
      Returns:
        this.
      Throws:
        `JSONException` - If the key is null.

    - #### put

          public JSONObject put(String key,
                                double value)
                         throws JSONException

      Put a key/double pair in the JSONObject.
      Parameters:
        `key` - A key string.
        `value` - A double which is the value.
      Returns:
        this.
      Throws:
        `JSONException` - If the key is null or if the number is invalid.

    - #### put

          public JSONObject put(String key,
                                int value)
                         throws JSONException

      Put a key/int pair in the JSONObject.
      Parameters:
        `key` - A key string.
        `value` - An int which is the value.
      Returns:
        this.
      Throws:
        `JSONException` - If the key is null.

    - #### put

          public JSONObject put(String key,
                                long value)
                         throws JSONException

      Put a key/long pair in the JSONObject.
      Parameters:
        `key` - A key string.
        `value` - A long which is the value.
      Returns:
        this.
      Throws:
        `JSONException` - If the key is null.

    - #### put

          public JSONObject put(String key,
                                Map value)
                         throws JSONException

      Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.
      Parameters:
        `key` - A key string.
        `value` - A Map value.
      Returns:
        this.
      Throws:
        `JSONException`

    - #### put

          public JSONObject put(String key,
                                Object value)
                         throws JSONException

      Put a key/value pair in the JSONObject. If the value is null, then the key will be removed from the JSONObject if it is present.
      Parameters:
        `key` - A key string.
        `value` - An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
      Returns:
        this.
      Throws:
        `JSONException` - If the value is non-finite number or if the key is null.

    - #### putOpt

          public JSONObject putOpt(String key,
                                   Object value)
                            throws JSONException

      Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.
      Parameters:
        `key` - A key string.
        `value` - An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
      Returns:
        this.
      Throws:
        `JSONException` - If the value is a non-finite number.

    - #### quote

          public static String quote(String string)

      Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within
      Parameters:
        `string` - A String
      Returns:
        A String correctly formatted for insertion in a JSON text.

    - #### remove

          public Object remove(String key)

      Remove a name and its value, if present.
      Parameters:
        `key` - The name to be removed.
      Returns:
        The value that was associated with the name, or null if there was no value.

    - #### toJSONArray

          public JSONArray toJSONArray(JSONArray names)
                                throws JSONException

      Produce a JSONArray containing the values of the members of this JSONObject.
      Parameters:
        `names` - A JSONArray containing a list of key strings. This determines the sequence of the values in the result.
      Returns:
        A JSONArray of values.
      Throws:
        `JSONException` - If any of the values are non-finite numbers.

    - #### toString

          public String toString()

      Make a JSON text of this JSONObject. For compactness, no whitespace is added. If this would not result in a syntactically correct JSON text, then null will be returned instead.

      Warning: This method assumes that the data structure is acyclical.
      Overrides:
        `toString` in class `Object`
      Returns:
        a printable, displayable, portable, transmittable representation of the object, beginning with `{` (left brace) and ending with `}` (right brace).

    - #### toString

          public String toString(int indentFactor)
                          throws JSONException

      Make a prettyprinted JSON text of this JSONObject.

      Warning: This method assumes that the data structure is acyclical.
      Parameters:
        `indentFactor` - The number of spaces to add to each level of indentation.
      Returns:
        a printable, displayable, portable, transmittable representation of the object, beginning with `{` (left brace) and ending with `}` (right brace).
      Throws:
        `JSONException` - If the object contains an invalid number.

    - #### write

          public Writer write(Writer writer)
                       throws JSONException

      Write the contents of the JSONObject as JSON text to a writer. For compactness, no whitespace is added.

      Warning: This method assumes that the data structure is acyclical.
      Returns:
        The writer.
      Throws:
        `JSONException`

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