org.json.JSONObject Class Reference

List of all members.

Public Member Functions

 JSONObject ()
 JSONObject (JSONObject jo, String[] names)
 JSONObject (JSONTokener x) throws JSONException
 JSONObject (Map map)
 JSONObject (Object bean)
 JSONObject (Object object, String names[])
 JSONObject (String source) throws JSONException
JSONObject accumulate (String key, Object value) throws JSONException
JSONObject append (String key, Object value) throws JSONException
Object get (String key) throws JSONException
boolean getBoolean (String key) throws JSONException
double getDouble (String key) throws JSONException
int getInt (String key) throws JSONException
JSONArray getJSONArray (String key) throws JSONException
JSONObject getJSONObject (String key) throws JSONException
long getLong (String key) throws JSONException
String getString (String key) throws JSONException
boolean has (String key)
JSONObject increment (String key) throws JSONException
boolean isNull (String key)
Iterator keys ()
int length ()
JSONArray names ()
Object opt (String key)
boolean optBoolean (String key)
boolean optBoolean (String key, boolean defaultValue)
double optDouble (String key)
double optDouble (String key, double defaultValue)
int optInt (String key)
int optInt (String key, int defaultValue)
JSONArray optJSONArray (String key)
JSONObject optJSONObject (String key)
long optLong (String key)
long optLong (String key, long defaultValue)
String optString (String key)
String optString (String key, String defaultValue)
JSONObject put (String key, boolean value) throws JSONException
JSONObject put (String key, Collection value) throws JSONException
JSONObject put (String key, double value) throws JSONException
JSONObject put (String key, int value) throws JSONException
JSONObject put (String key, long value) throws JSONException
JSONObject put (String key, Map value) throws JSONException
JSONObject put (String key, Object value) throws JSONException
JSONObject putOnce (String key, Object value) throws JSONException
JSONObject putOpt (String key, Object value) throws JSONException
Object remove (String key)
Iterator sortedKeys ()
JSONArray toJSONArray (JSONArray names) throws JSONException
String toString ()
String toString (int indentFactor) throws JSONException
Writer write (Writer writer) throws JSONException

Static Public Member Functions

static String doubleToString (double d)
static String[] getNames (JSONObject jo)
static String[] getNames (Object object)
static String numberToString (Number n) throws JSONException
static String quote (String string)
static Object stringToValue (String s)

Static Public Attributes

static final Object NULL = new Null()

Package Functions

String toString (int indentFactor, int indent) throws JSONException

Static Package Functions

static void testValidity (Object o) throws JSONException
static String valueToString (Object value) throws JSONException
static String valueToString (Object value, int indentFactor, int indent) throws JSONException
static Object wrap (Object object)

Detailed Description

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 coercion 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 syntax rules. The constructors are more forgiving in the texts they will accept:

Author:
JSON.org
Version:
2010-05-17

Constructor & Destructor Documentation

org.json.JSONObject.JSONObject (  ) 

Construct an empty JSONObject.

org.json.JSONObject.JSONObject ( JSONObject  jo,
String[]  names 
)

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.
names An array of strings.
Exceptions:
JSONException 
JSONException If a value is a non-finite number or if a name is duplicated.
org.json.JSONObject.JSONObject ( JSONTokener  x  )  throws JSONException

Construct a JSONObject from a JSONTokener.

Parameters:
x A JSONTokener object containing the source string.
Exceptions:
JSONException If there is a syntax error in the source string or a duplicated key.
org.json.JSONObject.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.
Exceptions:
JSONException 
org.json.JSONObject.JSONObject ( Object  bean  ) 

Construct a JSONObject from an Object using bean getters. It reflects on all of the public methods of the object. For each of the methods with no parameters and a name starting with "get" or "is" followed by an uppercase letter, the method is invoked, and a key and the value returned from the getter method are put into the new JSONObject.

The key is formed by removing the "get" or "is" prefix. If the second remaining character is not upper case, then the first character is converted to lower case.

For example, if an object has a method named "getName", and if the result of calling object.getName() is "Larry Fine", then the JSONObject will contain "name": "Larry Fine".

Parameters:
bean An object that has getter methods that should be used to make a JSONObject.
org.json.JSONObject.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 obtained from the object.
org.json.JSONObject.JSONObject ( String  source  )  throws JSONException

Construct a JSONObject from a source JSON text string. This is the most commonly used JSONObject constructor.

Parameters:
source A string beginning with { (left brace) and ending with } (right brace).
Exceptions:
JSONException If there is a syntax error in the source string or a duplicated key.

Member Function Documentation

JSONObject org.json.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.
Exceptions:
JSONException If the value is an invalid number or if the key is null.
JSONObject org.json.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.
Exceptions:
JSONException If the key is null or if the current value associated with the key is not a JSONArray.
static String org.json.JSONObject.doubleToString ( double  d  )  [static]

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.
Object org.json.JSONObject.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.
Exceptions:
JSONException if the key is not found.
boolean org.json.JSONObject.getBoolean ( String  key  )  throws JSONException

Get the boolean value associated with a key.

Parameters:
key A key string.
Returns:
The truth.
Exceptions:
JSONException if the value is not a Boolean or the String "true" or "false".
double org.json.JSONObject.getDouble ( String  key  )  throws JSONException

Get the double value associated with a key.

Parameters:
key A key string.
Returns:
The numeric value.
Exceptions:
JSONException if the key is not found or if the value is not a Number object and cannot be converted to a number.
int org.json.JSONObject.getInt ( String  key  )  throws JSONException

Get the int value associated with a key.

Parameters:
key A key string.
Returns:
The integer value.
Exceptions:
JSONException if the key is not found or if the value cannot be converted to an integer.
JSONArray org.json.JSONObject.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.
Exceptions:
JSONException if the key is not found or if the value is not a JSONArray.
JSONObject org.json.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.
Exceptions:
JSONException if the key is not found or if the value is not a JSONObject.
long org.json.JSONObject.getLong ( String  key  )  throws JSONException

Get the long value associated with a key.

Parameters:
key A key string.
Returns:
The long value.
Exceptions:
JSONException if the key is not found or if the value cannot be converted to a long.
static String [] org.json.JSONObject.getNames ( Object  object  )  [static]

Get an array of field names from an Object.

Returns:
An array of field names, or null if there are no names.
static String [] org.json.JSONObject.getNames ( JSONObject  jo  )  [static]

Get an array of field names from a JSONObject.

Returns:
An array of field names, or null if there are no names.
String org.json.JSONObject.getString ( String  key  )  throws JSONException

Get the string associated with a key.

Parameters:
key A key string.
Returns:
A string which is the value.
Exceptions:
JSONException if the key is not found.
boolean org.json.JSONObject.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.
JSONObject org.json.JSONObject.increment ( String  key  )  throws JSONException

Increment a property of a JSONObject. If there is no such property, create one with a value of 1. If there is such a property, and if it is an Integer, Long, Double, or Float, then add one to it.

Parameters:
key A key string.
Returns:
this.
Exceptions:
JSONException If there is already a property with this name that is not an Integer, Long, Double, or Float.
boolean org.json.JSONObject.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.
Iterator org.json.JSONObject.keys (  ) 

Get an enumeration of the keys of the JSONObject.

Returns:
An iterator of the keys.
int org.json.JSONObject.length (  ) 

Get the number of keys stored in the JSONObject.

Returns:
The number of keys in the JSONObject.
JSONArray org.json.JSONObject.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.
static String org.json.JSONObject.numberToString ( Number  n  )  throws JSONException [static]

Produce a string from a Number.

Parameters:
n A Number
Returns:
A String.
Exceptions:
JSONException If n is a non-finite number.
Object org.json.JSONObject.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.
boolean org.json.JSONObject.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.
boolean org.json.JSONObject.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.
double org.json.JSONObject.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.
double org.json.JSONObject.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.
int org.json.JSONObject.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.
int org.json.JSONObject.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.
JSONArray org.json.JSONObject.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.
JSONObject org.json.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.
long org.json.JSONObject.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.
long org.json.JSONObject.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.
String org.json.JSONObject.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.
String org.json.JSONObject.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.
JSONObject org.json.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.
Exceptions:
JSONException If the value is non-finite number or if the key is null.
JSONObject org.json.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.
Exceptions:
JSONException 
JSONObject org.json.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.
Exceptions:
JSONException If the key is null.
JSONObject org.json.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.
Exceptions:
JSONException If the key is null.
JSONObject org.json.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.
Exceptions:
JSONException If the key is null or if the number is invalid.
JSONObject org.json.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.
Exceptions:
JSONException 
JSONObject org.json.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.
Exceptions:
JSONException If the key is null.
JSONObject org.json.JSONObject.putOnce ( 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, and only if there is not already a member with that name.

Parameters:
key 
value 
Returns:
his.
Exceptions:
JSONException if the key is a duplicate
JSONObject org.json.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.
Exceptions:
JSONException If the value is a non-finite number.
static String org.json.JSONObject.quote ( String  string  )  [static]

Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within </, allowing JSON text to be delivered in HTML. In JSON text, a string cannot contain a control character or an unescaped quote or backslash.

Parameters:
string A String
Returns:
A String correctly formatted for insertion in a JSON text.
Object org.json.JSONObject.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.
Iterator org.json.JSONObject.sortedKeys (  ) 

Get an enumeration of the keys of the JSONObject. The keys will be sorted alphabetically.

Returns:
An iterator of the keys.
static Object org.json.JSONObject.stringToValue ( String  s  )  [static]

Try to convert a string into a number, boolean, or null. If the string can't be converted, return the string.

Parameters:
s A String.
Returns:
A simple JSON value.
static void org.json.JSONObject.testValidity ( Object  o  )  throws JSONException [static, package]

Throw an exception if the object is an NaN or infinite number.

Parameters:
o The object to test.
Exceptions:
JSONException If o is a non-finite number.
JSONArray org.json.JSONObject.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.
Exceptions:
JSONException If any of the values are non-finite numbers.
String org.json.JSONObject.toString ( int  indentFactor,
int  indent 
) throws JSONException [package]

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.
indent The indentation of the top level.
Returns:
a printable, displayable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
Exceptions:
JSONException If the object contains an invalid number.
String org.json.JSONObject.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).
Exceptions:
JSONException If the object contains an invalid number.
String org.json.JSONObject.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.

Returns:
a printable, displayable, portable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
static String org.json.JSONObject.valueToString ( Object  value,
int  indentFactor,
int  indent 
) throws JSONException [static, package]

Make a prettyprinted JSON text of an object value.

Warning: This method assumes that the data structure is acyclical.

Parameters:
value The value to be serialized.
indentFactor The number of spaces to add to each level of indentation.
indent The indentation of the top level.
Returns:
a printable, displayable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
Exceptions:
JSONException If the object contains an invalid number.
static String org.json.JSONObject.valueToString ( Object  value  )  throws JSONException [static, package]

Make a JSON text of an Object value. If the object has an value.toJSONString() method, then that method will be used to produce the JSON text. The method is required to produce a strictly conforming text. If the object does not contain a toJSONString method (which is the most common case), then a text will be produced by other means. If the value is an array or Collection, then a JSONArray will be made from it and its toJSONString method will be called. If the value is a MAP, then a JSONObject will be made from it and its toJSONString method will be called. Otherwise, the value's toString method will be called, and the result will be quoted.

Warning: This method assumes that the data structure is acyclical.

Parameters:
value The value to be serialized.
Returns:
a printable, displayable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
Exceptions:
JSONException If the value is or contains an invalid number.
static Object org.json.JSONObject.wrap ( Object  object  )  [static, package]

Wrap an object, if necessary. If the object is null, return the NULL object. If it is an array or collection, wrap it in a JSONArray. If it is a map, wrap it in a JSONObject. If it is a standard property (Double, String, et al) then it is already wrapped. Otherwise, if it comes from one of the java packages, turn it into a string. And if it doesn't, try to wrap it in a JSONObject. If the wrapping fails, then null is returned.

Parameters:
object The object to wrap
Returns:
The wrapped value
Writer org.json.JSONObject.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.
Exceptions:
JSONException 

Member Data Documentation

final Object org.json.JSONObject.NULL = new Null() [static]

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".

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