org.json

Class JSONObject

java.lang.Object

org.json.JSONObject

public class JSONObject
extends java.lang.Object

A modifiable set of name/value mappings. Names are unique, non-null strings. Values may be any mix of JSONObjects, JSONArrays, Strings, Booleans, Integers, Longs, Doubles or NULL. Values may not be null, NaNs, infinities, or of any type not listed here.

This class can coerce values to another type when requested.

• When the requested type is a boolean, strings will be coerced using a case-insensitive comparison to "true" and "false".
• When the requested type is a double, other Number types will be coerced using doubleValue. Strings that can be coerced using Double.valueOf(String) will be.
• When the requested type is an int, other Number types will be coerced using intValue. Strings that can be coerced using Double.valueOf(String) will be, and then cast to int.
• When the requested type is a long, other Number types will be coerced using longValue. Strings that can be coerced using Double.valueOf(String) will be, and then cast to long. This two-step conversion is lossy for very large values. For example, the string "9223372036854775806" yields the long 9223372036854775807.
• When the requested type is a String, other non-null values will be coerced using String.valueOf(Object). Although null cannot be coerced, the sentinel value NULL is coerced to the string "null".

This class can look up both mandatory and optional values:

• Use getType() to retrieve a mandatory value. This fails with a JSONException if the requested name has no value or if the value cannot be coerced to the requested type.
• Use optType() to retrieve an optional value. This returns a system- or user-supplied default if the requested name has no value or if the value cannot be coerced to the requested type.

Warning: this class represents null in two incompatible ways: the standard Java null reference, and the sentinel value NULL. In particular, calling put(name, null) removes the named entry from the object but put(name, JSONObject.NULL) stores an entry whose value is JSONObject.NULL.

Instances of this class are not thread safe. Although this class is nonfinal, it was not designed for inheritance and should not be subclassed. In particular, self-use by overrideable methods is not specified. See Effective Java Item 17, "Design and Document or inheritance or else prohibit it" for further information.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.ThreadLocal<java.lang.Boolean>	cyclicDepChkEnabled
static java.lang.ThreadLocal<java.util.Set>	cyclicDependencySet
static java.lang.Object	NULL A sentinel value used to explicitly define a name with no value.

Constructor Summary

Constructors

Constructor and Description
JSONObject() Creates a JSONObject with no name/value mappings.
JSONObject(JSONObject copyFrom, java.lang.String[] names) Creates a new JSONObject by copying mappings for the listed names from the given object.
JSONObject(JSONTokener readFrom) Creates a new JSONObject with name/value mappings from the next object in the tokener.
JSONObject(java.util.Map copyFrom) Creates a new JSONObject by copying all name/value mappings from the given map.
JSONObject(java.lang.Object bean) Creates a json object from a bean
JSONObject(java.lang.String json) Creates a new JSONObject with name/value mappings from the JSON string.

Method Summary

Modifier and Type	Method and Description
JSONObject	accumulate(java.lang.String name, java.lang.Object value) Appends value to the array already mapped to name.
JSONObject	append(java.lang.String name, java.lang.Object value) Appends values to the array mapped to name.
java.lang.Object	get(java.lang.String name) Returns the value mapped by name, or throws if no such mapping exists.
boolean	getBoolean(java.lang.String name) Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.
double	getDouble(java.lang.String name) Returns the value mapped by name if it exists and is a double or can be coerced to a double, or throws otherwise.
int	getInt(java.lang.String name) Returns the value mapped by name if it exists and is an int or can be coerced to an int, or throws otherwise.
JSONArray	getJSONArray(java.lang.String name) Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.
JSONObject	getJSONObject(java.lang.String name) Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.
long	getLong(java.lang.String name) Returns the value mapped by name if it exists and is a long or can be coerced to a long, or throws otherwise.
static java.lang.String[]	getNames(JSONObject x)
java.lang.String	getString(java.lang.String name) Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.
boolean	has(java.lang.String name) Returns true if this object has a mapping for name.
boolean	isNull(java.lang.String name) Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.
java.util.Iterator<java.lang.String>	keys() Returns an iterator of the String names in this object.
java.util.Set<java.lang.String>	keySet() Returns the set of String names in this object.
int	length() Returns the number of name/value mappings in this object.
JSONArray	names() Returns an array containing the string names in this object.
static java.lang.String	numberToString(java.lang.Number number) Encodes the number as a JSON string.
java.lang.Object	opt(java.lang.String name) Returns the value mapped by name, or null if no such mapping exists.
boolean	optBoolean(java.lang.String name) Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or false otherwise.
boolean	optBoolean(java.lang.String name, boolean fallback) Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or fallback otherwise.
double	optDouble(java.lang.String name) Returns the value mapped by name if it exists and is a double or can be coerced to a double, or NaN otherwise.
double	optDouble(java.lang.String name, double fallback) Returns the value mapped by name if it exists and is a double or can be coerced to a double, or fallback otherwise.
int	optInt(java.lang.String name) Returns the value mapped by name if it exists and is an int or can be coerced to an int, or 0 otherwise.
int	optInt(java.lang.String name, int fallback) Returns the value mapped by name if it exists and is an int or can be coerced to an int, or fallback otherwise.
JSONArray	optJSONArray(java.lang.String name) Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.
JSONObject	optJSONObject(java.lang.String name) Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.
long	optLong(java.lang.String name) Returns the value mapped by name if it exists and is a long or can be coerced to a long, or 0 otherwise.
long	optLong(java.lang.String name, long fallback) Returns the value mapped by name if it exists and is a long or can be coerced to a long, or fallback otherwise.
java.lang.String	optString(java.lang.String name) Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
java.lang.String	optString(java.lang.String name, java.lang.String fallback) Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.
JSONObject	put(java.lang.String name, boolean value) Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject	put(java.lang.String name, double value) Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject	put(java.lang.String name, int value) Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject	put(java.lang.String name, long value) Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject	put(java.lang.String name, java.lang.Object value) Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject	putOpt(java.lang.String name, java.lang.Object value) Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.
static java.lang.String	quote(java.lang.String data) Encodes data as a JSON string.
java.lang.Object	remove(java.lang.String name) Removes the named mapping if it exists; does nothing otherwise.
JSONArray	toJSONArray(JSONArray names) Returns an array with the values corresponding to names.
java.lang.String	toString() Encodes this object as a compact JSON string, such as:
java.lang.String	toString(int indentSpaces) Encodes this object as a human readable JSON string for debugging, such as:
static java.lang.Object	wrap(java.lang.Object o) Wraps the given object if necessary.

Methods inherited from class java.lang.Object

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

Field Detail

cyclicDependencySet

public static java.lang.ThreadLocal<java.util.Set> cyclicDependencySet

cyclicDepChkEnabled

public static java.lang.ThreadLocal<java.lang.Boolean> cyclicDepChkEnabled

NULL

public static final java.lang.Object NULL

A sentinel value used to explicitly define a name with no value. Unlike null, names with this value:

• show up in the names() array
• show up in the keys() iterator
• return true for has(String)
• do not throw on get(String)
• are included in the encoded JSON string.

This value violates the general contract of Object.equals(java.lang.Object) by returning true when compared to null. Its toString() method returns "null".

Constructor Detail

JSONObject

public JSONObject()

Creates a JSONObject with no name/value mappings.

JSONObject

public JSONObject(java.util.Map copyFrom)

Creates a new JSONObject by copying all name/value mappings from the given map.

Parameters:

copyFrom - a map whose keys are of type String and whose values are of supported types.

Throws:

java.lang.NullPointerException - if any of the map's keys are null.

JSONObject

public JSONObject(JSONTokener readFrom)
           throws JSONException

Creates a new JSONObject with name/value mappings from the next object in the tokener.

Parameters:

readFrom - a tokener whose nextValue() method will yield a JSONObject.

Throws:

JSONException - if the parse fails or doesn't yield a JSONObject.

JSONObject

public JSONObject(java.lang.String json)
           throws JSONException

Creates a new JSONObject with name/value mappings from the JSON string.

Parameters:

json - a JSON-encoded string containing an object.

Throws:

JSONException - if the parse fails or doesn't yield a JSONObject.

JSONObject

public JSONObject(JSONObject copyFrom,
                  java.lang.String[] names)
           throws JSONException

Creates a new JSONObject by copying mappings for the listed names from the given object. Names that aren't present in copyFrom will be skipped.

Parameters:

copyFrom - The source object.

names - The names of the fields to copy.

Throws:

JSONException - On internal errors. Shouldn't happen.

JSONObject

public JSONObject(java.lang.Object bean)
           throws JSONException

Creates a json object from a bean

Parameters:

bean - the bean to create the json object from

Throws:

JSONException - If there is an exception while reading the bean

Method Detail

getNames

public static java.lang.String[] getNames(JSONObject x)

length

public int length()

Returns the number of name/value mappings in this object.

Returns:

the length of this.

put

public JSONObject put(java.lang.String name,
                      boolean value)
               throws JSONException

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters:

name - The name of the value to insert.

value - The value to insert.

Returns:

this object.

Throws:

JSONException - Should not be possible.

put

public JSONObject put(java.lang.String name,
                      double value)
               throws JSONException

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters:

name - The name for the new value.

value - a finite value. May not be NaNs or infinities.

Returns:

this object.

Throws:

JSONException - if value is NaN or infinite.

put

public JSONObject put(java.lang.String name,
                      int value)
               throws JSONException

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters:

name - The name for the new value.

value - The new value.

Returns:

this object.

Throws:

JSONException - Should not be possible.

put

public JSONObject put(java.lang.String name,
                      long value)
               throws JSONException

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters:

name - The name of the new value.

value - The new value to insert.

Returns:

this object.

Throws:

JSONException - Should not be possible.

put

public JSONObject put(java.lang.String name,
                      java.lang.Object value)
               throws JSONException

Maps name to value, clobbering any existing name/value mapping with the same name. If the value is null, any existing mapping for name is removed.

Parameters:

name - The name of the new value.

value - a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities.

Returns:

this object.

Throws:

JSONException - if the value is an invalid double (infinite or NaN).

putOpt

public JSONObject putOpt(java.lang.String name,
                         java.lang.Object value)
                  throws JSONException

Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.

Parameters:

name - The name of the value to insert.

value - The value to insert.

Returns:

this object.

Throws:

JSONException - if the value is an invalid double (infinite or NaN).

accumulate

public JSONObject accumulate(java.lang.String name,
                             java.lang.Object value)
                      throws JSONException

Appends value to the array already mapped to name. If this object has no mapping for name, this inserts a new mapping. If the mapping exists but its value is not an array, the existing and new values are inserted in order into a new array which is itself mapped to name. In aggregate, this allows values to be added to a mapping one at a time. Note that append(String, Object) provides better semantics. In particular, the mapping for name will always be a JSONArray. Using accumulate will result in either a JSONArray or a mapping whose type is the type of value depending on the number of calls to it.

Parameters:

name - The name of the field to change.

value - a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL or null. May not be NaNs or infinities.

Returns:

this object after mutation.

Throws:

JSONException - If the object being added is an invalid number.

append

public JSONObject append(java.lang.String name,
                         java.lang.Object value)
                  throws JSONException

Appends values to the array mapped to name. A new JSONArray mapping for name will be inserted if no mapping exists. If the existing mapping for name is not a JSONArray, a JSONException will be thrown.

Parameters:

name - The name of the array to which the value should be appended.

value - The value to append.

Returns:

this object.

Throws:

JSONException - if name is null or if the mapping for name is non-null and is not a JSONArray.

remove

public java.lang.Object remove(java.lang.String name)

Removes the named mapping if it exists; does nothing otherwise.

Parameters:

name - The name of the mapping to remove.

Returns:

the value previously mapped by name, or null if there was no such mapping.

isNull

public boolean isNull(java.lang.String name)

Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.

Parameters:

name - The name of the value to check on.

Returns:

true if the field doesn't exist or is null.

has

public boolean has(java.lang.String name)

Returns true if this object has a mapping for name. The mapping may be NULL.

Parameters:

name - The name of the value to check on.

Returns:

true if this object has a field named name

get

public java.lang.Object get(java.lang.String name)
                     throws JSONException

Returns the value mapped by name, or throws if no such mapping exists.

Parameters:

name - The name of the value to get.

Returns:

The value.

Throws:

JSONException - if no such mapping exists.

opt

public java.lang.Object opt(java.lang.String name)

Returns the value mapped by name, or null if no such mapping exists.

Parameters:

name - The name of the value to get.

Returns:

The value.

getBoolean

public boolean getBoolean(java.lang.String name)
                   throws JSONException

Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.

Parameters:

name - The name of the field we want.

Returns:

The selected value if it exists.

Throws:

JSONException - if the mapping doesn't exist or cannot be coerced to a boolean.

optBoolean

public boolean optBoolean(java.lang.String name)

Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or false otherwise.

Parameters:

name - The name of the field we want.

Returns:

The selected value if it exists.

optBoolean

public boolean optBoolean(java.lang.String name,
                          boolean fallback)

Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or fallback otherwise.

Parameters:

name - The name of the field we want.

fallback - The value to return if the field isn't there.

Returns:

The selected value or the fallback.

getDouble

public double getDouble(java.lang.String name)
                 throws JSONException

Returns the value mapped by name if it exists and is a double or can be coerced to a double, or throws otherwise.

Parameters:

name - The name of the field we want.

Returns:

The selected value if it exists.

Throws:

JSONException - if the mapping doesn't exist or cannot be coerced to a double.

optDouble

public double optDouble(java.lang.String name)

Returns the value mapped by name if it exists and is a double or can be coerced to a double, or NaN otherwise.

Parameters:

name - The name of the field we want.

Returns:

The selected value if it exists.

optDouble

public double optDouble(java.lang.String name,
                        double fallback)

Returns the value mapped by name if it exists and is a double or can be coerced to a double, or fallback otherwise.

Parameters:

name - The name of the field we want.

fallback - The value to return if the field isn't there.

Returns:

The selected value or the fallback.

getInt

public int getInt(java.lang.String name)
           throws JSONException

Returns the value mapped by name if it exists and is an int or can be coerced to an int, or throws otherwise.

Parameters:

name - The name of the field we want.

Returns:

The selected value if it exists.

Throws:

JSONException - if the mapping doesn't exist or cannot be coerced to an int.

optInt

public int optInt(java.lang.String name)

Returns the value mapped by name if it exists and is an int or can be coerced to an int, or 0 otherwise.

Parameters:

name - The name of the field we want.

Returns:

The selected value if it exists.

optInt

public int optInt(java.lang.String name,
                  int fallback)

Returns the value mapped by name if it exists and is an int or can be coerced to an int, or fallback otherwise.

Parameters:

name - The name of the field we want.

fallback - The value to return if the field isn't there.

Returns:

The selected value or the fallback.

getLong

public long getLong(java.lang.String name)
             throws JSONException

Returns the value mapped by name if it exists and is a long or can be coerced to a long, or throws otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON without loss.

Parameters:

name - The name of the field that we want.

Returns:

The value of the field.

Throws:

JSONException - if the mapping doesn't exist or cannot be coerced to a long.

optLong

public long optLong(java.lang.String name)

Returns the value mapped by name if it exists and is a long or can be coerced to a long, or 0 otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.

Parameters:

name - The name of the field we want.

Returns:

The selected value.

optLong

public long optLong(java.lang.String name,
                    long fallback)

Returns the value mapped by name if it exists and is a long or can be coerced to a long, or fallback otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.

Parameters:

name - The name of the field we want.

fallback - The value to return if the field isn't there.

Returns:

The selected value or the fallback.

getString

public java.lang.String getString(java.lang.String name)
                           throws JSONException

Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.

Parameters:

name - The name of the field we want.

Returns:

The value of the field.

Throws:

JSONException - if no such mapping exists.

optString

public java.lang.String optString(java.lang.String name)

Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.

Parameters:

name - The name of the field we want.

Returns:

The value of the field.

optString

public java.lang.String optString(java.lang.String name,
                                  java.lang.String fallback)

Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.

Parameters:

name - The name of the field that we want.

fallback - The value to return if the field doesn't exist.

Returns:

The value of the field or fallback.

getJSONArray

public JSONArray getJSONArray(java.lang.String name)
                       throws JSONException

Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.

Parameters:

name - The field we want to get.

Returns:

The value of the field (if it is a JSONArray.

Throws:

JSONException - if the mapping doesn't exist or is not a JSONArray.

optJSONArray

public JSONArray optJSONArray(java.lang.String name)

Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.

Parameters:

name - The name of the field we want.

Returns:

The value of the specified field (assuming it is a JSNOArray

getJSONObject

public JSONObject getJSONObject(java.lang.String name)
                         throws JSONException

Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.

Parameters:

name - The name of the field that we want.

Returns:

a specified field value (if it is a JSONObject)

Throws:

JSONException - if the mapping doesn't exist or is not a JSONObject.

optJSONObject

public JSONObject optJSONObject(java.lang.String name)

Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.

Parameters:

name - The name of the value we want.

Returns:

The specified value.

toJSONArray

public JSONArray toJSONArray(JSONArray names)
                      throws JSONException

Returns an array with the values corresponding to names. The array contains null for names that aren't mapped. This method returns null if names is either null or empty.

Parameters:

names - The names of the fields that we want the values for.

Returns:

The selected values.

Throws:

JSONException - On internal errors. Shouldn't happen.

keys

public java.util.Iterator<java.lang.String> keys()

Returns an iterator of the String names in this object. The returned iterator supports remove, which will remove the corresponding mapping from this object. If this object is modified after the iterator is returned, the iterator's behavior is undefined. The order of the keys is undefined.

Returns:

an iterator over the keys.

keySet

public java.util.Set<java.lang.String> keySet()

Returns the set of String names in this object. The returned set is a view of the keys in this object. Set.remove(Object) will remove the corresponding mapping from this object and set iterator behaviour is undefined if this object is modified after it is returned. See keys().

Returns:

The names in this object.

names

public JSONArray names()

Returns an array containing the string names in this object. This method returns null if this object contains no mappings.

Returns:

the names.

toString

public java.lang.String toString()

Encodes this object as a compact JSON string, such as:

 {"query":"Pizza","locations":[94043,90210]}
 

Overrides:

toString in class java.lang.Object

toString

public java.lang.String toString(int indentSpaces)
                          throws JSONException

Encodes this object as a human readable JSON string for debugging, such as:

 {
     "query": "Pizza",
     "locations": [
         94043,
         90210
     ]
 }
 

Parameters:

indentSpaces - the number of spaces to indent for each level of nesting.

Returns:

The string containing the pretty form of this.

Throws:

JSONException - On internal errors. Shouldn't happen.

numberToString

public static java.lang.String numberToString(java.lang.Number number)
                                       throws JSONException

Encodes the number as a JSON string.

Parameters:

number - a finite value. May not be NaNs or infinities.

Returns:

The encoded number in string form.

Throws:

JSONException - On internal errors. Shouldn't happen.

quote

public static java.lang.String quote(java.lang.String data)

Encodes data as a JSON string. This applies quotes and any necessary character escaping.

Parameters:

data - the string to encode. Null will be interpreted as an empty string.

Returns:

the quoted string.

wrap

public static java.lang.Object wrap(java.lang.Object o)

Wraps the given object if necessary.

If the object is null or , returns NULL. If the object is a JSONArray or JSONObject, no wrapping is necessary. If the object is NULL, no wrapping is necessary. If the object is an array or Collection, returns an equivalent JSONArray. If the object is a Map, returns an equivalent JSONObject. If the object is a primitive wrapper type or String, returns the object. If the object is from a java package, returns the result of toString. If the object is some other kind of object then it is assumed to be a bean and is converted to a JSONObject. If wrapping fails, returns null.

Parameters:

o - The object to wrap.

Returns:

The wrapped (if necessary) form of the object {$code o}