JSONStringer

AI-generated Key Takeaways

• JSONStringer is a utility for manually building JSON strings but most developers should use JSONObject.toString() or JSONArray.toString() instead.

• It enforces strict JSON structure rules, such as balanced scopes and correct key-value pairs, throwing a JSONException for violations.

• While it provides methods for building JSON arrays and objects, it doesn't handle pretty-printing, for which the toString(int) methods of JSONObject and JSONArray should be used.

• Note that nesting is limited and excessive nesting might lead to a JSONException.

• Instances of JSONStringer are not thread-safe and should not be shared between threads.

public class JSONStringer extends Object

Implements JSONObject.toString() and JSONArray.toString(). Most application developers should use those methods directly and disregard this API. For example:

 JSONObject object = ...
 String json = object.toString();

Stringers only encode well-formed JSON strings. In particular:

• The stringer must have exactly one top-level array or object.
• Lexical scopes must be balanced: every call to array() must have a matching call to endArray() and every call to object() must have a matching call to endObject().
• Arrays may not contain keys (property names).
• Objects must alternate keys (property names) and values.
• Values are inserted with either literal value calls, or by nesting arrays or objects.

Calls that would result in a malformed JSON string will fail with a JSONException.

This class provides no facility for pretty-printing (ie. indenting) output. To encode indented output, use JSONObject.toString(int) or JSONArray.toString(int).

Some implementations of the API support at most 20 levels of nesting. Attempts to create more than 20 levels of nesting may fail with a JSONException.

Each stringer may be used to encode a single top level value. 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.

Public Constructor Summary

JSONStringer()

Public Method Summary

JSONStringer	array() Begins encoding a new array.
JSONStringer	endArray() Ends encoding the current array.
JSONStringer	endObject() Ends encoding the current object.
JSONStringer	key(String name) Encodes the key (property name) to this stringer.
JSONStringer	object() Begins encoding a new object.
String	toString() Returns the encoded JSON string.
JSONStringer	value(long value) Encodes value to this stringer.
JSONStringer	value(double value) Encodes value to this stringer.
JSONStringer	value(boolean value) Encodes value to this stringer.
JSONStringer	value(Object value) Encodes value.

Inherited Method Summary

From class java.lang.Object

Object	clone()
boolean	equals(Object arg0)
void	finalize()
final Class<?>	getClass()
int	hashCode()
final void	notify()
final void	notifyAll()
String	toString()
final void	wait(long arg0, int arg1)
final void	wait(long arg0)
final void	wait()

Public Constructors

public JSONStringer ()

Public Methods

public JSONStringer array ()

Begins encoding a new array. Each call to this method must be paired with a call to endArray().

Returns

• this stringer.

Throws

JSONException

public JSONStringer endArray ()

Ends encoding the current array.

Returns

• this stringer.

Throws

JSONException

public JSONStringer endObject ()

Ends encoding the current object.

Returns

• this stringer.

Throws

JSONException

public JSONStringer key (String name)

Encodes the key (property name) to this stringer.

Parameters

name	the name of the forthcoming value. May not be null.

Returns

• this stringer.

Throws

JSONException

public JSONStringer object ()

Begins encoding a new object. Each call to this method must be paired with a call to endObject().

Returns

• this stringer.

Throws

JSONException

public String toString ()

Returns the encoded JSON string.

If invoked with unterminated arrays or unclosed objects, this method's return value is undefined.

Warning: although it contradicts the general contract of Object.toString(), this method returns null if the stringer contains no data.

public JSONStringer value (long value)

Encodes value to this stringer.

Parameters

value

Returns

• this stringer.

Throws

JSONException

public JSONStringer value (double value)

Encodes value to this stringer.

Parameters

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

Returns

• this stringer.

Throws

JSONException

public JSONStringer value (boolean value)

Encodes value to this stringer.

Parameters

value

Returns

• this stringer.

Throws

JSONException

public JSONStringer value (Object value)

Encodes value.

Parameters

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

Returns

• this stringer.

Throws

JSONException