Android APIs
public class

JSONTokener

extends Object
java.lang.Object
   ↳ org.json.JSONTokener

Class Overview

Parses a JSON (RFC 4627) encoded string into the corresponding object. Most clients of this class will use only need the constructor and nextValue() method. Example usage:

 String json = "{"
         + "  \"query\": \"Pizza\", "
         + "  \"locations\": [ 94043, 90210 ] "
         + "}";

 JSONObject object = (JSONObject) new JSONTokener(json).nextValue();
 String query = object.getString("query");
 JSONArray locations = object.getJSONArray("locations");

For best interoperability and performance use JSON that complies with RFC 4627, such as that generated by JSONStringer. For legacy reasons this parser is lenient, so a successful parse does not indicate that the input string was valid JSON. All of the following syntax errors will be ignored:

  • End of line comments starting with // or # and ending with a newline character.
  • C-style comments starting with /* and ending with */. Such comments may not be nested.
  • Strings that are unquoted or 'single quoted'.
  • Hexadecimal integers prefixed with 0x or 0X.
  • Octal integers prefixed with 0.
  • Array elements separated by ;.
  • Unnecessary array separators. These are interpreted as if null was the omitted value.
  • Key-value pairs separated by = or =>.
  • Key-value pairs separated by ;.

Each tokener may be used to parse a single JSON string. 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.

Summary

Public Constructors
JSONTokener(String in)
Public Methods
void back()
Unreads the most recent character of input.
static int dehexchar(char hex)
Returns the integer [0..15] value for the given hex character, or -1 for non-hex input.
boolean more()
Returns true until the input has been exhausted.
String next(int length)
Returns the next length characters of the input.
char next()
Returns the next available character, or the null character '\0' if all input has been exhausted.
char next(char c)
Returns the next available character if it equals c.
char nextClean()
Returns the next character that is not whitespace and does not belong to a comment.
String nextString(char quote)
Returns the string up to but not including quote, unescaping any character escape sequences encountered along the way.
String nextTo(char excluded)
Equivalent to nextTo(String.valueOf(excluded)).
String nextTo(String excluded)
Returns the trimmed string holding the characters up to but not including the first of:
  • any character in excluded
  • a newline character '\n'
  • a carriage return '\r'

The returned string shares its backing character array with this tokener's input string.

Object nextValue()
Returns the next value from the input.
void skipPast(String thru)
Advances past all input up to and including the next occurrence of thru.
char skipTo(char to)
Advances past all input up to but not including the next occurrence of to.
JSONException syntaxError(String message)
Returns an exception containing the given message plus the current position and the entire input string.
String toString()
Returns the current position and the entire input string.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public JSONTokener (String in)

Added in API level 1

Parameters
in String: JSON encoded string. Null is not permitted and will yield a tokener that throws NullPointerExceptions when methods are called.

Public Methods

public void back ()

Added in API level 1

Unreads the most recent character of input. If no input characters have been read, the input is unchanged.

public static int dehexchar (char hex)

Added in API level 1

Returns the integer [0..15] value for the given hex character, or -1 for non-hex input.

Parameters
hex char: a character in the ranges [0-9], [A-F] or [a-f]. Any other character will yield a -1 result.
Returns
int

public boolean more ()

Added in API level 1

Returns true until the input has been exhausted.

Returns
boolean

public String next (int length)

Added in API level 1

Returns the next length characters of the input.

The returned string shares its backing character array with this tokener's input string. If a reference to the returned string may be held indefinitely, you should use new String(result) to copy it first to avoid memory leaks.

Parameters
length int
Returns
String
Throws
JSONException if the remaining input is not long enough to satisfy this request.

public char next ()

Added in API level 1

Returns the next available character, or the null character '\0' if all input has been exhausted. The return value of this method is ambiguous for JSON strings that contain the character '\0'.

Returns
char

public char next (char c)

Added in API level 1

Returns the next available character if it equals c. Otherwise an exception is thrown.

Parameters
c char
Returns
char
Throws
JSONException

public char nextClean ()

Added in API level 1

Returns the next character that is not whitespace and does not belong to a comment. If the input is exhausted before such a character can be found, the null character '\0' is returned. The return value of this method is ambiguous for JSON strings that contain the character '\0'.

Returns
char
Throws
JSONException

public String nextString (char quote)

Added in API level 1

Returns the string up to but not including quote, unescaping any character escape sequences encountered along the way. The opening quote should have already been read. This consumes the closing quote, but does not include it in the returned string.

Parameters
quote char: either ' or ".
Returns
String
Throws
JSONException

public String nextTo (char excluded)

Added in API level 1

Equivalent to nextTo(String.valueOf(excluded)).

Parameters
excluded char
Returns
String

public String nextTo (String excluded)

Added in API level 1

Returns the trimmed string holding the characters up to but not including the first of:

  • any character in excluded
  • a newline character '\n'
  • a carriage return '\r'

The returned string shares its backing character array with this tokener's input string. If a reference to the returned string may be held indefinitely, you should use new String(result) to copy it first to avoid memory leaks.

Parameters
excluded String
Returns
String a possibly-empty string

public Object nextValue ()

Added in API level 1

Returns the next value from the input.

Returns
Object a JSONObject, JSONArray, String, Boolean, Integer, Long, Double or NULL.
Throws
JSONException if the input is malformed.

public void skipPast (String thru)

Added in API level 1

Advances past all input up to and including the next occurrence of thru. If the remaining input doesn't contain thru, the input is exhausted.

Parameters
thru String

public char skipTo (char to)

Added in API level 1

Advances past all input up to but not including the next occurrence of to. If the remaining input doesn't contain to, the input is unchanged.

Parameters
to char
Returns
char

public JSONException syntaxError (String message)

Added in API level 1

Returns an exception containing the given message plus the current position and the entire input string.

Parameters
message String
Returns
JSONException

public String toString ()

Added in API level 1

Returns the current position and the entire input string.

Returns
String a printable representation of this object.