com.restfb.json

Class JsonTokener

java.lang.Object

com.restfb.json.JsonTokener

public class JsonTokener
extends Object

A JsonTokener takes a source string and extracts characters and tokens from it. It is used by the JsonObject and JsonArray constructors to parse JSON source strings.

Version:

2008-09-18

Author:

JSON.org

Constructor Summary

Constructors

Constructor and Description
JsonTokener(Reader reader) Construct a JsonTokener from a string.
JsonTokener(String s) Construct a JsonTokener from a string.

Method Summary

Modifier and Type	Method and Description
void	back() Back up one character.
static int	dehexchar(char c) Get the hex value of a character (base16).
boolean	more() Determine if the source string still contains characters that next() can consume.
char	next() Get the next character in the source string.
char	next(char c) Consume the next character, and check that it matches a specified character.
String	next(int n) Get the next n characters.
char	nextClean() Get the next char in the string, skipping whitespace.
String	nextString(char quote) Return the characters up to the next close quote character.
String	nextTo(char d) Get the text up but not including the specified character or the end of line, whichever comes first.
String	nextTo(String delimiters) Get the text up but not including one of the specified delimiter characters or the end of line, whichever comes first.
Object	nextValue() Get the next value.
char	skipTo(char to) Skip characters until the next character is the requested character.
JsonException	syntaxError(String message) Make a JsonException to signal a syntax error.
String	toString() Make a printable string of this JsonTokener.

Methods inherited from class java.lang.Object

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

Constructor Detail

JsonTokener

public JsonTokener(Reader reader)

Construct a JsonTokener from a string.

Parameters:

reader - A reader.

JsonTokener

public JsonTokener(String s)

Construct a JsonTokener from a string.

Parameters:

s - A source string.

Method Detail

back

public void back()
          throws JsonException

Back up one character. This provides a sort of lookahead capability, so that you can test for a digit or letter before attempting to parse the next number or identifier.

Throws:

JsonException

dehexchar

public static int dehexchar(char c)

Get the hex value of a character (base16).

Parameters:

c - A character between '0' and '9' or between 'A' and 'F' or between 'a' and 'f'.

Returns:

An int between 0 and 15, or -1 if c was not a hex digit.

more

public boolean more()
             throws JsonException

Determine if the source string still contains characters that next() can consume.

Returns:

true if not yet at the end of the source.

Throws:

JsonException

next

public char next()
          throws JsonException

Get the next character in the source string.

Returns:

The next character, or 0 if past the end of the source string.

Throws:

JsonException

next

public char next(char c)
          throws JsonException

Consume the next character, and check that it matches a specified character.

Parameters:

c - The character to match.

Returns:

The character.

Throws:

JsonException - if the character does not match.

next

public String next(int n)
            throws JsonException

Get the next n characters.

Parameters:

n - The number of characters to take.

Returns:

A string of n characters.

Throws:

JsonException - Substring bounds error if there are not n characters remaining in the source string.

nextClean

public char nextClean()
               throws JsonException

Get the next char in the string, skipping whitespace.

Returns:

A character, or 0 if there are no more characters.

Throws:

JsonException

nextString

public String nextString(char quote)
                  throws JsonException

Return the characters up to the next close quote character. Backslash processing is done. The formal JSON format does not allow strings in single quotes, but an implementation is allowed to accept them.

Parameters:

quote - The quoting character, either " (double quote) or ' (single quote).

Returns:

A String.

Throws:

JsonException - Unterminated string.

nextTo

public String nextTo(char d)
              throws JsonException

Get the text up but not including the specified character or the end of line, whichever comes first.

Parameters:

d - A delimiter character.

Returns:

A string.

Throws:

JsonException

nextTo

public String nextTo(String delimiters)
              throws JsonException

Get the text up but not including one of the specified delimiter characters or the end of line, whichever comes first.

Parameters:

delimiters - A set of delimiter characters.

Returns:

A string, trimmed.

Throws:

JsonException

nextValue

public Object nextValue()
                 throws JsonException

Get the next value. The value can be a Boolean, Double, Integer, JsonArray, JsonObject, Long, or String, or the JsonObject.NULL object.

Returns:

An object.

Throws:

JsonException - If syntax error.

skipTo

public char skipTo(char to)
            throws JsonException

Skip characters until the next character is the requested character. If the requested character is not found, no characters are skipped.

Parameters:

to - A character to skip to.

Returns:

The requested character, or zero if the requested character is not found.

Throws:

JsonException

syntaxError

public JsonException syntaxError(String message)

Make a JsonException to signal a syntax error.

Parameters:

message - The error message.

Returns:

A JsonException object, suitable for throwing

toString

public String toString()

Make a printable string of this JsonTokener.

Overrides:

toString in class Object

Returns:

" at character [this.index]"