org.json.stream

Class JSONLexer

java.lang.Object

org.json.stream.JSONLexer

public final class JSONLexer
extends java.lang.Object

A JSONLexer takes a source stream and extracts characters and tokens from it. It does not perform any sanity checks on the order that tokens appear. It is used by JSONStreamReader class to tokenise JSON source streams.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JSONLexer.Token Tokens that can be identified with at most one character lookahead.

Constructor Summary

Constructors

Constructor and Description
JSONLexer(java.io.InputStream inputStream, java.nio.charset.Charset charset) Construct a JSONLexer from an InputStream and a supplied Charset.
JSONLexer(java.io.Reader reader) Construct a JSONLexer from a Reader.
JSONLexer(java.lang.String s) Construct a JSONLexer from a String.

Method Summary

Modifier and Type	Method and Description
boolean	nextNumber(java.lang.Appendable sb) Parse a number strictly according to the JSON specification.
boolean	nextNumber(java.lang.Appendable sb, int mDigits, int eDigits) Parse a number strictly according to the JSON specification.
<T extends java.lang.Appendable> T	nextString(T sb) Return the characters up to the next close quote character.
<T extends java.lang.Appendable> T	nextString(T sb, long maxLen) Return the characters up to the next close quote character.
JSONLexer.Token	nextTokenType() Get the type of the next token in the stream, skipping whitespace.
ParsePosition	parsePosition() Indicates the current position of the scanner.
void	skipNumber() Skip a number strictly according to the JSON specification.
void	skipString() Skip the characters up to the next close quote character.
java.lang.String	toString() Make a printable string of this JSONLexer.

Methods inherited from class java.lang.Object

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

Constructor Detail

JSONLexer

public JSONLexer(java.io.Reader reader)

Construct a JSONLexer from a Reader.

Parameters:

reader - A reader.

JSONLexer

public JSONLexer(java.io.InputStream inputStream,
                 java.nio.charset.Charset charset)

Construct a JSONLexer from an InputStream and a supplied Charset.

Parameters:

inputStream - the input stream containing the JSON data

charset - the character set with which to interpret the input stream

JSONLexer

public JSONLexer(java.lang.String s)

Construct a JSONLexer from a String.

Parameters:

s - A source string.

Method Detail

nextTokenType

public JSONLexer.Token nextTokenType()
                              throws JSONException

Get the type of the next token in the stream, skipping whitespace. This parses the literal tokens and separators only.

Returns:

the Token type representing the next token type

Throws:

JSONException

nextString

public <T extends java.lang.Appendable> T nextString(T sb)
                                              throws JSONException

Return the characters up to the next close quote character. Backslash escape sequences are processed. The formal JSON format only allows string values within double quotes.

Type Parameters:

T - a subtype of Appendable, returned to the caller for chaining purposes

Parameters:

sb - the Appendable to which the String value is appended

Returns:

the supplied Appendable object

Throws:

JSONException - Unterminated string.

nextString

public <T extends java.lang.Appendable> T nextString(T sb,
                                                     long maxLen)
                                              throws JSONException

Return the characters up to the next close quote character. Backslash escape sequences are processed. The formal JSON format only allows string values within double quotes.

Most practical parsers will limit the length of a string to one expressible by a String object, or writable to a File.

Type Parameters:

T - a subtype of Appendable, returned to the caller for chaining purposes

Parameters:

sb - the Appendable to which the String value is appended

maxLen - the maximum length of the decoded string value, <= 0 to limit to Long.MAX_VALUE

Returns:

the supplied Appendable object

Throws:

JSONException - Unterminated string.

skipString

public void skipString()
                throws JSONException

Skip the characters up to the next close quote character. Backslash processing is done. The formal JSON format only allows strings in double quotes.

Throws:

JSONException - Unterminated string.

nextNumber

public boolean nextNumber(java.lang.Appendable sb)
                   throws JSONException

Parse a number strictly according to the JSON specification.

Parameters:

sb - The Appendable to which the parsed character sequence is appended

Returns:

true if the number is a floating point value, otherwise false to indicate an integer value

Throws:

JSONException

nextNumber

public boolean nextNumber(java.lang.Appendable sb,
                          int mDigits,
                          int eDigits)
                   throws JSONException

Parse a number strictly according to the JSON specification.

Most practical JSON parsers limit the number values to those expressible by Long or Double values.

Parameters:

sb - The Appendable to which the parsed character sequence is appended

mDigits - maximum number of mantissa digits to be parsed, <= 0 to limit to Integer.MAX_VALUE

eDigits - maximum number of exponent digits to be parsed, 0 for no exponent, or < 0 to limit to Integer.MAX_VALUE

Returns:

true if the number is a floating point value, otherwise false to indicate an integer value

Throws:

JSONException

skipNumber

public void skipNumber()
                throws JSONException

Skip a number strictly according to the JSON specification.

Throws:

JSONException

parsePosition

public ParsePosition parsePosition()

Indicates the current position of the scanner.

Returns:

a ParsePosition representing the current location of the scanner

toString

public java.lang.String toString()

Make a printable string of this JSONLexer.

Overrides:

toString in class java.lang.Object

Returns:

"JSONLexer at {index} [character {character} line {line}]"