org.monte.media.io

Class StreamPosTokenizer

java.lang.Object

org.monte.media.io.StreamPosTokenizer

public class StreamPosTokenizer
extends Object

This extension of StreamTokenizer keeps track of the position of the tokens in the input stream, and it can parse hexadecimal numbers and double numbers with exponents.

The handling of numeric data is also different: a single dot '.' and minus dot '-.' are not treated as numbers.

Version:

$Id: StreamPosTokenizer.java 299 2013-01-03 07:40:18Z werner $

Author:

Werner Randelshofer, Hausmatt 10, Goldau, CH-6405, Switzerland

Field Summary

Fields

Modifier and Type	Field and Description
double	nval If the current token is a number, this field contains the value of that number.
String	sval If the current token is a word token, this field contains a string giving the characters of the word token.
static int	TT_EOF A constant indicating that the end of the stream has been read.
static int	TT_EOL A constant indicating that the end of the line has been read.
static int	TT_NUMBER A constant indicating that a number token has been read.
static int	TT_WORD A constant indicating that a word token has been read.
int	ttype After a call to the nextToken method, this field contains the type of the token just read.

Constructor Summary

Constructors

Constructor and Description
StreamPosTokenizer() Initializes everything except the streams.
StreamPosTokenizer(Reader r) Create a tokenizer that parses the given character stream.

Method Summary

Methods

Modifier and Type	Method and Description
void	commentChar(int ch) Specified that the character argument starts a single-line comment.
void	consumeGreedy(String greedyToken) Consumes a substring from the current sval of the StreamPosTokenizer.
void	eolIsSignificant(boolean flag) Determines whether or not ends of line are treated as tokens.
int	getEndPosition() Returns the end position of the token relative to the position that the stream had, when the StreamPosTokenizer was constructed.
int	getStartPosition() Returns the start position of the token relative to the position that the stream had, when the StreamPosTokenizer was constructed.
int	lineno() Return the current line number.
void	lowerCaseMode(boolean fl) Determines whether or not word token are automatically lowercased.
int	nextChar() Reads the next character from the input stream, without passing it to the tokenizer.
int	nextToken() Parses the next token from the input stream of this tokenizer.
void	ordinaryChar(int ch) Specifies that the character argument is "ordinary" in this tokenizer.
void	ordinaryChars(int low, int hi) Specifies that all characters c in the range low <= c <= high are "ordinary" in this tokenizer.
void	parseExponents() Enables number parsing of exponents.
void	parseHexNumbers() Enables number parsing for decimal numbers and for hexadecimal numbers
void	parseNumbers() Specifies that numbers should be parsed by this tokenizer.
void	parsePlusAsNumber()
void	pushBack() Causes the next call to the nextToken method of this tokenizer to return the current value in the ttype field, and not to modify the value in the nval or sval field.
void	pushCharBack(int ch) Unreads a character back into the input stream of the tokenizer.
void	quoteChar(int ch) Specifies that matching pairs of this character delimit string constants in this tokenizer.
void	resetSyntax() Resets this tokenizer's syntax table so that all characters are "ordinary." See the ordinaryChar method for more information on a character being ordinary.
void	setReader(Reader r) Sets the reader for the tokenizer.
void	setSlashSlashToken(String slashSlash) Sets the slash slash token.
void	setSlashStarTokens(String slashStar, String starSlash) Sets the slash star and star slash tokens.
void	setStartPosition(int p) Set the start position of the current token.
void	slashSlashComments(boolean flag) Determines whether or not the tokenizer recognizes C++-style comments.
void	slashStarComments(boolean flag) Determines whether or not the tokenizer recognizes C-style comments.
String	toString() Returns the string representation of the current stream token.
void	whitespaceChars(int low, int hi) Specifies that all characters c in the range low <= c <= high are white space characters.
void	wordChars(int low, int hi) Specifies that all characters c in the range low <= c <= high are word constituents.

Methods inherited from class java.lang.Object

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

Field Detail

ttype

public int ttype

After a call to the nextToken method, this field contains the type of the token just read. For a single character token, its value is the single character, converted to an integer. For a quoted string token (see , its value is the quote character. Otherwise, its value is one of the following:

• TT_WORD indicates that the token is a word.
• TT_NUMBER indicates that the token is a number.
• TT_EOL indicates that the end of line has been read. The field can only have this value if the eolIsSignificant method has been called with the argument true.
• TT_EOF indicates that the end of the input stream has been reached.

See Also:

StreamTokenizer.eolIsSignificant(boolean), StreamTokenizer.nextToken(), StreamTokenizer.quoteChar(int), StreamTokenizer.TT_EOF, StreamTokenizer.TT_EOL, StreamTokenizer.TT_NUMBER, StreamTokenizer.TT_WORD

TT_EOF

public static final int TT_EOF

A constant indicating that the end of the stream has been read.

See Also:

Constant Field Values

TT_EOL

public static final int TT_EOL

A constant indicating that the end of the line has been read.

See Also:

Constant Field Values

TT_NUMBER

public static final int TT_NUMBER

A constant indicating that a number token has been read.

See Also:

Constant Field Values

TT_WORD

public static final int TT_WORD

A constant indicating that a word token has been read.

See Also:

Constant Field Values

sval

public String sval

If the current token is a word token, this field contains a string giving the characters of the word token. When the current token is a quoted string token, this field contains the body of the string.

The current token is a word when the value of the ttype field is TT_WORD. The current token is a quoted string token when the value of the ttype field is a quote character.

See Also:

StreamTokenizer.quoteChar(int), StreamTokenizer.TT_WORD, StreamTokenizer.ttype

nval

public double nval

If the current token is a number, this field contains the value of that number. The current token is a number when the value of the ttype field is TT_NUMBER.

See Also:

StreamTokenizer.TT_NUMBER, StreamTokenizer.ttype

Constructor Detail

StreamPosTokenizer

public StreamPosTokenizer()

Initializes everything except the streams.

StreamPosTokenizer

public StreamPosTokenizer(Reader r)

Create a tokenizer that parses the given character stream.

Since:

JDK1.1

Method Detail

setReader

public void setReader(Reader r)

Sets the reader for the tokenizer.

Parameters:

r -

resetSyntax

public void resetSyntax()

Resets this tokenizer's syntax table so that all characters are "ordinary." See the ordinaryChar method for more information on a character being ordinary.

See Also:

StreamTokenizer.ordinaryChar(int)

wordChars

public void wordChars(int low,
             int hi)

Specifies that all characters c in the range low <= c <= high are word constituents. A word token consists of a word constituent followed by zero or more word constituents or number constituents.

Parameters:

low - the low end of the range.

hi - the high end of the range.

whitespaceChars

public void whitespaceChars(int low,
                   int hi)

Specifies that all characters c in the range low <= c <= high are white space characters. White space characters serve only to separate tokens in the input stream.

Parameters:

low - the low end of the range.

hi - the high end of the range.

ordinaryChars

public void ordinaryChars(int low,
                 int hi)

Specifies that all characters c in the range low <= c <= high are "ordinary" in this tokenizer. See the ordinaryChar method for more information on a character being ordinary.

Parameters:

low - the low end of the range.

hi - the high end of the range.

See Also:

StreamTokenizer.ordinaryChar(int)

ordinaryChar

public void ordinaryChar(int ch)

Specifies that the character argument is "ordinary" in this tokenizer. It removes any special significance the character has as a comment character, word component, string delimiter, white space, or number character. When such a character is encountered by the parser, the parser treates it as a single-character token and sets ttype field to the character value.

Parameters:

ch - the character.

See Also:

StreamTokenizer.ttype

commentChar

public void commentChar(int ch)

Specified that the character argument starts a single-line comment. All characters from the comment character to the end of the line are ignored by this stream tokenizer.

Parameters:

ch - the character.

quoteChar

public void quoteChar(int ch)

Specifies that matching pairs of this character delimit string constants in this tokenizer.

When the nextToken method encounters a string constant, the ttype field is set to the string delimiter and the sval field is set to the body of the string.

If a string quote character is encountered, then a string is recognized, consisting of all characters after (but not including) the string quote character, up to (but not including) the next occurrence of that same string quote character, or a line terminator, or end of file. The usual escape sequences such as "\n" and "\t" are recognized and converted to single characters as the string is parsed.

Parameters:

ch - the character.

See Also:

StreamTokenizer.nextToken(), StreamTokenizer.sval, StreamTokenizer.ttype

parseNumbers

public void parseNumbers()

Specifies that numbers should be parsed by this tokenizer. The syntax table of this tokenizer is modified so that each of the twelve characters:

      0 1 2 3 4 5 6 7 8 9 . -
 

has the "numeric" attribute.

When the parser encounters a word token that has the format of a double precision floating-point number, it treats the token as a number rather than a word, by setting the the ttype field to the value TT_NUMBER and putting the numeric value of the token into the nval field.

See Also:

StreamTokenizer.nval, StreamTokenizer.TT_NUMBER, StreamTokenizer.ttype

parsePlusAsNumber

public void parsePlusAsNumber()

parseHexNumbers

public void parseHexNumbers()

Enables number parsing for decimal numbers and for hexadecimal numbers

parseExponents

public void parseExponents()

Enables number parsing of exponents. Exponents appear after the last digit of number with capital letter 'E' or small letter 'e'.

eolIsSignificant

public void eolIsSignificant(boolean flag)

Determines whether or not ends of line are treated as tokens. If the flag argument is true, this tokenizer treats end of lines as tokens; the nextToken method returns TT_EOL and also sets the ttype field to this value when an end of line is read.

A line is a sequence of characters ending with either a carriage-return character ('\r') or a newline character ('\n'). In addition, a carriage-return character followed immediately by a newline character is treated as a single end-of-line token.

If the flag is false, end-of-line characters are treated as white space and serve only to separate tokens.

Parameters:

flag - true indicates that end-of-line characters are separate tokens; false indicates that end-of-line characters are white space.

See Also:

StreamTokenizer.nextToken(), StreamTokenizer.ttype, StreamTokenizer.TT_EOL

slashStarComments

public void slashStarComments(boolean flag)

Determines whether or not the tokenizer recognizes C-style comments. If the flag argument is true, this stream tokenizer recognizes C-style comments. All text between successive occurrences of /* and */ are discarded.

If the flag argument is false, then C-style comments are not treated specially.

Parameters:

flag - true indicates to recognize and ignore C-style comments.

slashSlashComments

public void slashSlashComments(boolean flag)

Determines whether or not the tokenizer recognizes C++-style comments. If the flag argument is true, this stream tokenizer recognizes C++-style comments. Any occurrence of two consecutive slash characters ('/') is treated as the beginning of a comment that extends to the end of the line.

If the flag argument is false, then C++-style comments are not treated specially.

Parameters:

flag - true indicates to recognize and ignore C++-style comments.

lowerCaseMode

public void lowerCaseMode(boolean fl)

Determines whether or not word token are automatically lowercased. If the flag argument is true, then the value in the sval field is lowercased whenever a word token is returned (the ttype field has the value TT_WORD by the nextToken method of this tokenizer.

If the flag argument is false, then the sval field is not modified.

Parameters:

fl - true indicates that all word tokens should be lowercased.

See Also:

StreamTokenizer.nextToken(), StreamTokenizer.ttype, StreamTokenizer.TT_WORD

nextToken

public int nextToken()
              throws IOException

Parses the next token from the input stream of this tokenizer. The type of the next token is returned in the ttype field. Additional information about the token may be in the nval field or the sval field of this tokenizer.

Typical clients of this class first set up the syntax tables and then sit in a loop calling nextToken to parse successive tokens until TT_EOF is returned.

Returns:

the value of the ttype field.

Throws:

IOException - if an I/O error occurs.

See Also:

StreamTokenizer.nval, StreamTokenizer.sval, StreamTokenizer.ttype

nextChar

public int nextChar()
             throws IOException

Reads the next character from the input stream, without passing it to the tokenizer.

Throws:

IOException

pushCharBack

public void pushCharBack(int ch)
                  throws IOException

Unreads a character back into the input stream of the tokenizer.

Throws:

IOException

setSlashStarTokens

public void setSlashStarTokens(String slashStar,
                      String starSlash)

Sets the slash star and star slash tokens. Due to limitations by this implementation, both tokens must have the same number of characters and the character length must be either 1 or 2.

setSlashSlashToken

public void setSlashSlashToken(String slashSlash)

Sets the slash slash token. Due to limitations by this implementation, the character length must be either 1 or 2.

pushBack

public void pushBack()

Causes the next call to the nextToken method of this tokenizer to return the current value in the ttype field, and not to modify the value in the nval or sval field.

See Also:

StreamTokenizer.nextToken(), StreamTokenizer.nval, StreamTokenizer.sval, StreamTokenizer.ttype

lineno

public int lineno()

Return the current line number.

Returns:

the current line number of this stream tokenizer.

getStartPosition

public int getStartPosition()

Returns the start position of the token relative to the position that the stream had, when the StreamPosTokenizer was constructed.

Returns:

the start position of the token.

setStartPosition

public void setStartPosition(int p)

Set the start position of the current token.

getEndPosition

public int getEndPosition()

Returns the end position of the token relative to the position that the stream had, when the StreamPosTokenizer was constructed.

Returns:

the end position of the token.

consumeGreedy

public void consumeGreedy(String greedyToken)

Consumes a substring from the current sval of the StreamPosTokenizer.

toString

public String toString()

Returns the string representation of the current stream token.

Overrides:

toString in class Object

Returns:

a string representation of the token specified by the ttype, nval, and sval fields.

See Also:

StreamTokenizer.nval, StreamTokenizer.sval, StreamTokenizer.ttype