| java.lang.Object
 java.io.StreamTokenizer
| StreamTokenizer | | public class StreamTokenizer (Code) | | The StreamTokenizer class takes an input stream and
parses it into "tokens", allowing the tokens to be
read one at a time. The parsing process is controlled by a table
and a number of flags that can be set to various states. The
stream tokenizer can recognize identifiers, numbers, quoted
strings, and various comment styles.
Each byte read from the input stream is regarded as a character
in the range '\u0000' through '\u00FF'.
The character value is used to look up five possible attributes of
the character: white space, alphabetic,
numeric, string quote, and comment character.
Each character can have zero or more of these attributes.
In addition, an instance has four flags. These flags indicate:
- Whether line terminators are to be returned as tokens or treated
as white space that merely separates tokens.
- Whether C-style comments are to be recognized and skipped.
- Whether C++-style comments are to be recognized and skipped.
- Whether the characters of identifiers are converted to lowercase.
A typical application first constructs an instance of this class,
sets up the syntax tables, and then repeatedly loops calling the
nextToken method in each iteration of the loop until
it returns the value TT_EOF.
author:
James Gosling
version:
1.37, 05/03/00
See Also: java.io.StreamTokenizer.nextToken
See Also: java.io.StreamTokenizer.TT_EOF
since:
JDK1.0 |
| Field Summary | |
| final public static int | TT_EOF
A constant indicating that the end of the stream has been read. | | final public static int | TT_EOL
A constant indicating that the end of the line has been read. | | final public static int | TT_NUMBER
A constant indicating that a number token has been read. | | final public static int | TT_WORD
A constant indicating that a word token has been read. | | public double | nval
If the current token is a number, this field contains the value
of that number. | | public String | sval
If the current token is a word token, this field contains a
string giving the characters of the word token. | | public int | ttype
After a call to the nextToken method, this field
contains the type of the token just read. |
| Constructor Summary | |
| public | StreamTokenizer(Reader r)
Create a tokenizer that parses the given character stream. |
| Method Summary | |
| public void | commentChar(int ch)
Specified that the character argument starts a single-line
comment. | | 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'). | | public int | lineno()
Return the current line number. | | public void | lowerCaseMode(boolean fl)
Determines whether or not word token are automatically lowercased. | | public int | nextToken()
Parses the next token from the input stream of this tokenizer.
The type of the next token is returned in the ttype
field. | | public void | ordinaryChar(int ch)
Specifies that the character argument is "ordinary"
in this tokenizer. | | public void | ordinaryChars(int low, int hi)
Specifies that all characters c in the range
low <= c <= high
are "ordinary" in this tokenizer. | | public void | parseNumbers()
Specifies that numbers should be parsed by this tokenizer. | | 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. | | 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. | | 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. | | 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. | | 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. | | public String | toString()
Returns the string representation of the current stream token and
the line number it occurs on. | | public void | whitespaceChars(int low, int hi)
Specifies that all characters c in the range
low <= c <= high
are white space characters. | | public void | wordChars(int low, int hi)
Specifies that all characters c in the range
low <= c <= high
are word constituents. |
| TT_EOF | | final public static int TT_EOF(Code) | | A constant indicating that the end of the stream has been read.
|
| TT_EOL | | final public static int TT_EOL(Code) | | A constant indicating that the end of the line has been read.
|
| TT_NUMBER | | final public static int TT_NUMBER(Code) | | A constant indicating that a number token has been read.
|
| TT_WORD | | final public static int TT_WORD(Code) | | A constant indicating that a word token has been read.
|
| sval | | public String sval(Code) | | 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.
The initial value of this field is null.
See Also: java.io.StreamTokenizer.quoteChar(int)
See Also: java.io.StreamTokenizer.TT_WORD
See Also: java.io.StreamTokenizer.ttype |
| StreamTokenizer | | public StreamTokenizer(Reader r)(Code) | | Create a tokenizer that parses the given character stream.
Parameters:
r - a Reader object providing the input stream.
since:
JDK1.1 |
| commentChar | | public void commentChar(int ch)(Code) | | 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.
Any other attribute settings for the specified character are cleared.
Parameters:
ch - the character. |
| eolIsSignificant | | public void eolIsSignificant(boolean flag)(Code) | | 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 charactersare separate tokens; false indicates thatend-of-line characters are white space.
See Also: java.io.StreamTokenizer.nextToken
See Also: java.io.StreamTokenizer.ttype
See Also: java.io.StreamTokenizer.TT_EOL |
| lineno | | public int lineno()(Code) | | Return the current line number.
the current line number of this stream tokenizer. |
| lowerCaseMode | | public void lowerCaseMode(boolean fl)(Code) | | 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 shouldbe lowercased.
See Also: java.io.StreamTokenizer.nextToken
See Also: java.io.StreamTokenizer.ttype
See Also: java.io.StreamTokenizer.TT_WORD |
| nextToken | | public int nextToken() throws IOException(Code) | | 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.
the value of the ttype field.
exception:
IOException - if an I/O error occurs.
See Also: java.io.StreamTokenizer.nval
See Also: java.io.StreamTokenizer.sval
See Also: java.io.StreamTokenizer.ttype |
| ordinaryChar | | public void ordinaryChar(int ch)(Code) | | 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: java.io.StreamTokenizer.ttype |
| ordinaryChars | | public void ordinaryChars(int low, int hi)(Code) | | 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.
Parameters:
hi - the high end of the range.
See Also: java.io.StreamTokenizer.ordinaryChar(int) |
| parseNumbers | | public void parseNumbers()(Code) | | 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: java.io.StreamTokenizer.nval
See Also: java.io.StreamTokenizer.TT_NUMBER
See Also: java.io.StreamTokenizer.ttype |
| quoteChar | | public void quoteChar(int ch)(Code) | | 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.
Any other attribute settings for the specified character are cleared.
Parameters:
ch - the character.
See Also: java.io.StreamTokenizer.nextToken
See Also: java.io.StreamTokenizer.sval
See Also: java.io.StreamTokenizer.ttype |
| resetSyntax | | public void resetSyntax()(Code) | | 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: java.io.StreamTokenizer.ordinaryChar(int) |
| slashSlashComments | | public void slashSlashComments(boolean flag)(Code) | | 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 ignoreC++-style comments. |
| slashStarComments | | public void slashStarComments(boolean flag)(Code) | | 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 ignoreC-style comments. |
| whitespaceChars | | public void whitespaceChars(int low, int hi)(Code) | | 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.
Any other attribute settings for the characters in the specified
range are cleared.
Parameters:
low - the low end of the range.
Parameters:
hi - the high end of the range. |
| wordChars | | public void wordChars(int low, int hi)(Code) | | 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.
Parameters:
hi - the high end of the range. |
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