Module org.jhotdraw8.base
Package org.jhotdraw8.base.io

Class StreamPosTokenizer

java.lang.Object
org.jhotdraw8.base.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.

Author:
Werner Randelshofer

  • Field Summary

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

  • Constructor Summary

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

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    commentChar(int ch)
    Specified that the character argument starts a single-line comment.
    void
    consumeGreedy(@NonNull String greedyToken)
    Consumes a substring from the current sval of the StreamPosTokenizer.
    ParseException
    createException(String errorMessage)
     
    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 next 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
    requireNextToken(int ttype, String errorMessage)
     
    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(@NonNull Reader r)
    Sets the reader for the tokenizer.
    void
    setSlashSlashToken(@NonNull String slashSlash)
    Sets the slash slash token.
    void
    setSlashStarTokens(@NonNull String slashStar, @NonNull 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.
    @NonNull 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 Details

    • ttype

      public int ttype
      After a call to the next 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:

    • TT_EOF

      public static final int TT_EOF
      A constant indicating that the end of the stream has been read.
      See Also:

    • TT_EOL

      public static final int TT_EOL
      A constant indicating that the end of the line has been read.
      See Also:

    • TT_NUMBER

      public static final int TT_NUMBER
      A constant indicating that a number token has been read.
      See Also:

    • TT_WORD

      public static final int TT_WORD
      A constant indicating that a word token has been read.
      See Also:

    • sval

      public @Nullable 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:

    • 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:

  • Constructor Details

    • StreamPosTokenizer

      public StreamPosTokenizer()
      Initializes everything except the streams.

    • StreamPosTokenizer

      public StreamPosTokenizer(@NonNull Reader r)
      Create a tokenizer that parses the given character stream.
      Parameters:
      r - the reader

    • StreamPosTokenizer

      public StreamPosTokenizer(CharSequence r)
      Create a tokenizer that parses the given character stream.
      Parameters:
      r - the reader

  • Method Details

    • setReader

      public void setReader(@NonNull Reader r)
      Sets the reader for the tokenizer.
      Parameters:
      r - The reader

    • 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:

    • 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:

    • 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:

    • 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 next 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:

    • 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:

    • 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 next 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:

    • 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 next 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:

    • requireNextToken

      public void requireNextToken(int ttype, String errorMessage) throws ParseException, IOException
      Throws:
      ParseException
      IOException

    • createException

      public ParseException createException(String errorMessage)

    • 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 next 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:

    • nextChar

      public int nextChar() throws IOException
      Reads the next character from the input stream, without passing it to the tokenizer.
      Returns:
      the next char
      Throws:
      IOException - in case of an IO error

    • pushCharBack

      public void pushCharBack(int ch)
      Unreads a character back into the input stream of the tokenizer.
      Parameters:
      ch - The character

    • setSlashStarTokens

      public void setSlashStarTokens(@NonNull String slashStar, @NonNull 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.
      Parameters:
      slashStar - token
      starSlash - token

    • setSlashSlashToken

      public void setSlashSlashToken(@NonNull String slashSlash)
      Sets the slash slash token. Due to limitations by this implementation, the character length must be either 1 or 2.
      Parameters:
      slashSlash - token

    • pushBack

      public void pushBack()
      Causes the next call to the next 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:

    • 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.
      Parameters:
      p - the position

    • 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(@NonNull String greedyToken)
      Consumes a substring from the current sval of the StreamPosTokenizer.
      Parameters:
      greedyToken - the token to be consumed

    • toString

      public @NonNull 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: