Package org.scictrl.mp.orbitcorrect.accessories

Class FileTokenizer

java.lang.Object
org.scictrl.mp.orbitcorrect.accessories.FileTokenizer
public class FileTokenizer extends Object
The FileTokenizer 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. FileTokenizer uses StreamTokenizer and its methodes.
Author:
igor@scictrl.com

  • 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.
    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 file 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 nextToken method, this field contains the type of the token just read.

  • Constructor Summary

    Constructors
    Constructor
    Description
    FileTokenizer(File file)
    Creates new FileTokenizer that parses the specified file..
    FileTokenizer(Reader reader, URL url)
    Constructor for FileTokenizer.
    FileTokenizer(URL url)
    Creates new FileTokenizer that parses the specified file..

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Closes Reader.File is opened with InputStreamReader in constructor of this class.
    void
    commentChar(int ch)
    Specified that the character argument starts a single-line comment.
    void
    eolIsSignificant(boolean flag)
    Determines whether or not ends of line are treated as tokens.
    URL
    getURL()
    Returns URL.
    int
    lineno()
    Return the current line number.
    void
    lowerCaseMode(boolean fl)
    Determines whether or not word token are automatically lowercased.
    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
    parseNumbers()
    Specifies that numbers should be parsed by this tokenizer.
    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
    quoteChar(int ch)
    Specifies that matching pairs of this character delimit string constants in this tokenizer.
    void
    setURL(URL u)
    Sets URL to new value.
    void
    skipLine()
    Moves reading position to end of current line.
    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()
    Returnes information about unknown source from where FileTokenizer should read.
    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 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:

    • 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:

    • 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:

    • TT_EOF

      public static final int TT_EOF
      A constant indicating that the end of the file 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:

  • Constructor Details

    • FileTokenizer

      public FileTokenizer(File file) throws FileNotFoundException
      Creates new FileTokenizer that parses the specified file..
      Parameters:
      file - a File object
      Throws:
      FileNotFoundException - if any.

    • FileTokenizer

      public FileTokenizer(Reader reader, URL url) throws IOException

      Constructor for FileTokenizer.

      Parameters:
      reader - a Reader object
      url - a URL object
      Throws:
      IOException - if any.

    • FileTokenizer

      public FileTokenizer(URL url) throws IOException
      Creates new FileTokenizer that parses the specified file..
      Parameters:
      url - a URL object
      Throws:
      IOException - if any.

  • Method Details

    • close

      public void close() throws IOException
      Closes Reader.File is opened with InputStreamReader in constructor of this class.
      Throws:
      IOException - if any.
      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.

    • 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:

    • getURL

      public URL getURL()
      Returns URL.
      Returns:
      java.net.URL

    • lineno

      public int lineno()
      Return the current line number.
      Returns:
      the current line number of this stream tokenizer.

    • 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:

    • 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.
      Returns:
      a int
      Throws:
      IOException - if any.

    • 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:

    • 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:

    • 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:

    • 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:

    • setURL

      public void setURL(URL u)
      Sets URL to new value.
      Parameters:
      u - java.net.URL

    • skipLine

      public void skipLine() throws IOException, ParseException
      Moves reading position to end of current line. ttype field becomes TT_EOL. Next call to nextToken() will return first token in next line.
      Throws:
      IOException - if any.
      ParseException - if any.

    • 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.

    • 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.

    • toString

      public String toString()
      Returnes information about unknown source from where FileTokenizer should read.
      Overrides:
      toString in class Object

    • 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.

    • 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.