Package org.fife.ui.rsyntaxtextarea.modes

Class PlainTextTokenMaker

  • All Implemented Interfaces:
    TokenMaker
    public class PlainTextTokenMaker
extends AbstractJFlexTokenMaker
    Scanner for plain text files. This implementation was created using JFlex 1.4.1; however, the generated file was modified for performance. Memory allocation needs to be almost completely removed to be competitive with the handwritten lexers (subclasses of AbstractTokenMaker), so this class has been modified so that Strings are never allocated (via yytext()), and the scanner never has to worry about refilling its buffer (needlessly copying chars around). We can achieve this because RText always scans exactly 1 line of tokens at a time, and hands the scanner this line as an array of characters (a Segment really). Since tokens contain pointers to char arrays instead of Strings holding their contents, there is no need for allocating new memory for Strings.

    The actual algorithm generated for scanning has, of course, not been modified.

    If you wish to regenerate this file yourself, keep in mind the following:

    • The generated PlainTextTokenMaker.java file will contain two definitions of both zzRefill and yyreset. You should hand-delete the second of each definition (the ones generated by the lexer), as these generated methods modify the input buffer, which we'll never have to do.
    • You should also change the declaration/definition of zzBuffer to NOT be initialized. This is a needless memory allocation for us since we will be pointing the array somewhere else anyway.
    • You should NOT call yylex() on the generated scanner directly; rather, you should use getTokenList as you would with any other TokenMaker instance.

    • Constructor Detail

      • PlainTextTokenMaker

        public PlainTextTokenMaker()
        Constructor. This must be here because JFlex does not generate a no-parameter constructor.

      • PlainTextTokenMaker

        public PlainTextTokenMaker​(Reader in)
        Creates a new scanner There is also a java.io.InputStream version of this constructor.
        Parameters:
        in - the java.io.Reader to read input from.

      • PlainTextTokenMaker

        public PlainTextTokenMaker​(InputStream in)
        Creates a new scanner. There is also java.io.Reader version of this constructor.
        Parameters:
        in - the java.io.Inputstream to read input from.

    • Method Detail

      • getLastTokenTypeOnLine

        public int getLastTokenTypeOnLine​(Segment text,
                                  int initialTokenType)
        Always returns Token.NULL, as there are no multiline tokens in properties files.
        Specified by:
        getLastTokenTypeOnLine in interface TokenMaker
        Overrides:
        getLastTokenTypeOnLine in class TokenMakerBase
        Parameters:
        text - The line of tokens to examine.
        initialTokenType - The token type to start with (i.e., the value of getLastTokenTypeOnLine for the line before text).
        Returns:
        Token.NULL.

      • getLineCommentStartAndEnd

        public String[] getLineCommentStartAndEnd​(int languageIndex)
        Returns the text to place at the beginning and end of a line to "comment" it in a this programming language.
        Specified by:
        getLineCommentStartAndEnd in interface TokenMaker
        Overrides:
        getLineCommentStartAndEnd in class TokenMakerBase
        Parameters:
        languageIndex - The language index at the offset in question. Since some TokenMakers effectively have nested languages (such as JavaScript in HTML), this parameter tells the TokenMaker what sub-language to look at.
        Returns:
        null, as there are no comments in plain text.

      • getMarkOccurrencesOfTokenType

        public boolean getMarkOccurrencesOfTokenType​(int type)
        Always returns false, as you never want "mark occurrences" working in plain text files.
        Specified by:
        getMarkOccurrencesOfTokenType in interface TokenMaker
        Overrides:
        getMarkOccurrencesOfTokenType in class TokenMakerBase
        Parameters:
        type - The token type.
        Returns:
        Whether tokens of this type should have "mark occurrences" enabled.

      • getTokenList

        public Token getTokenList​(Segment text,
                          int initialTokenType,
                          int startOffset)
        Returns the first token in the linked list of tokens generated from text. This method must be implemented by subclasses so they can correctly implement syntax highlighting.
        Parameters:
        text - The text from which to get tokens.
        initialTokenType - The token type we should start with.
        startOffset - The offset into the document at which text starts.
        Returns:
        The first Token in a linked list representing the syntax highlighted text.

      • yyreset

        public final void yyreset​(Reader reader)
        Resets the scanner to read from a new input stream. Does not close the old reader. All internal variables are reset, the old input stream cannot be reused (internal buffer is discarded and lost). Lexical state is set to YY_INITIAL.
        Parameters:
        reader - the new input stream

      • yystate

        public final int yystate()
        Returns the current lexical state.

      • yybegin

        public final void yybegin​(int newState)
        Enters a new lexical state
        Specified by:
        yybegin in class AbstractJFlexTokenMaker
        Parameters:
        newState - the new lexical state

      • yytext

        public final String yytext()
        Returns the text matched by the current regular expression.

      • yycharat

        public final char yycharat​(int pos)
        Returns the character at position pos from the matched text. It is equivalent to yytext().charAt(pos), but faster
        Parameters:
        pos - the position of the character to fetch. A value from 0 to yylength()-1.
        Returns:
        the character at position pos

      • yylength

        public final int yylength()
        Returns the length of the matched text region.

      • yypushback

        public void yypushback​(int number)
        Pushes the specified amount of characters back into the input stream. They will be read again by then next call of the scanning method
        Parameters:
        number - the number of characters to be read again. This number must not be greater than yylength()!

      • yylex

        public Token yylex()
            throws IOException
        Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.
        Returns:
        the next token
        Throws:
        IOException - if any I/O-Error occurs