Package com.yahoo.prelude.semantics.parser

Class AbstractCharStream

  • All Implemented Interfaces:
    CharStream
    Direct Known Subclasses:
    SimpleCharStream
    public abstract class AbstractCharStream
extends java.lang.Object
implements CharStream
    An implementation of interface CharStream, where the stream is assumed to contain only ASCII characters (without unicode processing).

    • Field Detail

      • bufpos

        protected int bufpos
        Position in buffer.

      • bufsize

        protected int bufsize

      • available

        protected int available

      • tokenBegin

        protected int tokenBegin

      • bufline

        protected int[] bufline

      • bufcolumn

        protected int[] bufcolumn

      • column

        protected int column

      • line

        protected int line

      • prevCharIsCR

        protected boolean prevCharIsCR

      • prevCharIsLF

        protected boolean prevCharIsLF

      • buffer

        protected char[] buffer

      • maxNextCharInd

        protected int maxNextCharInd

      • inBuf

        protected int inBuf

      • nextCharBuf

        protected char[] nextCharBuf

      • nextCharInd

        protected int nextCharInd

    • Constructor Detail

      • AbstractCharStream

        public AbstractCharStream​(int startline,
                          int startcolumn,
                          int buffersize)
        Constructor.

    • Method Detail

      • setTabSize

        public void setTabSize​(int i)
        Description copied from interface: CharStream
        Set the tab size to use.
        Specified by:
        setTabSize in interface CharStream
        Parameters:
        i - spaces per tab

      • getTabSize

        public int getTabSize()
        Specified by:
        getTabSize in interface CharStream
        Returns:
        Current tab size.

      • expandBuff

        protected void expandBuff​(boolean wrapAround)

      • streamRead

        protected abstract int streamRead​(char[] buf,
                                  int offset,
                                  int len)
                           throws java.io.IOException
        Throws:
        java.io.IOException

      • streamClose

        protected abstract void streamClose()
                             throws java.io.IOException
        Throws:
        java.io.IOException

      • fillBuff

        protected void fillBuff()
                 throws java.io.IOException
        Throws:
        java.io.IOException

      • beginToken

        public char beginToken()
                throws java.io.IOException
        Specified by:
        beginToken in interface CharStream
        Returns:
        the next character that marks the beginning of the next token. All characters must remain in the buffer between two successive calls to this method to implement backup correctly.
        Throws:
        java.io.IOException

      • updateLineColumn

        protected void updateLineColumn​(char c)

      • readChar

        public char readChar()
              throws java.io.IOException
        Read a character.
        Specified by:
        readChar in interface CharStream
        Returns:
        the next character from the selected input
        Throws:
        java.io.IOException - on IO error

      • getBeginColumn

        public int getBeginColumn()
        Specified by:
        getBeginColumn in interface CharStream
        Returns:
        the column number of the first character for current token (being matched after the last call to beginToken).

      • getBeginLine

        public int getBeginLine()
        Specified by:
        getBeginLine in interface CharStream
        Returns:
        the line number of the first character for current token (being matched after the last call to BeginToken).

      • getEndColumn

        public int getEndColumn()
        Specified by:
        getEndColumn in interface CharStream
        Returns:
        the column number of the last character for current token (being matched after the last call to BeginToken).

      • getEndLine

        public int getEndLine()
        Specified by:
        getEndLine in interface CharStream
        Returns:
        the line number of the last character for current token (being matched after the last call to BeginToken).

      • backup

        public void backup​(int amount)
        Description copied from interface: CharStream
        Backs up the input stream by amount steps. Lexer calls this method if it had already read some characters, but could not use them to match a (longer) token. So, they will be used again as the prefix of the next token and it is the implemetation's responsibility to do this right.
        Specified by:
        backup in interface CharStream
        Parameters:
        amount - Number of chars to back up.

      • reInit

        public void reInit​(int startline,
                   int startcolumn,
                   int buffersize)
        Reinitialise.

      • getImage

        public java.lang.String getImage()
        Specified by:
        getImage in interface CharStream
        Returns:
        a string made up of characters from the marked token beginning to the current buffer position. Implementations have the choice of returning anything that they want to. For example, for efficiency, one might decide to just return null, which is a valid implementation.

      • getSuffix

        public char[] getSuffix​(int len)
        Specified by:
        getSuffix in interface CharStream
        Returns:
        an array of characters that make up the suffix of length 'len' for the currently matched token. This is used to build up the matched string for use in actions in the case of MORE. A simple and inefficient implementation of this is as follows: 
           {
      String t = getImage();
      return t.substring(t.length() - len, t.length()).toCharArray();
   }

      • done

        public void done()
        Description copied from interface: CharStream
        The lexer calls this function to indicate that it is done with the stream and hence implementations can free any resources held by this class. Again, the body of this function can be just empty and it will not affect the lexer's operation.
        Specified by:
        done in interface CharStream

      • adjustBeginLineColumn

        public void adjustBeginLineColumn​(int nNewLine,
                                  int newCol)
        Method to adjust line and column numbers for the start of a token.

      • setTrackLineColumn

        public void setTrackLineColumn​(boolean tlc)
        Description copied from interface: CharStream
        Enable or disable line number and column number tracking.
        Specified by:
        setTrackLineColumn in interface CharStream
        Parameters:
        tlc - true to track it, false to not do it.

      • isTrackLineColumn

        public boolean isTrackLineColumn()
        Specified by:
        isTrackLineColumn in interface CharStream
        Returns:
        true if line number and column numbers should be tracked.