Class InputCharStream

java.lang.Object
org.exolab.castor.xml.dtd.parser.InputCharStream
All Implemented Interfaces:
CharStream
public final class InputCharStream extends Object implements CharStream
An implementation of interface CharStream. Implements input character stream that maintains line and column number positions of the characters. It also has the capability to backup the stream to some extent.
The object of this class is constructed using java.io.Reader reader and it is left to constructor of the reader to set up character encoding correctly. This means that method read of the reader is used to get next characters, assuming it returns appropriate values. It is recommended to use class java.io.InputStreamReader as a reader, which allows to set desired character encoding. This class is an intermediate component between input character reader and the parser.
The code of this class is based on the class ASCII_CharStream - implementation of interface CharStream, that JavaCC would have generated with the following options set in a JavaCC grammar file: 
    JAVA_UNICODE_ESCAPE = false;
    UNICODE_INPUT = false;
    USER_CHAR_STREAM = false;
Note that this class is not fully JavaCC generated.
Version:
$Revision: 5962 $ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $
Author:
JavaCC, Alexander Totok

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    int
    bufpos
     
    static final boolean
    staticFlag
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    InputCharStream(Reader dstream)
    Constructor, instantiating the char stream to begin at 1-st line and 1-st column of dstream.
    InputCharStream(Reader dstream, int startline, int startcolumn)
    Constructor, allowing to specify start line and start column of the char stream.
    InputCharStream(Reader dstream, int startline, int startcolumn, int buffersize)
    Constructor, allowing to specify start line and start column of the char stream, and buffer size as well.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    adjustBeginLineColumn(int newLine, int newCol)
    Method to adjust line and column numbers for the start of a token.
    final void
    backup(int amount)
    Backs up the input stream by amount steps.
    final char
    BeginToken()
    Returns the next character that marks the beginning of the next token.
    void
    Done()
    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.
    final int
    getBeginColumn()
    Returns the column number of the first character for current token (being matched after the last call to BeginTOken).
    final int
    getBeginLine()
    Returns the line number of the first character for current token (being matched after the last call to BeginTOken).
    final int
    getColumn()
    Deprecated. 
    final int
    getEndColumn()
    Returns the column number of the last character for current token (being matched after the last call to BeginTOken).
    final int
    getEndLine()
    Returns the line number of the last character for current token (being matched after the last call to BeginTOken).
    final String
    GetImage()
    Returns a string made up of characters from the marked token beginning to the current buffer position.
    final int
    getLine()
    Deprecated. 
    final char[]
    GetSuffix(int len)
    Returns an array of characters that make up the suffix of length 'len' for the currently matched token.
    final char
    readChar()
    Returns the next character from the input stream.
    void
    ReInit(Reader dstream)
    Reinitialization of the char stream, instantiating the char stream to begin at 1-st line and 1-st column of dstream.
    void
    ReInit(Reader dstream, int startline, int startcolumn)
    Reinitialization of the char stream, allowing to specify start line and start column of the char stream.
    void
    ReInit(Reader dstream, int startline, int startcolumn, int buffersize)
    Reinitialization of the char stream, allowing to specify start line and start column of the char stream, and buffer size as well.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • staticFlag

      public static final boolean staticFlag
      See Also:

    • bufpos

      public int bufpos

  • Constructor Details

    • InputCharStream

      public InputCharStream(Reader dstream, int startline, int startcolumn, int buffersize)
      Constructor, allowing to specify start line and start column of the char stream, and buffer size as well.

    • InputCharStream

      public InputCharStream(Reader dstream, int startline, int startcolumn)
      Constructor, allowing to specify start line and start column of the char stream.

    • InputCharStream

      public InputCharStream(Reader dstream)
      Constructor, instantiating the char stream to begin at 1-st line and 1-st column of dstream.

  • Method Details

    • BeginToken

      public final char BeginToken() throws IOException
      Description copied from 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.
      Specified by:
      BeginToken in interface CharStream
      Throws:
      IOException

    • readChar

      public final char readChar() throws IOException
      Returns the next character from the input stream. The only method whose implementation is different from its original in the ASCII_CharStream class.
      Specified by:
      readChar in interface CharStream
      Throws:
      IOException

    • getColumn

      public final int getColumn()
      Deprecated.
      Description copied from interface: CharStream
      Returns the column position of the character last read.
      Specified by:
      getColumn in interface CharStream
      See Also:

    • getLine

      public final int getLine()
      Deprecated.
      Description copied from interface: CharStream
      Returns the line number of the character last read.
      Specified by:
      getLine in interface CharStream
      See Also:

    • getEndColumn

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

    • getEndLine

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

    • getBeginColumn

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

    • getBeginLine

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

    • backup

      public final 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

    • ReInit

      public void ReInit(Reader dstream, int startline, int startcolumn, int buffersize)
      Reinitialization of the char stream, allowing to specify start line and start column of the char stream, and buffer size as well.

    • ReInit

      public void ReInit(Reader dstream, int startline, int startcolumn)
      Reinitialization of the char stream, allowing to specify start line and start column of the char stream.

    • ReInit

      public void ReInit(Reader dstream)
      Reinitialization of the char stream, instantiating the char stream to begin at 1-st line and 1-st column of dstream.

    • GetImage

      public final String GetImage()
      Description copied from 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.
      Specified by:
      GetImage in interface CharStream

    • GetSuffix

      public final char[] GetSuffix(int len)
      Description copied from 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();
   }
      Specified by:
      GetSuffix in interface CharStream

    • 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 newLine, int newCol)
      Method to adjust line and column numbers for the start of a token.