org.egothor.text
Class CharStreamBuffer

java.lang.Object
  org.egothor.text.CharStreamBuffer

All Implemented Interfaces:

CharStream

public class CharStreamBuffer
extends java.lang.Object
implements CharStream

Constructor Summary

CharStreamBuffer(java.lang.String s)

CharStreamBuffer(java.lang.StringBuilder sb, WeightReader weighter)

Method Summary

void	backup(int amount) Backs up the input stream by amount steps.
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.
int	getBeginColumn() Returns the column number of the first character for current token (being matched after the last call to BeginTOken).
int	getBeginLine() Returns the line number of the first character for current token (being matched after the last call to BeginTOken).
int	getColumn() Returns the column position of the character last read.
int	getEndColumn() Returns the column number of the last character for current token (being matched after the last call to BeginToken).
int	getEndLine() Returns the line number of the last character for current token (being matched after the last call to BeginToken).
java.lang.String	GetImage() Returns a string made up of characters from the marked token beginning to the current buffer position.
int	getLine() Returns the line number of the character last read.
WeightReader	getWeighter() Returns weights on the text, can be null, if none special weights should be applied.
char	readChar() Returns the next character from the selected input.

Methods inherited from class java.lang.Object

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

Constructor Detail

CharStreamBuffer

public CharStreamBuffer(java.lang.StringBuilder sb,
                        WeightReader weighter)

CharStreamBuffer

public CharStreamBuffer(java.lang.String s)

Method Detail

readChar

public char readChar()
              throws java.io.IOException

Returns the next character from the selected input. The method of selecting the input is the responsibility of the class implementing this interface. Can throw any java.io.IOException.

Specified by:

readChar in interface CharStream

Throws:

java.io.IOException

getColumn

public int getColumn()

Description copied from interface: CharStream

Returns the column position of the character last read.

Specified by:

getColumn in interface CharStream

See Also:

CharStream.getEndColumn()

getLine

public int getLine()

Description copied from interface: CharStream

Returns the line number of the character last read.

Specified by:

getLine in interface CharStream

See Also:

CharStream.getEndLine()

getEndColumn

public int getEndColumn()

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 int getEndLine()

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 int getBeginColumn()

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 int getBeginLine()

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 void backup(int amount)

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

BeginToken

public char BeginToken()
                throws java.io.IOException

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:

java.io.IOException

GetImage

public java.lang.String GetImage()

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

Done

public 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. 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

getWeighter

public WeightReader getWeighter()

Description copied from interface: CharStream

Returns weights on the text, can be null, if none special weights should be applied.

Specified by:

getWeighter in interface CharStream