Oracle Fusion Middleware Java API Reference for Oracle Extension SDK Reference
11g Release 1 (11.1.1.6.0)

E13403-07

oracle.javatools.parser
Class AbstractLexer

java.lang.Object
  extended by oracle.javatools.parser.AbstractLexer
All Implemented Interfaces:
Lexer
Direct Known Subclasses:
CSSLexer, DefinitionLexer, DiffLexer, FastLexer, GenericLexer, HTMLLexer, PlsqlLexer, PlsqlLexer, PropertiesLexer, SqlLexer, SqlPlsqlLexer, TagLexer

public abstract class AbstractLexer
extends java.lang.Object
implements Lexer

The AbstractLexer is a basic abstract implementation which takes care of common functionality across all Lexers, such as the buffer and offset issues, and for providing a basic LexerToken object which just stores token and offset information.

See Also:
Lexer, AbstractLexer.DefaultLexerToken

Nested Class Summary
protected static class AbstractLexer.DefaultLexerToken
          The DefaultLexerToken just implements a basic LexerToken which stores a token and start/end offsets.
 
Field Summary
protected  int currentPos
          The current position in the buffer where the next lex operation will occur (assuming that backup() has not been called.)
protected  ReadTextBuffer textBuffer
          The underlying text buffer we are lexing.
 
Fields inherited from interface oracle.javatools.parser.Lexer
TK_EOF, TK_NOT_FOUND
 
Constructor Summary
AbstractLexer()
           
 
Method Summary
abstract  void backup()
          Unlexes the last found token.
 LexerToken createLexerToken()
          Creates an empty LexerToken for a specific Lexer implementation to be passed in to the lex() call to be filled in.
 ReadTextBuffer getTextBuffer()
          Gets the text buffer that is being used by this Lexer.
abstract  int lex(LexerToken lexedToken)
          Scans the text buffer at the current position and returns the token that was found.
 void setPosition(int offset)
          Sets the current lex (read) position to the given offset in the buffer.
 void setTextBuffer(ReadTextBuffer buffer)
          Sets the text buffer that is to be used by this Lexer.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

textBuffer

protected ReadTextBuffer textBuffer
The underlying text buffer we are lexing.


currentPos

protected int currentPos
The current position in the buffer where the next lex operation will occur (assuming that backup() has not been called.)

Constructor Detail

AbstractLexer

public AbstractLexer()
Method Detail

setTextBuffer

public void setTextBuffer(ReadTextBuffer buffer)
Sets the text buffer that is to be used by this Lexer.

Specified by:
setTextBuffer in interface Lexer
Parameters:
buffer - the text buffer to use

getTextBuffer

public ReadTextBuffer getTextBuffer()
Gets the text buffer that is being used by this Lexer.

Specified by:
getTextBuffer in interface Lexer
Returns:
the text buffer being used

setPosition

public void setPosition(int offset)
Sets the current lex (read) position to the given offset in the buffer. It is the clients responsibility to ensure that this offset corresponds to the start of a token, otherwise unexpected (and incorrect) results may occur.

Specified by:
setPosition in interface Lexer
Parameters:
offset - the offset for the next lex() operation.

createLexerToken

public LexerToken createLexerToken()
Creates an empty LexerToken for a specific Lexer implementation to be passed in to the lex() call to be filled in.

Specified by:
createLexerToken in interface Lexer
Returns:
a newly created LexerToken

lex

public abstract int lex(LexerToken lexedToken)
Scans the text buffer at the current position and returns the token that was found. The token and offset information is also stored in the lexedToken instance passed in to the call.

Specified by:
lex in interface Lexer
Parameters:
lexedToken - the instance passed in where token info is stored
Returns:
the token that was found, same as calling lexedToken.getToken() (for convenience)

backup

public abstract void backup()
Unlexes the last found token. The next call to lex() will return the last token and offset information found.

Specified by:
backup in interface Lexer

Oracle Fusion Middleware Java API Reference for Oracle Extension SDK Reference
11g Release 1 (11.1.1.6.0)

E13403-07

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