org.eclipse.jface.text.rules

Class RuleBasedScanner

java.lang.Object

org.eclipse.jface.text.rules.RuleBasedScanner

All Implemented Interfaces:

ICharacterScanner, ITokenScanner

Direct Known Subclasses:

BufferedRuleBasedScanner

public class RuleBasedScanner
extends java.lang.Object
implements ICharacterScanner, ITokenScanner

A generic scanner which can be "programmed" with a sequence of rules. The scanner is used to get the next token by evaluating its rule in sequence until one is successful. If a rule returns a token which is undefined, the scanner will proceed to the next rule. Otherwise the token provided by the rule will be returned by the scanner. If no rule returned a defined token, this scanner returns a token which returns true when calling isOther, unless the end of the file is reached. In this case the token returns true when calling isEOF.

See Also:

IRule

Field Summary

Fields

Modifier and Type	Field and Description
protected int	fColumn The cached column of the current scanner position
protected IToken	fDefaultReturnToken The token to be returned by default if no rule fires
protected char[][]	fDelimiters The cached legal line delimiters of the document
protected IDocument	fDocument The document to be scanned
protected int	fOffset The offset of the next character to be read
protected int	fRangeEnd The end offset of the range to be scanned
protected IRule[]	fRules The list of rules of this scanner
protected int	fTokenOffset The offset of the last read token
protected static int	UNDEFINED Internal setting for the un-initialized column cache.

Fields inherited from interface org.eclipse.jface.text.rules.ICharacterScanner

EOF

Constructor Summary

Constructors

Constructor and Description
RuleBasedScanner() Creates a new rule based scanner which does not have any rule.

Method Summary

Modifier and Type	Method and Description
int	getColumn() Returns the column of the character scanner.
char[][]	getLegalLineDelimiters() Provides rules access to the legal line delimiters.
int	getTokenLength() Returns the length of the last token read by this scanner.
int	getTokenOffset() Returns the offset of the last token read by this scanner.
IToken	nextToken() Returns the next token in the document.
int	read() Returns the next character or EOF if end of file has been reached
void	setDefaultReturnToken(IToken defaultReturnToken) Configures the scanner's default return token.
void	setRange(IDocument document, int offset, int length) Configures the scanner by providing access to the document range that should be scanned.
void	setRules(IRule[] rules) Configures the scanner with the given sequence of rules.
void	unread() Rewinds the scanner before the last read character.

Methods inherited from class java.lang.Object

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

Field Detail

fRules

protected IRule[] fRules

The list of rules of this scanner

fDefaultReturnToken

protected IToken fDefaultReturnToken

The token to be returned by default if no rule fires

fDocument

protected IDocument fDocument

The document to be scanned

fDelimiters

protected char[][] fDelimiters

The cached legal line delimiters of the document

fOffset

protected int fOffset

The offset of the next character to be read

fRangeEnd

protected int fRangeEnd

The end offset of the range to be scanned

fTokenOffset

protected int fTokenOffset

The offset of the last read token

fColumn

protected int fColumn

The cached column of the current scanner position

UNDEFINED

protected static final int UNDEFINED

Internal setting for the un-initialized column cache.

See Also:

Constant Field Values

Constructor Detail

RuleBasedScanner

public RuleBasedScanner()

Creates a new rule based scanner which does not have any rule.

Method Detail

setRules

public void setRules(IRule[] rules)

Configures the scanner with the given sequence of rules.

Parameters:

rules - the sequence of rules controlling this scanner

setDefaultReturnToken

public void setDefaultReturnToken(IToken defaultReturnToken)

Configures the scanner's default return token. This is the token which is returned when none of the rules fired and EOF has not been reached.

Parameters:

defaultReturnToken - the default return token

Since:

2.0

setRange

public void setRange(IDocument document,
                     int offset,
                     int length)

Description copied from interface: ITokenScanner

Configures the scanner by providing access to the document range that should be scanned.

Specified by:

setRange in interface ITokenScanner

Parameters:

document - the document to scan

offset - the offset of the document range to scan

length - the length of the document range to scan

getTokenOffset

public int getTokenOffset()

Description copied from interface: ITokenScanner

Returns the offset of the last token read by this scanner.

Specified by:

getTokenOffset in interface ITokenScanner

Returns:

the offset of the last token read by this scanner

getTokenLength

public int getTokenLength()

Description copied from interface: ITokenScanner

Returns the length of the last token read by this scanner.

Specified by:

getTokenLength in interface ITokenScanner

Returns:

the length of the last token read by this scanner

getColumn

public int getColumn()

Description copied from interface: ICharacterScanner

Returns the column of the character scanner.

Specified by:

getColumn in interface ICharacterScanner

Returns:

the column of the character scanner

getLegalLineDelimiters

public char[][] getLegalLineDelimiters()

Description copied from interface: ICharacterScanner

Provides rules access to the legal line delimiters. The returned object may not be modified by clients.

Specified by:

getLegalLineDelimiters in interface ICharacterScanner

Returns:

the legal line delimiters

nextToken

public IToken nextToken()

Description copied from interface: ITokenScanner

Returns the next token in the document.

Specified by:

nextToken in interface ITokenScanner

Returns:

the next token in the document

read

public int read()

Description copied from interface: ICharacterScanner

Returns the next character or EOF if end of file has been reached

Specified by:

read in interface ICharacterScanner

Returns:

the next character or EOF

unread

public void unread()

Description copied from interface: ICharacterScanner

Rewinds the scanner before the last read character.

Specified by:

unread in interface ICharacterScanner