org.eclipse.jface.text.rules
Class PatternRule

java.lang.Object
  |
  +--org.eclipse.jface.text.rules.PatternRule

All Implemented Interfaces:

IPredicateRule, IRule

Direct Known Subclasses:

MultiLineRule, SingleLineRule

public class PatternRule

extends Object

implements IPredicateRule

Standard implementation of IPredicateRule. Is is capable of detecting a pattern which begins with a given start sequence and ends with a given end sequence. If the end sequence is not specified, it can be either end of line, end or file, or both. Additionally, the pattern can be constrained to begin in a certain column. The rule can also be used to check whether the text to scan covers half of the pattern, i.e. contains the end sequence required by the rule.

Field Summary

protected boolean	fBreaksOnEOL Indicates whether end of line termines the pattern
protected int	fColumn The pattern's column constrain
protected char[]	fEndSequence The pattern's end sequence
protected char	fEscapeCharacter The pattern's escape character
protected char[]	fStartSequence The pattern's start sequence
protected IToken	fToken The token to be returned on success
protected static int	UNDEFINED

Constructor Summary

PatternRule(String startSequence, String endSequence, IToken token, char escapeCharacter, boolean breaksOnEOL)
Creates a rule for the given starting and ending sequence.

Method Summary

protected IToken	doEvaluate(ICharacterScanner scanner) Evaluates this rules without considering any column constraints.
protected IToken	doEvaluate(ICharacterScanner scanner, boolean resume) Evaluates this rules without considering any column constraints.
protected boolean	endSequenceDetected(ICharacterScanner scanner) Returns whether the end sequence was detected.
IToken	evaluate(ICharacterScanner scanner) Evaluates the rule by examining the characters available from the provided character scanner.
IToken	evaluate(ICharacterScanner scanner, boolean resume) Evaluates the rule by examining the characters available from the provided character scanner.
IToken	getSuccessToken() Returns the success token of this predicate rule.
protected boolean	sequenceDetected(ICharacterScanner scanner, char[] sequence, boolean eofAllowed) Returns whether the next characters to be read by the character scanner are an exact match with the given sequence.
void	setColumnConstraint(int column) Sets a column constraint for this rule.

Methods inherited from class java.lang.Object

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

Field Detail

UNDEFINED

protected static final int UNDEFINED

See Also:

Constant Field Values

fToken

protected IToken fToken

The token to be returned on success

fStartSequence

protected char[] fStartSequence

The pattern's start sequence

fEndSequence

protected char[] fEndSequence

The pattern's end sequence

fColumn

protected int fColumn

The pattern's column constrain

fEscapeCharacter

protected char fEscapeCharacter

The pattern's escape character

fBreaksOnEOL

protected boolean fBreaksOnEOL

Indicates whether end of line termines the pattern

Constructor Detail

PatternRule

public PatternRule(String startSequence,
                   String endSequence,
                   IToken token,
                   char escapeCharacter,
                   boolean breaksOnEOL)

Creates a rule for the given starting and ending sequence. When these sequences are detected the rule will return the specified token. Alternatively, the sequence can also be ended by the end of the line. Any character which follows the given escapeCharacter will be ignored.

Parameters:

startSequence - the pattern's start sequence

endSequence - the pattern's end sequence, null is a legal value

token - the token which will be returned on success

escapeCharacter - any character following this one will be ignored

Method Detail

setColumnConstraint

public void setColumnConstraint(int column)

Sets a column constraint for this rule. If set, the rule's token will only be returned if the pattern is detected starting at the specified column. If the column is smaller then 0, the column constraint is considered removed.

Parameters:

column - the column in which the pattern starts

doEvaluate

protected IToken doEvaluate(ICharacterScanner scanner)

Evaluates this rules without considering any column constraints.

Parameters:

scanner - the character scanner to be used

Returns:

the token resulting from this evaluation

doEvaluate

protected IToken doEvaluate(ICharacterScanner scanner,
                            boolean resume)

Evaluates this rules without considering any column constraints. Resumes detection, i.e. look sonly for the end sequence required by this rule if the resume flag is set.

Parameters:

scanner - the character scanner to be used

resume - true if detection should be resumed, false otherwise

Returns:

the token resulting from this evaluation

Since:

2.0

evaluate

public IToken evaluate(ICharacterScanner scanner)

Description copied from interface: IRule

Evaluates the rule by examining the characters available from the provided character scanner. The token returned by this rule returns true when calling isUndefined, if the text the rule investigated does not match the rule's requirements.

Specified by:

evaluate in interface IRule

Parameters:

scanner - the character scanner to be used by this rule

Returns:

the token computed by the rule

endSequenceDetected

protected boolean endSequenceDetected(ICharacterScanner scanner)

Returns whether the end sequence was detected. As the pattern can be considered ended by a line delimiter, the result of this method is true if the rule breaks on the end of the line, or if the EOF character is read.

Parameters:

scanner - the character scanner to be used

Returns:

true if the end sequence has been detected

sequenceDetected

protected boolean sequenceDetected(ICharacterScanner scanner,
                                   char[] sequence,
                                   boolean eofAllowed)

Returns whether the next characters to be read by the character scanner are an exact match with the given sequence. No escape characters are allowed within the sequence. If specified the sequence is considered to be found when reading the EOF character.

Parameters:

scanner - the character scanner to be used

sequence - the sequence to be detected

eofAllowed - indicated whether EOF terminates the pattern

Returns:

true if the given sequence has been detected

evaluate

public IToken evaluate(ICharacterScanner scanner,
                       boolean resume)

Description copied from interface: IPredicateRule

Evaluates the rule by examining the characters available from the provided character scanner. The token returned by this rule returns true when calling isUndefined, if the text the rule investigated does not match the rule's requirements. Otherwise, this method returns this rule's success token. If this rules relies on a text pattern comprising a opening and a closing character sequence this method can also be called when the scanner is positioned already between the opening and the closing sequence. In this case, resume must be set to true.

Specified by:

evaluate in interface IPredicateRule

Parameters:

scanner - the character scanner to be used by this rule

resume - indicates that the rule starts working between the opening and the closing character sequence

Returns:

the token computed by the rule

getSuccessToken

public IToken getSuccessToken()

Description copied from interface: IPredicateRule

Returns the success token of this predicate rule.

Specified by:

getSuccessToken in interface IPredicateRule

Returns:

the success token of this rule