net.sf.saxon.regex

Class Operation.OpBackReference

java.lang.Object

net.sf.saxon.regex.Operation

net.sf.saxon.regex.Operation.OpBackReference

Enclosing class:

Operation

public static class Operation.OpBackReference
extends Operation

Back-reference

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.saxon.regex.Operation

Operation.OpAtom, Operation.OpBackReference, Operation.OpBOL, Operation.OpCapture, Operation.OpCharClass, Operation.OpChoice, Operation.OpEndProgram, Operation.OpEOL, Operation.OpGreedyFixed, Operation.OpNothing, Operation.OpReluctantFixed, Operation.OpRepeat, Operation.OpSequence, Operation.OpTrace, Operation.OpUnambiguousRepeat

Field Summary

Fields

Modifier and Type	Field and Description
int	groupNr

Fields inherited from class net.sf.saxon.regex.Operation

MATCHES_ZLS_ANYWHERE, MATCHES_ZLS_AT_END, MATCHES_ZLS_AT_START, MATCHES_ZLS_NEVER

Constructor Summary

Constructors

Constructor and Description
OpBackReference(int groupNr)

Method Summary

Modifier and Type	Method and Description
String	display() Display the operation as a regular expression, possibly in abbreviated form
IntIterator	iterateMatches(REMatcher matcher, int position) Get an iterator returning all the matches for this operation
int	matchesEmptyString() Ask whether the regular expression is known, after static analysis, to match a zero-length string

Methods inherited from class net.sf.saxon.regex.Operation

containsCapturingExpressions, getInitialCharacterClass, getMatchLength, getMinimumMatchLength, optimize

Methods inherited from class java.lang.Object

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

Field Detail

groupNr

public int groupNr

Constructor Detail

OpBackReference

public OpBackReference(int groupNr)

Method Detail

matchesEmptyString

public int matchesEmptyString()

Ask whether the regular expression is known, after static analysis, to match a zero-length string

Specified by:

matchesEmptyString in class Operation

Returns:

false. Returning true means that the expression is known statically to match ""; returning false means that this cannot be determined statically; it does not mean that the expression does not match "". We cannot do the analysis statically where back-references are involved, so we return false.

iterateMatches

public IntIterator iterateMatches(REMatcher matcher,
                                  int position)

Description copied from class: Operation

Get an iterator returning all the matches for this operation

Specified by:

iterateMatches in class Operation

Parameters:

matcher - supplies the context for the matching; may be updated with information about captured groups

position - the start position to seek a match

Returns:

an iterator returning the endpoints of all matches starting at the supplied position

display

public String display()

Display the operation as a regular expression, possibly in abbreviated form

Specified by:

display in class Operation

Returns:

the operation in a form that is recognizable as a regular expression or abbreviated regular expression