net.sf.saxon.regex

Class ARegexIterator

java.lang.Object

net.sf.saxon.regex.ARegexIterator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, LastPositionFinder, SequenceIterator, RegexIterator

public class ARegexIterator
extends java.lang.Object
implements RegexIterator, LastPositionFinder

Class ARegexIterator - provides an iterator over matched and unmatched substrings. This implementation of RegexIterator uses the modified Jakarta regular expression engine.

Constructor Summary

Constructors

Constructor and Description
ARegexIterator(UnicodeString str, UnicodeString regex, REMatcher matcher) Construct a RegexIterator.

Method Summary

Modifier and Type	Method and Description
static IntToIntHashMap	computeNestingTable(UnicodeString regex) Compute a table showing for each captured group number (opening paren in the regex), the number of its parent group.
int	getLength() Get the last position (that is, the number of items in the sequence).
int	getNumberOfGroups() Get the number of captured groups
UnicodeString	getRegexGroup(int number) Get a substring that matches a parenthesised group within the regular expression
boolean	isMatching() Determine whether the current item is a matching item or a non-matching item
StringValue	next() Get the next item in the sequence
void	processMatchingSubstring(RegexMatchHandler action) Process a matching substring, performing specified actions at the start and end of each captured subgroup.
boolean	supportsGetLength() Ask whether this iterator supports use of the LastPositionFinder.getLength() method.

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.om.SequenceIterator

close, discharge

Constructor Detail

ARegexIterator

public ARegexIterator(UnicodeString str,
                      UnicodeString regex,
                      REMatcher matcher)

Construct a RegexIterator. Note that the underlying matcher.find() method is called once to obtain each matching substring. But the iterator also returns non-matching substrings if these appear between the matching substrings.

Parameters:

str - the string to be analysed

matcher - a matcher for the regular expression

Method Detail

supportsGetLength

public boolean supportsGetLength()

Description copied from interface: LastPositionFinder

Ask whether this iterator supports use of the LastPositionFinder.getLength() method. This method should always be called before calling LastPositionFinder.getLength(), because an iterator that implements this interface may support use of LastPositionFinder.getLength() in some situations and not in others

Specified by:

supportsGetLength in interface LastPositionFinder

Returns:

true if the LastPositionFinder.getLength() method can be called to determine the length of the underlying sequence.

getLength

public int getLength()

Description copied from interface: LastPositionFinder

Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The result is undefined if the next() method of the iterator has already returned null. This method must not be called unless the LastPositionFinder.supportsGetLength() has been called and has returned true.

Specified by:

getLength in interface LastPositionFinder

Returns:

the number of items in the sequence

next

public StringValue next()

Get the next item in the sequence

Specified by:

next in interface SequenceIterator

Specified by:

next in interface RegexIterator

Returns:

the next item in the sequence

isMatching

public boolean isMatching()

Determine whether the current item is a matching item or a non-matching item

Specified by:

isMatching in interface RegexIterator

Returns:

true if the current item (the one most recently returned by next()) is an item that matches the regular expression, or false if it is an item that does not match

getRegexGroup

public UnicodeString getRegexGroup(int number)

Get a substring that matches a parenthesised group within the regular expression

Specified by:

getRegexGroup in interface RegexIterator

Parameters:

number - the number of the group to be obtained

Returns:

the substring of the current item that matches the n'th parenthesized group within the regular expression

getNumberOfGroups

public int getNumberOfGroups()

Get the number of captured groups

Specified by:

getNumberOfGroups in interface RegexIterator

processMatchingSubstring

public void processMatchingSubstring(RegexMatchHandler action)
                              throws XPathException

Process a matching substring, performing specified actions at the start and end of each captured subgroup. This method will always be called when operating in "push" mode; it writes its result to context.getReceiver(). The matching substring text is all written to the receiver, interspersed with calls to the RegexMatchHandler methods onGroupStart() and onGroupEnd().

Specified by:

processMatchingSubstring in interface RegexIterator

Parameters:

action - defines the processing to be performed at the start and end of a group

Throws:

XPathException

computeNestingTable

public static IntToIntHashMap computeNestingTable(UnicodeString regex)

Compute a table showing for each captured group number (opening paren in the regex), the number of its parent group. This is done by reparsing the source of the regular expression. This is needed when the result of a match includes an empty group, to determine its position relative to other groups finishing at the same character position.