net.sf.saxon.regex

Class ARegexIterator

java.lang.Object

net.sf.saxon.regex.ARegexIterator

All Implemented Interfaces:

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.

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.saxon.regex.RegexIterator

RegexIterator.MatchHandler

Field Summary

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

ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
void	close() Close the iterator.
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
int	getProperties() Get properties of this iterator, as a bit-significant integer.
java.lang.String	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
Item	next() Get the next item in the sequence
void	processMatchingSubstring(RegexIterator.MatchHandler action) Process a matching substring, performing specified actions at the start and end of each captured subgroup.

Methods inherited from class java.lang.Object

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

Constructor Detail

ARegexIterator

public ARegexIterator(UnicodeString string,
                      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:

string - the string to be analysed

matcher - a matcher for the regular expression

Method Detail

getLength

public int getLength()
              throws XPathException

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 result of getProperties() on the iterator includes the bit setting SequenceIterator.LAST_POSITION_FINDER

Specified by:

getLength in interface LastPositionFinder

Returns:

the number of items in the sequence

Throws:

XPathException - if an error occurs evaluating the sequence in order to determine the number of items

next

public Item next()
          throws XPathException

Get the next item in the sequence

Specified by:

next in interface SequenceIterator

Returns:

the next item in the sequence

Throws:

XPathException - if an error occurs retrieving the next item

close

public void close()

Description copied from interface: SequenceIterator

Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

(Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

Specified by:

close in interface SequenceIterator

getProperties

public int getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator

Returns:

the properties of this iterator. This will be some combination of properties such as SequenceIterator.GROUNDED, SequenceIterator.LAST_POSITION_FINDER, and SequenceIterator.LOOKAHEAD. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.

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 java.lang.String 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(RegexIterator.MatchHandler 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 RegexIterator.MatchHandler 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.