Package org.apache.lucene.search.uhighlight

Class BoundedBreakIteratorScanner

java.lang.Object

java.text.BreakIterator

org.apache.lucene.search.uhighlight.BoundedBreakIteratorScanner

All Implemented Interfaces:

Cloneable

public class BoundedBreakIteratorScanner
extends BreakIterator

A custom break iterator that is used to find break-delimited passages bounded by a provided maximum length in the UnifiedHighlighter context. This class uses a BreakIterator to find the last break after the provided offset that would create a passage smaller than maxLen. If the BreakIterator cannot find a passage smaller than the maximum length, a secondary break iterator is used to re-split the passage at the first boundary after maximum length. This is useful to split passages created by BreakIterators like `sentence` that can create big outliers on semi-structured text. WARNING: This break iterator is designed to work with the UnifiedHighlighter. TODO: We should be able to create passages incrementally, starting from the offset of the first match and expanding or not depending on the offsets of subsequent matches. This is currently impossible because FieldHighlighter uses only the first matching offset to derive the start and end of each passage.

Field Summary

Fields inherited from class java.text.BreakIterator

DONE

Method Summary

Modifier and Type	Method	Description
int	current()
int	first()
int	following(int offset)	Can be invoked only after a call to preceding(offset+1).
static BreakIterator	getSentence(Locale locale, int maxLen)	Returns a BreakIterator.getSentenceInstance(Locale) bounded to maxLen.
CharacterIterator	getText()
int	last()
int	next()
int	next(int n)
int	preceding(int offset)	Must be called with increasing offset.
int	previous()
void	setText(String newText)
void	setText(CharacterIterator newText)

Methods inherited from class java.text.BreakIterator

clone, getAvailableLocales, getCharacterInstance, getCharacterInstance, getLineInstance, getLineInstance, getSentenceInstance, getSentenceInstance, getWordInstance, getWordInstance, isBoundary

Methods inherited from class java.lang.Object

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

Method Detail

getText

public CharacterIterator getText()

Specified by:

getText in class BreakIterator

setText

public void setText(CharacterIterator newText)

Specified by:

setText in class BreakIterator

setText

public void setText(String newText)

Overrides:

setText in class BreakIterator

preceding

public int preceding(int offset)

Must be called with increasing offset. See FieldHighlighter for usage.

Overrides:

preceding in class BreakIterator

following

public int following(int offset)

Can be invoked only after a call to preceding(offset+1). See FieldHighlighter for usage.

Specified by:

following in class BreakIterator

getSentence

public static BreakIterator getSentence(Locale locale,
                                        int maxLen)

Returns a BreakIterator.getSentenceInstance(Locale) bounded to maxLen. Secondary boundaries are found using a BreakIterator.getWordInstance(Locale).

current

public int current()

Specified by:

current in class BreakIterator

first

public int first()

Specified by:

first in class BreakIterator

next

public int next()

Specified by:

next in class BreakIterator

last

public int last()

Specified by:

last in class BreakIterator

next

public int next(int n)

Specified by:

next in class BreakIterator

previous

public int previous()

Specified by:

previous in class BreakIterator