org.apache.lucene.analysis.icu.segmentation
Class LaoBreakIterator

java.lang.Object
  com.ibm.icu.text.BreakIterator
      org.apache.lucene.analysis.icu.segmentation.LaoBreakIterator

All Implemented Interfaces:

Cloneable

public class LaoBreakIterator
extends com.ibm.icu.text.BreakIterator

Syllable iterator for Lao text.

This breaks Lao text into syllables according to: Syllabification of Lao Script for Line Breaking Phonpasit Phissamay, Valaxay Dalolay, Chitaphone Chanhsililath, Oulaiphone Silimasak, Sarmad Hussain, Nadir Durrani, Science Technology and Environment Agency, CRULP.

• http://www.panl10n.net/english/final%20reports/pdf%20files/Laos/LAO06.pdf
• http://www.panl10n.net/Presentations/Cambodia/Phonpassit/LineBreakingAlgo.pdf

Most work is accomplished with RBBI rules, however some additional special logic is needed that cannot be coded in a grammar, and this is implemented here.

For example, what appears to be a final consonant might instead be part of the next syllable. Rules match in a greedy fashion, leaving an illegal sequence that matches no rules.

Take for instance the text ກວ່າດອກ The first rule greedily matches ກວ່າດ, but then ອກ is encountered, which is illegal. What LaoBreakIterator does, according to the paper:

1. backtrack and remove the ດ from the last syllable, placing it on the current syllable.
2. verify the modified previous syllable (ກວ່າ ) is still legal.
3. verify the modified current syllable (ດອກ) is now legal.
4. If 2 or 3 fails, then restore the ດ to the last syllable and skip the current character.

Finally, LaoBreakIterator also takes care of the second concern mentioned in the paper. This is the issue of combining marks being in the wrong order (typos).

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields inherited from class com.ibm.icu.text.BreakIterator

DONE, KIND_CHARACTER, KIND_LINE, KIND_SENTENCE, KIND_TITLE, KIND_WORD

Constructor Summary

LaoBreakIterator(com.ibm.icu.text.RuleBasedBreakIterator rules)
Creates a new iterator, performing the backtracking verification across the provided rules.

Method Summary

LaoBreakIterator	clone() Clone method.
int	current()
int	first()
int	following(int offset)
CharacterIterator	getText()
int	last()
int	next()
int	next(int n)
int	previous()
void	setText(CharacterIterator text)
void	setText(String newText)

Methods inherited from class com.ibm.icu.text.BreakIterator

getAvailableLocales, getAvailableULocales, getBreakInstance, getCharacterInstance, getCharacterInstance, getCharacterInstance, getLineInstance, getLineInstance, getLineInstance, getLocale, getSentenceInstance, getSentenceInstance, getSentenceInstance, getTitleInstance, getTitleInstance, getTitleInstance, getWordInstance, getWordInstance, getWordInstance, isBoundary, preceding, registerInstance, registerInstance, unregister

Methods inherited from class java.lang.Object

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

Constructor Detail

LaoBreakIterator

public LaoBreakIterator(com.ibm.icu.text.RuleBasedBreakIterator rules)

Creates a new iterator, performing the backtracking verification across the provided rules.

Method Detail

current

public int current()

Specified by:

current in class com.ibm.icu.text.BreakIterator

first

public int first()

Specified by:

first in class com.ibm.icu.text.BreakIterator

following

public int following(int offset)

Specified by:

following in class com.ibm.icu.text.BreakIterator

getText

public CharacterIterator getText()

Specified by:

getText in class com.ibm.icu.text.BreakIterator

last

public int last()

Specified by:

last in class com.ibm.icu.text.BreakIterator

next

public int next()

Specified by:

next in class com.ibm.icu.text.BreakIterator

next

public int next(int n)

Specified by:

next in class com.ibm.icu.text.BreakIterator

previous

public int previous()

Specified by:

previous in class com.ibm.icu.text.BreakIterator

setText

public void setText(CharacterIterator text)

Specified by:

setText in class com.ibm.icu.text.BreakIterator

setText

public void setText(String newText)

Overrides:

setText in class com.ibm.icu.text.BreakIterator

clone

public LaoBreakIterator clone()

Clone method. Creates another LaoBreakIterator with the same behavior and current state as this one.

Overrides:

clone in class com.ibm.icu.text.BreakIterator

Returns:

The clone.