LUCENE-8526: Add javadocs in CJKBigramFilter explaining the behavior of the StandardTokenizer on Hangul syllables.

This commit is contained in:
Jim Ferenczi 2018-10-11 13:49:14 +01:00
parent 971a0e3f4a
commit c87778c504
1 changed files with 8 additions and 0 deletions

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@ -43,6 +43,14 @@ import org.apache.lucene.util.ArrayUtil;
* flag in {@link CJKBigramFilter#CJKBigramFilter(TokenStream, int, boolean)}.
* This can be used for a combined unigram+bigram approach.
* <p>
* Unlike ICUTokenizer, StandardTokenizer does not split at script boundaries.
* Korean Hangul characters are treated the same as many other scripts'
* letters, and as a result, StandardTokenizer can produce tokens that mix
* Hangul and non-Hangul characters, e.g. "한국abc". Such mixed-script tokens
* are typed as <code>&lt;ALPHANUM&gt;</code> rather than
* <code>&lt;HANGUL&gt;</code>, and as a result, will not be converted to
* bigrams by CJKBigramFilter.
*
* In all cases, all non-CJK input is passed thru unmodified.
*/
public final class CJKBigramFilter extends TokenFilter {