private static class DefaultSetHolder {
/** @deprecated (3.1) remove this for Lucene 5.0 */
@Deprecated
static final CharArraySet DEFAULT_STOP_SET_30 =
CharArraySet.unmodifiableSet(
new CharArraySet(Version.LUCENE_CURRENT, Arrays.asList(RUSSIAN_STOP_WORDS_30), false));
static final CharArraySet DEFAULT_STOP_SET;
static {
try {
DEFAULT_STOP_SET =
WordlistLoader.getSnowballWordSet(
IOUtils.getDecodingReader(
SnowballFilter.class, DEFAULT_STOPWORD_FILE, IOUtils.CHARSET_UTF_8),
Version.LUCENE_CURRENT);
} catch (IOException ex) {
// default set should always be present as it is part of the
// distribution (JAR)
throw new RuntimeException("Unable to load default stopword set", ex);
}
}
}
/**
* Builds an analyzer with the given stop words and a stem exclusion set. If a stem exclusion set
* is provided this analyzer will add a {@link KeywordMarkerFilter} before {@link
* BulgarianStemFilter}.
*/
public BulgarianAnalyzer(
Version matchVersion, CharArraySet stopwords, CharArraySet stemExclusionSet) {
super(matchVersion, stopwords);
this.stemExclusionSet =
CharArraySet.unmodifiableSet(CharArraySet.copy(matchVersion, stemExclusionSet));
}
/**
* Builds an analyzer with the given stop words and a set of work to be excluded from the {@link
* CzechStemFilter}.
*
* @param matchVersion Lucene version to match
* @param stopwords a stopword set
* @param stemExclusionTable a stemming exclusion set
*/
public CzechAnalyzer(
Version matchVersion, CharArraySet stopwords, CharArraySet stemExclusionTable) {
super(matchVersion, stopwords);
this.stemExclusionTable =
CharArraySet.unmodifiableSet(CharArraySet.copy(matchVersion, stemExclusionTable));
}
/**
* Builds an analyzer with the given stop words. If a non-empty stem exclusion set is provided
* this analyzer will add a {@link KeywordMarkerFilter} before stemming.
*
* @param matchVersion lucene compatibility version
* @param stopwords a stopword set
* @param stemExclusionSet a set of terms not to be stemmed
*/
public DanishAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionSet) {
super(matchVersion, stopwords);
this.stemExclusionSet =
CharArraySet.unmodifiableSet(CharArraySet.copy(matchVersion, stemExclusionSet));
}
/**
* Builds an analyzer with the given stop words. If a non-empty stem exclusion set is provided
* this analyzer will add a {@link SetKeywordMarkerFilter} before stemming.
*
* @param stopwords a stopword set
* @param stemExclusionSet a set of terms not to be stemmed
*/
public SpanishAnalyzer(CharArraySet stopwords, CharArraySet stemExclusionSet) {
super(stopwords);
this.stemExclusionSet = CharArraySet.unmodifiableSet(CharArraySet.copy(stemExclusionSet));
}
/** {@link Analyzer} for Irish. */
public final class IrishAnalyzer extends StopwordAnalyzerBase {
private final CharArraySet stemExclusionSet;
/** File containing default Irish stopwords. */
public static final String DEFAULT_STOPWORD_FILE = "stopwords.txt";
private static final CharArraySet DEFAULT_ARTICLES =
CharArraySet.unmodifiableSet(new CharArraySet(Arrays.asList("d", "m", "b"), true));
/**
* When StandardTokenizer splits t‑athair into {t, athair}, we don't want to cause a position
* increment, otherwise there will be problems with phrase queries versus tAthair (which would not
* have a gap).
*/
private static final CharArraySet HYPHENATIONS =
CharArraySet.unmodifiableSet(new CharArraySet(Arrays.asList("h", "n", "t"), true));
/**
* Returns an unmodifiable instance of the default stop words set.
*
* @return default stop words set.
*/
public static CharArraySet getDefaultStopSet() {
return DefaultSetHolder.DEFAULT_STOP_SET;
}
/**
* Atomically loads the DEFAULT_STOP_SET in a lazy fashion once the outer class accesses the
* static final set the first time.;
*/
private static class DefaultSetHolder {
static final CharArraySet DEFAULT_STOP_SET;
static {
try {
DEFAULT_STOP_SET = loadStopwordSet(false, IrishAnalyzer.class, DEFAULT_STOPWORD_FILE, "#");
} catch (IOException ex) {
// default set should always be present as it is part of the
// distribution (JAR)
throw new RuntimeException("Unable to load default stopword set");
}
}
}
/** Builds an analyzer with the default stop words: {@link #DEFAULT_STOPWORD_FILE}. */
public IrishAnalyzer() {
this(DefaultSetHolder.DEFAULT_STOP_SET);
}
/**
* Builds an analyzer with the given stop words.
*
* @param stopwords a stopword set
*/
public IrishAnalyzer(CharArraySet stopwords) {
this(stopwords, CharArraySet.EMPTY_SET);
}
/**
* Builds an analyzer with the given stop words. If a non-empty stem exclusion set is provided
* this analyzer will add a {@link SetKeywordMarkerFilter} before stemming.
*
* @param stopwords a stopword set
* @param stemExclusionSet a set of terms not to be stemmed
*/
public IrishAnalyzer(CharArraySet stopwords, CharArraySet stemExclusionSet) {
super(stopwords);
this.stemExclusionSet = CharArraySet.unmodifiableSet(CharArraySet.copy(stemExclusionSet));
}
/**
* Creates a {@link org.apache.lucene.analysis.Analyzer.TokenStreamComponents} which tokenizes all
* the text in the provided {@link Reader}.
*
* @return A {@link org.apache.lucene.analysis.Analyzer.TokenStreamComponents} built from an
* {@link StandardTokenizer} filtered with {@link StandardFilter}, {@link
* IrishLowerCaseFilter}, {@link StopFilter} , {@link SetKeywordMarkerFilter} if a stem
* exclusion set is provided and {@link SnowballFilter}.
*/
@Override
protected TokenStreamComponents createComponents(String fieldName) {
final Tokenizer source = new StandardTokenizer();
TokenStream result = new StandardFilter(source);
result = new StopFilter(result, HYPHENATIONS);
result = new ElisionFilter(result, DEFAULT_ARTICLES);
result = new IrishLowerCaseFilter(result);
result = new StopFilter(result, stopwords);
if (!stemExclusionSet.isEmpty()) result = new SetKeywordMarkerFilter(result, stemExclusionSet);
result = new SnowballFilter(result, new IrishStemmer());
return new TokenStreamComponents(source, result);
}
}