package org.exist.indexing.lucene.analyzers;
import org.apache.lucene.analysis.*;
import org.apache.lucene.analysis.core.LowerCaseFilter;
import org.apache.lucene.analysis.core.StopAnalyzer;
import org.apache.lucene.analysis.core.StopFilter;
import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import org.apache.lucene.analysis.util.CharArraySet;
import org.apache.lucene.analysis.util.StopwordAnalyzerBase;
import org.apache.lucene.analysis.util.WordlistLoader;
import org.apache.lucene.util.Version;
import java.io.IOException;
import java.io.Reader;
/**
* A copy of StandardAnalyzer using an additional ASCIIFoldingFilter to
* strip diacritics.
*/
public class NoDiacriticsStandardAnalyzer extends StopwordAnalyzerBase {
/** Default maximum allowed token length */
public static final int DEFAULT_MAX_TOKEN_LENGTH = 255;
private int maxTokenLength = DEFAULT_MAX_TOKEN_LENGTH;
/**
* Specifies whether deprecated acronyms should be replaced with HOST type.
* See {@linkplain "https://issues.apache.org/jira/browse/LUCENE-1068"}
*/
private final boolean replaceInvalidAcronym;
/** An unmodifiable set containing some common English words that are usually not
useful for searching. */
public static final CharArraySet STOP_WORDS_SET = StopAnalyzer.ENGLISH_STOP_WORDS_SET;
/** Builds an analyzer with the given stop words.
* @param matchVersion Lucene version to match See {@link
* <a href="#version">above</a>}
* @param stopWords stop words */
public NoDiacriticsStandardAnalyzer(Version matchVersion, CharArraySet stopWords) {
super(matchVersion, stopWords);
replaceInvalidAcronym = matchVersion.onOrAfter(Version.LUCENE_43);
}
/** Builds an analyzer with the default stop words ({@link
* #STOP_WORDS_SET}).
* @param matchVersion Lucene version to match See {@link
* <a href="#version">above</a>}
*/
public NoDiacriticsStandardAnalyzer(Version matchVersion) {
this(matchVersion, STOP_WORDS_SET);
}
/** Builds an analyzer with the stop words from the given reader.
* @see WordlistLoader#getWordSet(Reader, Version)
* @param matchVersion Lucene version to match See {@link
* <a href="#version">above</a>}
* @param stopwords Reader to read stop words from */
public NoDiacriticsStandardAnalyzer(Version matchVersion, Reader stopwords) throws IOException {
this(matchVersion, WordlistLoader.getWordSet(stopwords, matchVersion));
}
/**
* Set maximum allowed token length. If a token is seen
* that exceeds this length then it is discarded. This
* setting only takes effect the next time tokenStream or
* reusableTokenStream is called.
*/
public void setMaxTokenLength(int length) {
maxTokenLength = length;
}
/**
* @see #setMaxTokenLength
*/
public int getMaxTokenLength() {
return maxTokenLength;
}
@Override
protected TokenStreamComponents createComponents(final String fieldName, final Reader reader) {
final StandardTokenizer src = new StandardTokenizer(matchVersion, reader);
src.setMaxTokenLength(maxTokenLength);
// src.setReplaceInvalidAcronym(replaceInvalidAcronym);
TokenStream tok = new StandardFilter(matchVersion, src);
tok = new ASCIIFoldingFilter(tok);
tok = new LowerCaseFilter(matchVersion, tok);
tok = new StopFilter(matchVersion, tok, stopwords);
return new TokenStreamComponents(src, tok);
// {
// @Override
// protected boolean reset(final Reader reader) throws IOException {
// src.setMaxTokenLength(NoDiacriticsStandardAnalyzer.this.maxTokenLength);
// return super.reset(reader);
// }
// };
}
}