| package org.apache.lucene.analysis.standard; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| import org.apache.lucene.analysis.TokenStream; |
| 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.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; |
| |
| /** |
| * Filters {@link StandardTokenizer} with {@link StandardFilter}, {@link |
| * LowerCaseFilter} and {@link StopFilter}, using a list of |
| * English stop words. |
| * |
| * <a name="version"/> |
| * <p>You may specify the {@link Version} |
| * compatibility when creating StandardAnalyzer: |
| * <ul> |
| * <li> As of 3.4, Hiragana and Han characters are no longer wrongly split |
| * from their combining characters. If you use a previous version number, |
| * you get the exact broken behavior for backwards compatibility. |
| * <li> As of 3.1, StandardTokenizer implements Unicode text segmentation, |
| * and StopFilter correctly handles Unicode 4.0 supplementary characters |
| * in stopwords. {@link ClassicTokenizer} and {@link ClassicAnalyzer} |
| * are the pre-3.1 implementations of StandardTokenizer and |
| * StandardAnalyzer. |
| * </ul> |
| */ |
| public final class StandardAnalyzer extends StopwordAnalyzerBase { |
| |
| /** Default maximum allowed token length */ |
| public static final int DEFAULT_MAX_TOKEN_LENGTH = 255; |
| |
| private int maxTokenLength = DEFAULT_MAX_TOKEN_LENGTH; |
| |
| /** 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 stopWords stop words */ |
| public StandardAnalyzer(CharArraySet stopWords) { |
| super(stopWords); |
| } |
| |
| /** |
| * @deprecated Use {@link #StandardAnalyzer(CharArraySet)} |
| */ |
| @Deprecated |
| public StandardAnalyzer(Version matchVersion, CharArraySet stopWords) { |
| super(matchVersion, stopWords); |
| } |
| |
| /** Builds an analyzer with the default stop words ({@link #STOP_WORDS_SET}). |
| */ |
| public StandardAnalyzer() { |
| this(STOP_WORDS_SET); |
| } |
| |
| /** |
| * @deprecated Use {@link #StandardAnalyzer()} |
| */ |
| @Deprecated |
| public StandardAnalyzer(Version matchVersion) { |
| this(matchVersion, STOP_WORDS_SET); |
| } |
| |
| /** Builds an analyzer with the stop words from the given reader. |
| * @see WordlistLoader#getWordSet(Reader) |
| * @param stopwords Reader to read stop words from */ |
| public StandardAnalyzer(Reader stopwords) throws IOException { |
| this(loadStopwordSet(stopwords)); |
| } |
| |
| /** |
| * @deprecated Use {@link #StandardAnalyzer()} |
| */ |
| @Deprecated |
| public StandardAnalyzer(Version matchVersion, Reader stopwords) throws IOException { |
| this(matchVersion, loadStopwordSet(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 |
| * tokenStream 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(getVersion(), reader); |
| src.setMaxTokenLength(maxTokenLength); |
| TokenStream tok = new StandardFilter(getVersion(), src); |
| tok = new LowerCaseFilter(getVersion(), tok); |
| tok = new StopFilter(getVersion(), tok, stopwords); |
| return new TokenStreamComponents(src, tok) { |
| @Override |
| protected void setReader(final Reader reader) throws IOException { |
| src.setMaxTokenLength(StandardAnalyzer.this.maxTokenLength); |
| super.setReader(reader); |
| } |
| }; |
| } |
| } |