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package org.apache.lucene.analysis.compound;
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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import java.io.IOException;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.LinkedList;
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import java.util.Locale;
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import org.apache.lucene.analysis.CharArraySet;
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import org.apache.lucene.analysis.TokenFilter;
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import org.apache.lucene.analysis.TokenStream;
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import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
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import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
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import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
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import org.apache.lucene.util.AttributeSource;
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import org.apache.lucene.util.Version;
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* Base class for decomposition token filters.
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* You must specify the required {@link Version} compatibility when creating
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* CompoundWordTokenFilterBase:
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* <li>As of 3.1, CompoundWordTokenFilterBase correctly handles Unicode 4.0
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* supplementary characters in strings and char arrays provided as compound word
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* <p>If you pass in a {@link org.apache.lucene.analysis.CharArraySet} as dictionary,
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* it should be case-insensitive unless it contains only lowercased entries and you
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* have {@link org.apache.lucene.analysis.LowerCaseFilter} before this filter in your analysis chain.
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* For optional performance (as this filter does lots of lookups to the dictionary,
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* you should use the latter analysis chain/CharArraySet). Be aware: If you supply arbitrary
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* {@link Set Sets} to the ctors or {@code String[]} dictionaries, they will be automatically
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* transformed to case-insensitive!
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public abstract class CompoundWordTokenFilterBase extends TokenFilter {
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* The default for minimal word length that gets decomposed
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public static final int DEFAULT_MIN_WORD_SIZE = 5;
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* The default for minimal length of subwords that get propagated to the output of this filter
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public static final int DEFAULT_MIN_SUBWORD_SIZE = 2;
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* The default for maximal length of subwords that get propagated to the output of this filter
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public static final int DEFAULT_MAX_SUBWORD_SIZE = 15;
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protected final CharArraySet dictionary;
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protected final LinkedList<CompoundToken> tokens;
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protected final int minWordSize;
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protected final int minSubwordSize;
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protected final int maxSubwordSize;
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protected final boolean onlyLongestMatch;
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protected final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
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protected final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
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private final PositionIncrementAttribute posIncAtt = addAttribute(PositionIncrementAttribute.class);
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private AttributeSource.State current;
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* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, String[], int, int, int, boolean)} instead
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protected CompoundWordTokenFilterBase(TokenStream input, String[] dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
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this(Version.LUCENE_30, input, makeDictionary(Version.LUCENE_30, dictionary),minWordSize,minSubwordSize,maxSubwordSize, onlyLongestMatch);
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* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, String[], boolean)} instead
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protected CompoundWordTokenFilterBase(TokenStream input, String[] dictionary, boolean onlyLongestMatch) {
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this(Version.LUCENE_30, input, makeDictionary(Version.LUCENE_30, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
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* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, Set, boolean)} instead
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protected CompoundWordTokenFilterBase(TokenStream input, Set<?> dictionary, boolean onlyLongestMatch) {
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this(Version.LUCENE_30, input, dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
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* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, String[])} instead
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protected CompoundWordTokenFilterBase(TokenStream input, String[] dictionary) {
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this(Version.LUCENE_30, input, makeDictionary(Version.LUCENE_30, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
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* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, Set)} instead
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protected CompoundWordTokenFilterBase(TokenStream input, Set<?> dictionary) {
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this(Version.LUCENE_30, input, dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
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* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, Set, int, int, int, boolean)} instead
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protected CompoundWordTokenFilterBase(TokenStream input, Set<?> dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
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this(Version.LUCENE_30, input, dictionary, minWordSize, minSubwordSize, maxSubwordSize, onlyLongestMatch);
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protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, String[] dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
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this(matchVersion, input,makeDictionary(matchVersion, dictionary),minWordSize,minSubwordSize,maxSubwordSize, onlyLongestMatch);
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protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, String[] dictionary, boolean onlyLongestMatch) {
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this(matchVersion, input,makeDictionary(matchVersion, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
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protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, Set<?> dictionary, boolean onlyLongestMatch) {
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this(matchVersion, input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
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protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, String[] dictionary) {
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this(matchVersion, input,makeDictionary(matchVersion, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
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protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, Set<?> dictionary) {
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this(matchVersion, input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
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protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, Set<?> dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
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this.tokens=new LinkedList<CompoundToken>();
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this.minWordSize=minWordSize;
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this.minSubwordSize=minSubwordSize;
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this.maxSubwordSize=maxSubwordSize;
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this.onlyLongestMatch=onlyLongestMatch;
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if (dictionary==null || dictionary instanceof CharArraySet) {
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this.dictionary = (CharArraySet) dictionary;
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this.dictionary = new CharArraySet(matchVersion, dictionary, true);
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/** @deprecated Only available for backwards compatibility. */
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public static CharArraySet makeDictionary(final Version matchVersion, final String[] dictionary) {
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if (dictionary == null) {
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return new CharArraySet(matchVersion, Arrays.asList(dictionary), true);
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public final boolean incrementToken() throws IOException {
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if (!tokens.isEmpty()) {
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assert current != null;
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CompoundToken token = tokens.removeFirst();
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restoreState(current); // keep all other attributes untouched
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termAtt.setEmpty().append(token.txt);
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offsetAtt.setOffset(token.startOffset, token.endOffset);
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posIncAtt.setPositionIncrement(0);
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current = null; // not really needed, but for safety
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if (input.incrementToken()) {
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// Only words longer than minWordSize get processed
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if (termAtt.length() >= this.minWordSize) {
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// only capture the state if we really need it for producing new tokens
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if (!tokens.isEmpty()) {
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current = captureState();
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// return original token:
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/** Decomposes the current {@link #termAtt} and places {@link CompoundToken} instances in the {@link #tokens} list.
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* The original token may not be placed in the list, as it is automatically passed through this filter.
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protected abstract void decompose();
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public void reset() throws IOException {
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* Helper class to hold decompounded token information
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protected class CompoundToken {
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public final CharSequence txt;
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public final int startOffset, endOffset;
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/** Construct the compound token based on a slice of the current {@link CompoundWordTokenFilterBase#termAtt}. */
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public CompoundToken(int offset, int length) {
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final int newStart = CompoundWordTokenFilterBase.this.offsetAtt.startOffset() + offset;
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this.txt = CompoundWordTokenFilterBase.this.termAtt.subSequence(offset, offset + length);
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// TODO: This ignores the original endOffset, if a CharFilter/Tokenizer/Filter removed
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// chars from the term, offsets may not match correctly (other filters producing tokens
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// may also have this problem):
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this.startOffset = newStart;
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this.endOffset = newStart + length;