package org.apache.lucene.analysis.compound;
/**
* 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 java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedList;
import java.util.Locale;
import java.util.Set;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.Version;
/**
* Base class for decomposition token filters.
* <p>
* You must specify the required {@link Version} compatibility when creating
* CompoundWordTokenFilterBase:
* <ul>
* <li>As of 3.1, CompoundWordTokenFilterBase correctly handles Unicode 4.0
* supplementary characters in strings and char arrays provided as compound word
* dictionaries.
* </ul>
* <p>If you pass in a {@link org.apache.lucene.analysis.CharArraySet} as dictionary,
* it should be case-insensitive unless it contains only lowercased entries and you
* have {@link org.apache.lucene.analysis.LowerCaseFilter} before this filter in your analysis chain.
* For optional performance (as this filter does lots of lookups to the dictionary,
* you should use the latter analysis chain/CharArraySet). Be aware: If you supply arbitrary
* {@link Set Sets} to the ctors or {@code String[]} dictionaries, they will be automatically
* transformed to case-insensitive!
*/
public abstract class CompoundWordTokenFilterBase extends TokenFilter {
/**
* The default for minimal word length that gets decomposed
*/
public static final int DEFAULT_MIN_WORD_SIZE = 5;
/**
* The default for minimal length of subwords that get propagated to the output of this filter
*/
public static final int DEFAULT_MIN_SUBWORD_SIZE = 2;
/**
* The default for maximal length of subwords that get propagated to the output of this filter
*/
public static final int DEFAULT_MAX_SUBWORD_SIZE = 15;
protected final CharArraySet dictionary;
protected final LinkedList<CompoundToken> tokens;
protected final int minWordSize;
protected final int minSubwordSize;
protected final int maxSubwordSize;
protected final boolean onlyLongestMatch;
protected final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
protected final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
private final PositionIncrementAttribute posIncAtt = addAttribute(PositionIncrementAttribute.class);
private AttributeSource.State current;
/**
* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, String[], int, int, int, boolean)} instead
*/
@Deprecated
protected CompoundWordTokenFilterBase(TokenStream input, String[] dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
this(Version.LUCENE_30, input, makeDictionary(Version.LUCENE_30, dictionary),minWordSize,minSubwordSize,maxSubwordSize, onlyLongestMatch);
}
/**
* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, String[], boolean)} instead
*/
@Deprecated
protected CompoundWordTokenFilterBase(TokenStream input, String[] dictionary, boolean onlyLongestMatch) {
this(Version.LUCENE_30, input, makeDictionary(Version.LUCENE_30, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
}
/**
* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, Set, boolean)} instead
*/
@Deprecated
protected CompoundWordTokenFilterBase(TokenStream input, Set<?> dictionary, boolean onlyLongestMatch) {
this(Version.LUCENE_30, input, dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
}
/**
* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, String[])} instead
*/
@Deprecated
protected CompoundWordTokenFilterBase(TokenStream input, String[] dictionary) {
this(Version.LUCENE_30, input, makeDictionary(Version.LUCENE_30, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
}
/**
* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, Set)} instead
*/
@Deprecated
protected CompoundWordTokenFilterBase(TokenStream input, Set<?> dictionary) {
this(Version.LUCENE_30, input, dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
}
/**
* @deprecated use {@link #CompoundWordTokenFilterBase(Version, TokenStream, Set, int, int, int, boolean)} instead
*/
@Deprecated
protected CompoundWordTokenFilterBase(TokenStream input, Set<?> dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
this(Version.LUCENE_30, input, dictionary, minWordSize, minSubwordSize, maxSubwordSize, onlyLongestMatch);
}
protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, String[] dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
this(matchVersion, input,makeDictionary(matchVersion, dictionary),minWordSize,minSubwordSize,maxSubwordSize, onlyLongestMatch);
}
protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, String[] dictionary, boolean onlyLongestMatch) {
this(matchVersion, input,makeDictionary(matchVersion, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
}
protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, Set<?> dictionary, boolean onlyLongestMatch) {
this(matchVersion, input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, onlyLongestMatch);
}
protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, String[] dictionary) {
this(matchVersion, input,makeDictionary(matchVersion, dictionary),DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
}
protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, Set<?> dictionary) {
this(matchVersion, input,dictionary,DEFAULT_MIN_WORD_SIZE,DEFAULT_MIN_SUBWORD_SIZE,DEFAULT_MAX_SUBWORD_SIZE, false);
}
protected CompoundWordTokenFilterBase(Version matchVersion, TokenStream input, Set<?> dictionary, int minWordSize, int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
super(input);
this.tokens=new LinkedList<CompoundToken>();
this.minWordSize=minWordSize;
this.minSubwordSize=minSubwordSize;
this.maxSubwordSize=maxSubwordSize;
this.onlyLongestMatch=onlyLongestMatch;
if (dictionary==null || dictionary instanceof CharArraySet) {
this.dictionary = (CharArraySet) dictionary;
} else {
this.dictionary = new CharArraySet(matchVersion, dictionary, true);
}
}
/** @deprecated Only available for backwards compatibility. */
@Deprecated
public static CharArraySet makeDictionary(final Version matchVersion, final String[] dictionary) {
if (dictionary == null) {
return null;
}
return new CharArraySet(matchVersion, Arrays.asList(dictionary), true);
}
@Override
public final boolean incrementToken() throws IOException {
if (!tokens.isEmpty()) {
assert current != null;
CompoundToken token = tokens.removeFirst();
restoreState(current); // keep all other attributes untouched
termAtt.setEmpty().append(token.txt);
offsetAtt.setOffset(token.startOffset, token.endOffset);
posIncAtt.setPositionIncrement(0);
return true;
}
current = null; // not really needed, but for safety
if (input.incrementToken()) {
// Only words longer than minWordSize get processed
if (termAtt.length() >= this.minWordSize) {
decompose();
// only capture the state if we really need it for producing new tokens
if (!tokens.isEmpty()) {
current = captureState();
}
}
// return original token:
return true;
} else {
return false;
}
}
/** Decomposes the current {@link #termAtt} and places {@link CompoundToken} instances in the {@link #tokens} list.
* The original token may not be placed in the list, as it is automatically passed through this filter.
*/
protected abstract void decompose();
@Override
public void reset() throws IOException {
super.reset();
tokens.clear();
current = null;
}
/**
* Helper class to hold decompounded token information
*/
protected class CompoundToken {
public final CharSequence txt;
public final int startOffset, endOffset;
/** Construct the compound token based on a slice of the current {@link CompoundWordTokenFilterBase#termAtt}. */
public CompoundToken(int offset, int length) {
final int newStart = CompoundWordTokenFilterBase.this.offsetAtt.startOffset() + offset;
this.txt = CompoundWordTokenFilterBase.this.termAtt.subSequence(offset, offset + length);
// TODO: This ignores the original endOffset, if a CharFilter/Tokenizer/Filter removed
// chars from the term, offsets may not match correctly (other filters producing tokens
// may also have this problem):
this.startOffset = newStart;
this.endOffset = newStart + length;
}
}
}