content: 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;
      }
  
    }  
  }
  