content: package org.apache.lucene.search.highlight;
  
  /**
   * 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.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.lucene.analysis.CachingTokenFilter;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
  import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.index.memory.MemoryIndex;
  import org.apache.lucene.search.Query;
  import org.apache.lucene.search.spans.SpanQuery;
  import org.apache.lucene.util.StringHelper;
  
  /**
   * {@link Scorer} implementation which scores text fragments by the number of
   * unique query terms found. This class converts appropriate {@link Query}s to
   * {@link SpanQuery}s and attempts to score only those terms that participated in
   * generating the 'hit' on the document.
   */
  public class QueryScorer implements Scorer {
    private float totalScore;
    private Set<String> foundTerms;
    private Map<String,WeightedSpanTerm> fieldWeightedSpanTerms;
    private float maxTermWeight;
    private int position = -1;
    private String defaultField;
    private CharTermAttribute termAtt;
    private PositionIncrementAttribute posIncAtt;
    private boolean expandMultiTermQuery = true;
    private Query query;
    private String field;
    private IndexReader reader;
    private boolean skipInitExtractor;
    private boolean wrapToCaching = true;
    private int maxCharsToAnalyze;
  
    /**
     * @param query Query to use for highlighting
     */
    public QueryScorer(Query query) {
      init(query, null, null, true);
    }
  
    /**
     * @param query Query to use for highlighting
     * @param field Field to highlight - pass null to ignore fields
     */
    public QueryScorer(Query query, String field) {
      init(query, field, null, true);
    }
  
    /**
     * @param query Query to use for highlighting
     * @param field Field to highlight - pass null to ignore fields
     * @param reader {@link IndexReader} to use for quasi tf/idf scoring
     */
    public QueryScorer(Query query, IndexReader reader, String field) {
      init(query, field, reader, true);
    }
  
  
    /**
     * @param query to use for highlighting
     * @param reader {@link IndexReader} to use for quasi tf/idf scoring
     * @param field to highlight - pass null to ignore fields
     * @param defaultField
     */
    public QueryScorer(Query query, IndexReader reader, String field, String defaultField) {
      this.defaultField = StringHelper.intern(defaultField);
      init(query, field, reader, true);
    }
  
    /**
     * @param defaultField - The default field for queries with the field name unspecified
     */
    public QueryScorer(Query query, String field, String defaultField) {
      this.defaultField = StringHelper.intern(defaultField);
      init(query, field, null, true);
    }
  
    /**
     * @param weightedTerms an array of pre-created {@link WeightedSpanTerm}s
     */
    public QueryScorer(WeightedSpanTerm[] weightedTerms) {
      this.fieldWeightedSpanTerms = new HashMap<String,WeightedSpanTerm>(weightedTerms.length);
  
      for (int i = 0; i < weightedTerms.length; i++) {
        WeightedSpanTerm existingTerm = fieldWeightedSpanTerms.get(weightedTerms[i].term);
  
        if ((existingTerm == null) ||
              (existingTerm.weight < weightedTerms[i].weight)) {
          // if a term is defined more than once, always use the highest
          // scoring weight
          fieldWeightedSpanTerms.put(weightedTerms[i].term, weightedTerms[i]);
          maxTermWeight = Math.max(maxTermWeight, weightedTerms[i].getWeight());
        }
      }
      skipInitExtractor = true;
    }
  
    /*
     * (non-Javadoc)
     *
     * @see org.apache.lucene.search.highlight.Scorer#getFragmentScore()
     */
    public float getFragmentScore() {
      return totalScore;
    }
  
    /**
     *
     * @return The highest weighted term (useful for passing to
     *         GradientFormatter to set top end of coloring scale).
     */
    public float getMaxTermWeight() {
      return maxTermWeight;
    }
  
    /*
     * (non-Javadoc)
     *
     * @see org.apache.lucene.search.highlight.Scorer#getTokenScore(org.apache.lucene.analysis.Token,
     *      int)
     */
    public float getTokenScore() {
      position += posIncAtt.getPositionIncrement();
      String termText = termAtt.toString();
  
      WeightedSpanTerm weightedSpanTerm;
  
      if ((weightedSpanTerm = fieldWeightedSpanTerms.get(
                termText)) == null) {
        return 0;
      }
  
      if (weightedSpanTerm.positionSensitive &&
            !weightedSpanTerm.checkPosition(position)) {
        return 0;
      }
  
      float score = weightedSpanTerm.getWeight();
  
      // found a query term - is it unique in this doc?
      if (!foundTerms.contains(termText)) {
        totalScore += score;
        foundTerms.add(termText);
      }
  
      return score;
    }
  
    /* (non-Javadoc)
     * @see org.apache.lucene.search.highlight.Scorer#init(org.apache.lucene.analysis.TokenStream)
     */
    public TokenStream init(TokenStream tokenStream) throws IOException {
      position = -1;
      termAtt = tokenStream.addAttribute(CharTermAttribute.class);
      posIncAtt = tokenStream.addAttribute(PositionIncrementAttribute.class);
      if(!skipInitExtractor) {
        if(fieldWeightedSpanTerms != null) {
          fieldWeightedSpanTerms.clear();
        }
        return initExtractor(tokenStream);
      }
      return null;
    }
    
    /**
     * Retrieve the {@link WeightedSpanTerm} for the specified token. Useful for passing
     * Span information to a {@link Fragmenter}.
     *
     * @param token to get {@link WeightedSpanTerm} for
     * @return WeightedSpanTerm for token
     */
    public WeightedSpanTerm getWeightedSpanTerm(String token) {
      return fieldWeightedSpanTerms.get(token);
    }
  
    /**
     */
    private void init(Query query, String field, IndexReader reader, boolean expandMultiTermQuery) {
      this.reader = reader;
      this.expandMultiTermQuery = expandMultiTermQuery;
      this.query = query;
      this.field = field;
    }
    
    private TokenStream initExtractor(TokenStream tokenStream) throws IOException {
      WeightedSpanTermExtractor qse = defaultField == null ? new WeightedSpanTermExtractor()
          : new WeightedSpanTermExtractor(defaultField);
      qse.setMaxDocCharsToAnalyze(maxCharsToAnalyze);
      qse.setExpandMultiTermQuery(expandMultiTermQuery);
      qse.setWrapIfNotCachingTokenFilter(wrapToCaching);
      if (reader == null) {
        this.fieldWeightedSpanTerms = qse.getWeightedSpanTerms(query,
            tokenStream, field);
      } else {
        this.fieldWeightedSpanTerms = qse.getWeightedSpanTermsWithScores(query,
            tokenStream, field, reader);
      }
      if(qse.isCachedTokenStream()) {
        return qse.getTokenStream();
      }
      
      return null;
    }
  
    /*
     * (non-Javadoc)
     *
     * @see org.apache.lucene.search.highlight.Scorer#startFragment(org.apache.lucene.search.highlight.TextFragment)
     */
    public void startFragment(TextFragment newFragment) {
      foundTerms = new HashSet<String>();
      totalScore = 0;
    }
    
    /**
     * @return true if multi-term queries should be expanded
     */
    public boolean isExpandMultiTermQuery() {
      return expandMultiTermQuery;
    }
  
    /**
     * Controls whether or not multi-term queries are expanded
     * against a {@link MemoryIndex} {@link IndexReader}.
     * 
     * @param expandMultiTermQuery true if multi-term queries should be expanded
     */
    public void setExpandMultiTermQuery(boolean expandMultiTermQuery) {
      this.expandMultiTermQuery = expandMultiTermQuery;
    }
    
    /**
     * By default, {@link TokenStream}s that are not of the type
     * {@link CachingTokenFilter} are wrapped in a {@link CachingTokenFilter} to
     * ensure an efficient reset - if you are already using a different caching
     * {@link TokenStream} impl and you don't want it to be wrapped, set this to
     * false.
     * 
     * @param wrap
     */
    public void setWrapIfNotCachingTokenFilter(boolean wrap) {
      this.wrapToCaching = wrap;
    }
  
    public void setMaxDocCharsToAnalyze(int maxDocCharsToAnalyze) {
      this.maxCharsToAnalyze = maxDocCharsToAnalyze;
    }
  }
  