content: package org.apache.lucene.search.payloads;
  
  /**
   * 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.index.IndexReader;
  import org.apache.lucene.search.Explanation;
  import org.apache.lucene.search.Scorer;
  import org.apache.lucene.search.Searcher;
  import org.apache.lucene.search.Similarity;
  import org.apache.lucene.search.Weight;
  import org.apache.lucene.search.spans.NearSpansOrdered;
  import org.apache.lucene.search.spans.NearSpansUnordered;
  import org.apache.lucene.search.spans.SpanNearQuery;
  import org.apache.lucene.search.spans.SpanQuery;
  import org.apache.lucene.search.spans.SpanScorer;
  import org.apache.lucene.search.spans.SpanWeight;
  import org.apache.lucene.search.spans.Spans;
  import org.apache.lucene.util.ToStringUtils;
  
  import java.io.IOException;
  import java.util.Collection;
  import java.util.Iterator;
  
  /**
   * This class is very similar to
   * {@link org.apache.lucene.search.spans.SpanNearQuery} except that it factors
   * in the value of the payloads located at each of the positions where the
   * {@link org.apache.lucene.search.spans.TermSpans} occurs.
   * <p/>
   * In order to take advantage of this, you must override
   * {@link org.apache.lucene.search.Similarity#scorePayload}
   * which returns 1 by default.
   * <p/>
   * Payload scores are aggregated using a pluggable {@link PayloadFunction}.
   * 
   * @see org.apache.lucene.search.Similarity#scorePayload
   */
  public class PayloadNearQuery extends SpanNearQuery {
    protected String fieldName;
    protected PayloadFunction function;
  
    public PayloadNearQuery(SpanQuery[] clauses, int slop, boolean inOrder) {
      this(clauses, slop, inOrder, new AveragePayloadFunction());
    }
  
    public PayloadNearQuery(SpanQuery[] clauses, int slop, boolean inOrder,
        PayloadFunction function) {
      super(clauses, slop, inOrder);
      fieldName = clauses[0].getField(); // all clauses must have same field
      this.function = function;
    }
  
    @Override
    public Weight createWeight(Searcher searcher) throws IOException {
      return new PayloadNearSpanWeight(this, searcher);
    }
  
    @Override
    public Object clone() {
      int sz = clauses.size();
      SpanQuery[] newClauses = new SpanQuery[sz];
  
      for (int i = 0; i < sz; i++) {
        newClauses[i] = (SpanQuery) clauses.get(i).clone();
      }
      PayloadNearQuery boostingNearQuery = new PayloadNearQuery(newClauses, slop,
          inOrder, function);
      boostingNearQuery.setBoost(getBoost());
      return boostingNearQuery;
    }
  
    @Override
    public String toString(String field) {
      StringBuilder buffer = new StringBuilder();
      buffer.append("payloadNear([");
      Iterator<SpanQuery> i = clauses.iterator();
      while (i.hasNext()) {
        SpanQuery clause = i.next();
        buffer.append(clause.toString(field));
        if (i.hasNext()) {
          buffer.append(", ");
        }
      }
      buffer.append("], ");
      buffer.append(slop);
      buffer.append(", ");
      buffer.append(inOrder);
      buffer.append(")");
      buffer.append(ToStringUtils.boost(getBoost()));
      return buffer.toString();
    }
  
    @Override
    public int hashCode() {
      final int prime = 31;
      int result = super.hashCode();
      result = prime * result + ((fieldName == null) ? 0 : fieldName.hashCode());
      result = prime * result + ((function == null) ? 0 : function.hashCode());
      return result;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj)
        return true;
      if (!super.equals(obj))
        return false;
      if (getClass() != obj.getClass())
        return false;
      PayloadNearQuery other = (PayloadNearQuery) obj;
      if (fieldName == null) {
        if (other.fieldName != null)
          return false;
      } else if (!fieldName.equals(other.fieldName))
        return false;
      if (function == null) {
        if (other.function != null)
          return false;
      } else if (!function.equals(other.function))
        return false;
      return true;
    }
  
    public class PayloadNearSpanWeight extends SpanWeight {
      public PayloadNearSpanWeight(SpanQuery query, Searcher searcher)
          throws IOException {
        super(query, searcher);
      }
  
      @Override
      public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder,
          boolean topScorer) throws IOException {
        return new PayloadNearSpanScorer(query.getSpans(reader), this,
            similarity, reader.norms(query.getField()));
      }
    }
  
    public class PayloadNearSpanScorer extends SpanScorer {
      Spans spans;
      protected float payloadScore;
      private int payloadsSeen;
      Similarity similarity = getSimilarity();
  
      protected PayloadNearSpanScorer(Spans spans, Weight weight,
          Similarity similarity, byte[] norms) throws IOException {
        super(spans, weight, similarity, norms);
        this.spans = spans;
      }
  
      // Get the payloads associated with all underlying subspans
      public void getPayloads(Spans[] subSpans) throws IOException {
        for (int i = 0; i < subSpans.length; i++) {
          if (subSpans[i] instanceof NearSpansOrdered) {
            if (((NearSpansOrdered) subSpans[i]).isPayloadAvailable()) {
              processPayloads(((NearSpansOrdered) subSpans[i]).getPayload(),
                  subSpans[i].start(), subSpans[i].end());
            }
            getPayloads(((NearSpansOrdered) subSpans[i]).getSubSpans());
          } else if (subSpans[i] instanceof NearSpansUnordered) {
            if (((NearSpansUnordered) subSpans[i]).isPayloadAvailable()) {
              processPayloads(((NearSpansUnordered) subSpans[i]).getPayload(),
                  subSpans[i].start(), subSpans[i].end());
            }
            getPayloads(((NearSpansUnordered) subSpans[i]).getSubSpans());
          }
        }
      }
  
      /**
       * By default, uses the {@link PayloadFunction} to score the payloads, but
       * can be overridden to do other things.
       * 
       * @param payLoads The payloads
       * @param start The start position of the span being scored
       * @param end The end position of the span being scored
       * 
       * @see Spans
       */
      protected void processPayloads(Collection<byte[]> payLoads, int start, int end) {
        for (final byte[] thePayload : payLoads) {
          payloadScore = function.currentScore(doc, fieldName, start, end,
              payloadsSeen, payloadScore, similarity.scorePayload(doc, fieldName,
                  spans.start(), spans.end(), thePayload, 0, thePayload.length));
          ++payloadsSeen;
        }
      }
  
      //
      @Override
      protected boolean setFreqCurrentDoc() throws IOException {
          if (!more) {
              return false;
            }
            doc = spans.doc();
            freq = 0.0f;
            payloadScore = 0;
            payloadsSeen = 0;
            do {
              int matchLength = spans.end() - spans.start();
              freq += getSimilarity().sloppyFreq(matchLength);
              Spans[] spansArr = new Spans[1];
              spansArr[0] = spans;
              getPayloads(spansArr);            
              more = spans.next();
            } while (more && (doc == spans.doc()));
            return true;    	
      }
  
      @Override
      public float score() throws IOException {
  
        return super.score()
            * function.docScore(doc, fieldName, payloadsSeen, payloadScore);
      }
  
      @Override
      protected Explanation explain(int doc) throws IOException {
        Explanation result = new Explanation();
        // Add detail about tf/idf...
        Explanation nonPayloadExpl = super.explain(doc);
        result.addDetail(nonPayloadExpl);
        // Add detail about payload
        Explanation payloadExpl = function.explain(doc, payloadsSeen, payloadScore);
        result.addDetail(payloadExpl);
        result.setValue(nonPayloadExpl.getValue() * payloadExpl.getValue());
        result.setDescription("PayloadNearQuery, product of:");
        return result;
      }
    }
  
  }
  