content: package org.apache.lucene.search.payloads;
  
  import org.apache.lucene.search.Explanation;
  /**
   * 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.
   */
  
  
  /**
   * Returns the maximum payload score seen, else 1 if there are no payloads on the doc.
   * <p/>
   * Is thread safe and completely reusable.
   *
   **/
  public class MaxPayloadFunction extends PayloadFunction {
    @Override
    public float currentScore(int docId, String field, int start, int end, int numPayloadsSeen, float currentScore, float currentPayloadScore) {
      if (numPayloadsSeen == 0) {
        return currentPayloadScore;
      } else {
        return Math.max(currentPayloadScore, currentScore);
      }
    }
  
    @Override
    public float docScore(int docId, String field, int numPayloadsSeen, float payloadScore) {
      return numPayloadsSeen > 0 ? payloadScore : 1;
    }
    
    @Override
    public Explanation explain(int doc, int numPayloadsSeen, float payloadScore) {
  	    Explanation expl = new Explanation();
  	    float maxPayloadScore = (numPayloadsSeen > 0 ? payloadScore : 1);
  	    expl.setValue(maxPayloadScore);
  	    expl.setDescription("MaxPayloadFunction(...)");
  	    return expl;
  	  } 
    @Override
    public int hashCode() {
      final int prime = 31;
      int result = 1;
      result = prime * result + this.getClass().hashCode();
      return result;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj)
        return true;
      if (obj == null)
        return false;
      if (getClass() != obj.getClass())
        return false;
      return true;
    }
  }
  