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Lucene example source code file (AveragePayloadFunction.java)

This example Lucene source code file (AveragePayloadFunction.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

averagepayloadfunction, averagepayloadfunction, explanation, explanation, override, override, payloadfunction, string, string

The Lucene AveragePayloadFunction.java source code

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,
 * See the License for the specific language governing permissions and
 * limitations under the License.

 * Calculate the final score as the average score of all payloads seen.
 * <p/>
 * Is thread safe and completely reusable. 
public class AveragePayloadFunction extends PayloadFunction{

  public float currentScore(int docId, String field, int start, int end, int numPayloadsSeen, float currentScore, float currentPayloadScore) {
    return currentPayloadScore + currentScore;

  public float docScore(int docId, String field, int numPayloadsSeen, float payloadScore) {
    return numPayloadsSeen > 0 ? (payloadScore / numPayloadsSeen) : 1;
  public Explanation explain(int doc, int numPayloadsSeen, float payloadScore) {
      Explanation payloadBoost = new Explanation();
      float avgPayloadScore = (numPayloadsSeen > 0 ? (payloadScore / numPayloadsSeen) : 1);
      return payloadBoost;

  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + this.getClass().hashCode();
    return result;

  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    return true;

Other Lucene examples (source code examples)

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