Lucene example source code file (MinPayloadFunction.java)

This example Lucene source code file (MinPayloadFunction.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

explanation, explanation, minpayloadfunction, minpayloadfunction, override, override, payloadfunction, string, string

The Lucene MinPayloadFunction.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,
 * 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.
 */

/**
 * Calculates the minimum payload seen
 *
 **/
public class MinPayloadFunction 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.min(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 minPayloadScore = (numPayloadsSeen > 0 ? payloadScore : 1);
	  expl.setValue(minPayloadScore);
	  expl.setDescription("MinPayloadFunction(...)");
	  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;
  }

}