content: package org.apache.solr.search.function.distance;
  /**
   * 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.Searcher;
  import org.apache.lucene.spatial.DistanceUtils;
  import org.apache.solr.common.SolrException;
  import org.apache.solr.search.function.MultiValueSource;
  import org.apache.solr.search.function.DocValues;
  import org.apache.solr.search.function.ValueSource;
  
  import java.io.IOException;
  import java.util.Map;
  
  
  /**
   * Calculate the Haversine formula (distance) between any two points on a sphere
   * Takes in four value sources: (latA, lonA); (latB, lonB).
   * <p/>
   * Assumes the value sources are in radians unless
   * <p/>
   * See http://en.wikipedia.org/wiki/Great-circle_distance and
   * http://en.wikipedia.org/wiki/Haversine_formula for the actual formula and
   * also http://www.movable-type.co.uk/scripts/latlong.html
   */
  public class HaversineFunction extends ValueSource {
  
    private MultiValueSource p1;
    private MultiValueSource p2;
    private boolean convertToRadians = false;
    private double radius;
  
    public HaversineFunction(MultiValueSource p1, MultiValueSource p2, double radius) {
      this(p1, p2, radius, false);
    }
  
    public HaversineFunction(MultiValueSource p1, MultiValueSource p2, double radius, boolean convertToRads){
      this.p1 = p1;
      this.p2 = p2;
      if (p1.dimension() != 2 || p2.dimension() != 2) {
        throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, "Illegal dimension for value sources");
      }
      this.radius = radius;
      this.convertToRadians = convertToRads;
    }
  
    protected String name() {
      return "hsin";
    }
  
    /**
     * @param doc  The doc to score
     * @param p1DV
     * @param p2DV
     * @return The haversine distance formula
     */
    protected double distance(int doc, DocValues p1DV, DocValues p2DV) {
  
      double[] p1D = new double[2];
      double[] p2D = new double[2];
      p1DV.doubleVal(doc, p1D);
      p2DV.doubleVal(doc, p2D);
      double x1;
      double y1;
      double x2;
      double y2;
      if (convertToRadians) {
        x1 = p1D[0] * DistanceUtils.DEGREES_TO_RADIANS;
        y1 = p1D[1] * DistanceUtils.DEGREES_TO_RADIANS;
        x2 = p2D[0] * DistanceUtils.DEGREES_TO_RADIANS;
        y2 = p2D[1] * DistanceUtils.DEGREES_TO_RADIANS;
      } else {
        x1 = p1D[0];
        y1 = p1D[1];
        x2 = p2D[0];
        y2 = p2D[1];
      }
      return DistanceUtils.haversine(x1, y1, x2, y2, radius);
    }
  
  
    @Override
    public DocValues getValues(Map context, IndexReader reader) throws IOException {
      final DocValues vals1 = p1.getValues(context, reader);
  
      final DocValues vals2 = p2.getValues(context, reader);
      return new DocValues() {
        @Override
        public float floatVal(int doc) {
          return (float) doubleVal(doc);
        }
  
        @Override
        public int intVal(int doc) {
          return (int) doubleVal(doc);
        }
  
        @Override
        public long longVal(int doc) {
          return (long) doubleVal(doc);
        }
  
        @Override
        public double doubleVal(int doc) {
          return distance(doc, vals1, vals2);
        }
  
        @Override
        public String strVal(int doc) {
          return Double.toString(doubleVal(doc));
        }
  
        @Override
        public String toString(int doc) {
          StringBuilder sb = new StringBuilder();
          sb.append(name()).append('(');
          sb.append(vals1.toString(doc)).append(',').append(vals2.toString(doc));
          sb.append(')');
          return sb.toString();
        }
      };
    }
  
    @Override
    public void createWeight(Map context, Searcher searcher) throws IOException {
      p1.createWeight(context, searcher);
      p2.createWeight(context, searcher);
  
    }
  
    @Override
    public boolean equals(Object o) {
      if (this.getClass() != o.getClass()) return false;
      HaversineFunction other = (HaversineFunction) o;
      return this.name().equals(other.name())
              && p1.equals(other.p1) &&
              p2.equals(other.p2) && radius == other.radius;
    }
  
    @Override
    public int hashCode() {
      int result;
      long temp;
      result = p1.hashCode();
      result = 31 * result + p2.hashCode();
      result = 31 * result + name().hashCode();
      temp = Double.doubleToRawLongBits(radius);
      result = 31 * result + (int) (temp ^ (temp >>> 32));
      return result;
    }
  
    @Override
    public String description() {
      StringBuilder sb = new StringBuilder();
      sb.append(name()).append('(');
      sb.append(p1).append(',').append(p2);
      sb.append(')');
      return sb.toString();
    }
  }
  