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.spatial.DistanceUtils;
import org.apache.solr.search.function.ValueSource;
import org.apache.solr.search.function.DocValues;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.spatial.geohash.GeoHashUtils;
import java.util.Map;
import java.io.IOException;
/**
* Calculate the Haversine distance between two geo hash codes.
*
* <p/>
* Ex: ghhsin(ValueSource, ValueSource, radius)
* <p/>
*
* @see org.apache.solr.search.function.distance.HaversineFunction for more details on the implementation
*
**/
public class GeohashHaversineFunction extends ValueSource {
private ValueSource geoHash1, geoHash2;
private double radius;
public GeohashHaversineFunction(ValueSource geoHash1, ValueSource geoHash2, double radius) {
this.geoHash1 = geoHash1;
this.geoHash2 = geoHash2;
this.radius = radius;
}
protected String name() {
return "ghhsin";
}
@Override
public DocValues getValues(Map context, IndexReader reader) throws IOException {
final DocValues gh1DV = geoHash1.getValues(context, reader);
final DocValues gh2DV = geoHash2.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, gh1DV, gh2DV);
}
@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(gh1DV.toString(doc)).append(',').append(gh2DV.toString(doc));
sb.append(')');
return sb.toString();
}
};
}
protected double distance(int doc, DocValues gh1DV, DocValues gh2DV) {
double result = 0;
String h1 = gh1DV.strVal(doc);
String h2 = gh2DV.strVal(doc);
if (h1 != null && h2 != null && h1.equals(h2) == false){
//TODO: If one of the hashes is a literal value source, seems like we could cache it
//and avoid decoding every time
double[] h1Pair = GeoHashUtils.decode(h1);
double[] h2Pair = GeoHashUtils.decode(h2);
result = DistanceUtils.haversine(Math.toRadians(h1Pair[0]), Math.toRadians(h1Pair[1]),
Math.toRadians(h2Pair[0]), Math.toRadians(h2Pair[1]), radius);
} else if (h1 == null || h2 == null){
result = Double.MAX_VALUE;
}
return result;
}
@Override
public void createWeight(Map context, Searcher searcher) throws IOException {
geoHash1.createWeight(context, searcher);
geoHash2.createWeight(context, searcher);
}
@Override
public boolean equals(Object o) {
if (this.getClass() != o.getClass()) return false;
GeohashHaversineFunction other = (GeohashHaversineFunction) o;
return this.name().equals(other.name())
&& geoHash1.equals(other.geoHash1) &&
geoHash2.equals(other.geoHash2) &&
radius == other.radius;
}
@Override
public int hashCode() {
int result;
result = geoHash1.hashCode();
result = 31 * result + geoHash2.hashCode();
result = 31 * result + name().hashCode();
long 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(geoHash1).append(',').append(geoHash2);
sb.append(')');
return sb.toString();
}
}