content: /**
   * 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.
   */
  
  package org.apache.solr.schema;
  
  import org.apache.lucene.document.Fieldable;
  import org.apache.lucene.search.Query;
  import org.apache.lucene.search.SortField;
  import org.apache.lucene.spatial.DistanceUtils;
  import org.apache.lucene.spatial.geohash.GeoHashUtils;
  import org.apache.lucene.spatial.tier.InvalidGeoException;
  import org.apache.solr.common.SolrException;
  import org.apache.solr.response.TextResponseWriter;
  import org.apache.solr.response.XMLWriter;
  import org.apache.solr.search.QParser;
  import org.apache.solr.search.SolrConstantScoreQuery;
  import org.apache.solr.search.SpatialOptions;
  import org.apache.solr.search.function.LiteralValueSource;
  import org.apache.solr.search.function.ValueSource;
  import org.apache.solr.search.function.ValueSourceRangeFilter;
  import org.apache.solr.search.function.distance.GeohashHaversineFunction;
  
  
  import java.io.IOException;
  
  /**
   * This is a class that represents a <a
   * href="http://en.wikipedia.org/wiki/Geohash">Geohash</a> field. The field is
   * provided as a lat/lon pair and is internally represented as a string.
   *
   * @see org.apache.lucene.spatial.DistanceUtils#parseLatitudeLongitude(double[], String)
   */
  public class GeoHashField extends FieldType implements SpatialQueryable {
  
  
    @Override
    public SortField getSortField(SchemaField field, boolean top) {
      return getStringSort(field, top);
    }
  
      //QUESTION: Should we do a fast and crude one?  Or actually check distances
    //Fast and crude could use EdgeNGrams, but that would require a different
    //encoding.  Plus there are issues around the Equator/Prime Meridian
    public Query createSpatialQuery(QParser parser, SpatialOptions options) {
      double [] point = new double[0];
      try {
        point = DistanceUtils.parsePointDouble(null, options.pointStr, 2);
      } catch (InvalidGeoException e) {
        throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, e);
      }
      String geohash = GeoHashUtils.encode(point[0], point[1]);
      //TODO: optimize this
      return new SolrConstantScoreQuery(new ValueSourceRangeFilter(new GeohashHaversineFunction(getValueSource(options.field, parser),
              new LiteralValueSource(geohash), options.radius), "0", String.valueOf(options.distance), true, true));
    }
  
    @Override
    public void write(XMLWriter xmlWriter, String name, Fieldable f)
            throws IOException {
      xmlWriter.writeStr(name, toExternal(f));
    }
  
    @Override
    public void write(TextResponseWriter writer, String name, Fieldable f)
            throws IOException {
      writer.writeStr(name, toExternal(f), false);
    }
  
  
    @Override
    public String toExternal(Fieldable f) {
      double[] latLon = GeoHashUtils.decode(f.stringValue());
      return latLon[0] + "," + latLon[1];
    }
  
  
    @Override
    public String toInternal(String val) {
      // validate that the string is of the form
      // latitude, longitude
      double[] latLon = new double[0];
      try {
        latLon = DistanceUtils.parseLatitudeLongitude(null, val);
      } catch (InvalidGeoException e) {
        throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, e);
      }
      return GeoHashUtils.encode(latLon[0], latLon[1]);
    }
  
  
    @Override
    public ValueSource getValueSource(SchemaField field, QParser parser) {
      field.checkFieldCacheSource(parser);
      return new StrFieldSource(field.name);
    }
  
  
  }
  