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.lucene.spatial.tier;
  
  import org.apache.lucene.spatial.DistanceUtils;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * Provide a high level access point to distances
   * Used by DistanceSortSource and DistanceQuery
   *  
   * <p><font color="red"><b>NOTE:</b> This API is still in
   * flux and might change in incompatible ways in the next
   * release.</font>
   *
   */
  public class DistanceHandler {
  
    public enum Precision {EXACT, TWOFEET, TWENTYFEET, TWOHUNDREDFEET}
    
    private Map<Integer,Double> distances;
    private Map<String, Double> distanceLookupCache;
    private Precision precise;
    
    public DistanceHandler (Map<Integer,Double> distances, Map<String, Double> distanceLookupCache, Precision precise){
      this.distances = distances;
      this.distanceLookupCache = distanceLookupCache;
      this.precise = precise; 
    }
    
    
    public static double getPrecision(double x, Precision thisPrecise){
      
      if(thisPrecise != null){
        double dif = 0;
        switch(thisPrecise) {
          case EXACT: return x;
          case TWOFEET:        dif = x % 0.0001; break;
          case TWENTYFEET:     dif = x % 0.001;  break;
          case TWOHUNDREDFEET: dif = x % 0.01; break;
        }
        return x - dif;
      }
      return x;
    }
    
    public Precision getPrecision() {
      return precise;
    }
    
    public double getDistance(int docid, double centerLat, double centerLng, double lat, double lng){
    
      // check to see if we have distances
      // if not calculate the distance
      if(distances == null){
        return DistanceUtils.getDistanceMi(centerLat, centerLng, lat, lng);
      }
      
      // check to see if the doc id has a cached distance
      Double docd = distances.get( docid );
      if (docd != null){
        return docd.doubleValue();
      }
      
      //check to see if we have a precision code
      // and if another lat/long has been calculated at
      // that rounded location
      if (precise != null) {
        double xLat = getPrecision(lat, precise);
        double xLng = getPrecision(lng, precise);
        
        String k = Double.valueOf(xLat).toString() +","+ Double.valueOf(xLng).toString();
      
        Double d = (distanceLookupCache.get(k));
        if (d != null){
          return d.doubleValue();
        }
      }
      
      //all else fails calculate the distances    
      return DistanceUtils.getDistanceMi(centerLat, centerLng, lat, lng);
    }
    
    
    public static void main(String args[]){ 
      DistanceHandler db = new DistanceHandler(new HashMap<Integer,Double>(), new HashMap<String,Double>(), Precision.TWOHUNDREDFEET);
      System.out.println(DistanceHandler.getPrecision(-1234.123456789, db.getPrecision()));
    }
  }
  