Lucene example source code file (LLRect.java)

This example Lucene source code file (LLRect.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

floatlatlng, floatlatlng, latlng, latlng, llrect, llrect, override, override, r, rectangle, string

The Lucene LLRect.java source code

/**
 * 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.geometry.shape;

import org.apache.lucene.spatial.geometry.FloatLatLng;
import org.apache.lucene.spatial.geometry.LatLng;



/**
 * Lat-long rect.  Instances are mutable.
 *
 * <p>NOTE: This API is still in
 * flux and might change in incompatible ways in the next
 * release.</font>
 */
public class LLRect {
  private LatLng ll, ur;
  
  public LLRect(LatLng ll, LatLng ur) {
    this.ll=ll;
    this.ur=ur;
  }
  
  public LLRect(LLRect other) {
    this.ll=other.ll;
    this.ur=other.ur;
  }
  
  /**
   * Return the area in units of lat-lng squared.  This is a contrived unit
   * that only has value when comparing to something else.
   */
  public double area() {
    return Math.abs((ll.getLat()-ur.getLat()) * (ll.getLng()-ur.getLng()));
  }

  public LatLng getLowerLeft() {
    return ll;
  }
  
  public LatLng getUpperRight() {
    return ur;
  }
  
  @Override
  public String toString() {
    return "{" + ll + ", " + ur + "}";
  }

  public LatLng getMidpoint() {
    return ll.calculateMidpoint(ur);
  }

  /**
   * Approximates a box centered at the given point with the given width and height in miles.
   * @param center
   * @param widthMi
   * @param heightMi
   */
  public static LLRect createBox(LatLng center, double widthMi, double heightMi) {
    double d = widthMi;
    LatLng ur = boxCorners(center, d, 45.0); // assume right angles
    LatLng ll = boxCorners(center, d, 225.0);

    //System.err.println("boxCorners: ur " + ur.getLat() + ',' + ur.getLng());
    //System.err.println("boxCorners: cnt " + center.getLat() + ',' + center.getLng());
    //System.err.println("boxCorners: ll " + ll.getLat() + ',' + ll.getLng());
    return new LLRect(ll, ur);
  }
  
  /**
   * Returns a rectangle shape for the bounding box
   */
  public Rectangle toRectangle() {
    return new Rectangle(ll.getLng(), ll.getLat(), ur.getLng(), ur.getLat());
  }

  private static LatLng boxCorners(LatLng center, double d, double brngdeg) {
    double a = center.getLat();
    double b = center.getLng();
    double R = 3963.0; // radius of earth in miles
    double brng = (Math.PI*brngdeg/180);
    double lat1 = (Math.PI*a/180);
    double lon1 = (Math.PI*b/180);

    // Haversine formula
    double lat2 = Math.asin( Math.sin(lat1)*Math.cos(d/R) +
                             Math.cos(lat1)*Math.sin(d/R)*Math.cos(brng) );
    double lon2 = lon1 + Math.atan2(Math.sin(brng)*Math.sin(d/R)*Math.cos(lat1),
                                    Math.cos(d/R)-Math.sin(lat1)*Math.sin(lat2));

    lat2 = (lat2*180)/Math.PI;
    lon2 = (lon2*180)/Math.PI;

    // normalize long first
    LatLng ll = normLng(lat2,lon2);

    // normalize lat - could flip poles
    ll = normLat(ll.getLat(),ll.getLng());

    return ll;
}

  /**
   * Returns a normalized Lat rectangle shape for the bounding box
   * If you go over the poles, you need to flip the lng value too
   */
  private static LatLng normLat(double lat, double lng) {
    if (lat > 90.0) {
        lat = 90.0 - (lat - 90.0);
        if (lng < 0) {
                lng = lng+180;
        } else {
                lng=lng-180;
        }
    }
    else if (lat < -90.0) {
        lat = -90.0 - (lat + 90.0);
        if (lng < 0) {
                lng = lng+180;
        } else {
                lng=lng-180;
        }
    }
    LatLng ll=new FloatLatLng(lat, lng);
    return ll;
  }

  /**
   * Returns a normalized Lng rectangle shape for the bounding box
   */
  private static LatLng normLng(double lat,double lng) {
    if (lng > 180.0) {
        lng = -1.0*(180.0 - (lng - 180.0));
    }
    else if (lng < -180.0) {
        lng = (lng + 180.0)+180.0;
    }
    LatLng ll=new FloatLatLng(lat, lng);
    return ll;
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((ll == null) ? 0 : ll.hashCode());
    result = prime * result + ((ur == null) ? 0 : ur.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;
    LLRect other = (LLRect) obj;
    if (ll == null) {
      if (other.ll != null)
        return false;
    } else if (!ll.equals(other.ll))
      return false;
    if (ur == null) {
      if (other.ur != null)
        return false;
    } else if (!ur.equals(other.ur))
      return false;
    return true;
  }
  
  
}