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yacy_search_server/source/de/anomic/data/Coordinates.java

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// Coordinates.java
// (C) 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 04.10.2009 on http://yacy.net
//
// This is a part of YaCy
//
// $LastChangedDate: 2006-04-02 22:40:07 +0200 (So, 02 Apr 2006) $
// $LastChangedRevision: 1986 $
// $LastChangedBy: orbiter $
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package de.anomic.data;
public class Coordinates implements Comparable<Coordinates> {
private static final double tenmeter = 90.0 / 1.0e6;
private double lon, lat;
public Coordinates(double lon, double lat) {
this.lon = lon;
this.lat = lat;
}
public double lon() {
return this.lon;
}
public double lat() {
return this.lat;
}
private static final double bits30 = new Double(1L << 30).doubleValue(); // this is about one billion (US)
private static final double upscale = bits30 / 360.0;
private static final int coord2int(double coord) {
return (int) ((coord + 180.0) * upscale);
}
/**
* compute the hash code of a coordinate
* this produces identical hash codes for locations that are close to each other
*/
public int hashCode() {
int lon1 = coord2int(this.lon) >> 15;
int lat1 = coord2int(this.lat) >> 15;
int h = (lon1 << 15) + lat1;
//System.out.println("lon=" + this.lon + ", lat=" + this.lat + ", hash=" + h);
return h;
}
/**
* comparator that is needed to use the class inside TreeMap/TreeSet
*/
public int compareTo(Coordinates o) {
if (this.equals(o)) return 0;
int s = this.hashCode();
int t = o.hashCode();
if (s > t) return 1;
if (s < t) return -1;
return 0;
}
/**
* equality test that is needed to use the class inside HashMap/HashSet
*/
public boolean equals(Object o) {
if (!(o instanceof Coordinates)) return false;
Coordinates oo = (Coordinates) o;
if (this.lon == oo.lon && this.lat == oo.lat) return true;
// we access fuzzy values that are considered as equal if they are close to each other
return Math.abs(this.lon - oo.lon) < tenmeter && Math.abs(this.lat - oo.lat) < tenmeter;
}
public String toString() {
return "[" + this.lon + "," + this.lat + "]";
}
}