Class PointPairDistance

1	/*
2	* Copyright (c) 2016 Vivid Solutions.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12	package org.locationtech.jts.operation.buffer.validate;
13
14	import org.locationtech.jts.geom.Coordinate;
15
16	/**
17	* Contains a pair of points and the distance between them.
18	* Provides methods to update with a new point pair with
19	* either maximum or minimum distance.
20	*/
21	public class PointPairDistance {
22
23	private Coordinate[] pt = { new Coordinate(), new Coordinate() };
24	private double distance = Double.NaN;
25	private boolean isNull = true;
26
27	public PointPairDistance()
28	{
29	}
30
31	public void initialize() { isNull = true; }
32
33	public void initialize(Coordinate p0, Coordinate p1)
34	{
35	pt[0].setCoordinate(p0);
36	pt[1].setCoordinate(p1);
37	distance = p0.distance(p1);
38	isNull = false;
39	}
40
41	/**
42	* Initializes the points, avoiding recomputing the distance.
43	* @param p0
44	* @param p1
45	* @param distance the distance between p0 and p1
46	*/
47	private void initialize(Coordinate p0, Coordinate p1, double distance)
48	{
49	pt[0].setCoordinate(p0);
50	pt[1].setCoordinate(p1);
51	this.distance = distance;
52	isNull = false;
53	}
54
55	public double getDistance() { return distance; }
56
57	public Coordinate[] getCoordinates() { return pt; }
58
59	public Coordinate getCoordinate(int i) { return pt[i]; }
60
61	public void setMaximum(PointPairDistance ptDist)
62	{
63	setMaximum(ptDist.pt[0], ptDist.pt[1]);
64	}
65
66	public void setMaximum(Coordinate p0, Coordinate p1)
67	{
68	if (isNull) {
69	initialize(p0, p1);
70	return;
71	}
72	double dist = p0.distance(p1);
73	if (dist > distance)
74	initialize(p0, p1, dist);
75	}
76
77	public void setMinimum(PointPairDistance ptDist)
78	{
79	setMinimum(ptDist.pt[0], ptDist.pt[1]);
80	}
81
82	public void setMinimum(Coordinate p0, Coordinate p1)
83	{
84	if (isNull) {
85	initialize(p0, p1);
86	return;
87	}
88	double dist = p0.distance(p1);
89	if (dist < distance)
90	initialize(p0, p1, dist);
91	}
92	}
93