Class Point

1
2
3	/*
4	* Copyright (c) 2016 Vivid Solutions.
5	*
6	* All rights reserved. This program and the accompanying materials
7	* are made available under the terms of the Eclipse Public License 2.0
8	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
9	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
10	* and the Eclipse Distribution License is available at
11	*
12	* http://www.eclipse.org/org/documents/edl-v10.php.
13	*/
14	package org.locationtech.jts.geom;
15
16	import org.locationtech.jts.util.Assert;
17
18	/**
19	* Represents a single point.
20	*
21	* A <code>Point</code> is topologically valid if and only if:
22	* <ul>
23	* <li>the coordinate which defines it (if any) is a valid coordinate
24	* (i.e. does not have an <code>NaN</code> X or Y ordinate)
25	* </ul>
26	*
27	*@version 1.7
28	*/
29	public class Point
30	extends Geometry
31	implements Puntal
32	{
33	private static final long serialVersionUID = 4902022702746614570L;
34	/**
35	* The <code>Coordinate</code> wrapped by this <code>Point</code>.
36	*/
37	private CoordinateSequence coordinates;
38
39	/**
40	* Constructs a <code>Point</code> with the given coordinate.
41	*
42	*@param coordinate the coordinate on which to base this <code>Point</code>
43	* , or <code>null</code> to create the empty geometry.
44	*@param precisionModel the specification of the grid of allowable points
45	* for this <code>Point</code>
46	*@param SRID the ID of the Spatial Reference System used by this
47	* <code>Point</code>
48	* @deprecated Use GeometryFactory instead
49	*/
50	public Point(Coordinate coordinate, PrecisionModel precisionModel, int SRID) {
51	super(new GeometryFactory(precisionModel, SRID));
52	init(getFactory().getCoordinateSequenceFactory().create(
53	coordinate != null ? new Coordinate[]{coordinate} : new Coordinate[]{}));
54	}
55
56	/**
57	*@param coordinates contains the single coordinate on which to base this <code>Point</code>
58	* , or <code>null</code> to create the empty geometry.
59	*/
60	public Point(CoordinateSequence coordinates, GeometryFactory factory) {
61	super(factory);
62	init(coordinates);
63	}
64
65	private void init(CoordinateSequence coordinates)
66	{
67	if (coordinates == null) {
68	coordinates = getFactory().getCoordinateSequenceFactory().create(new Coordinate[]{});
69	}
70	Assert.isTrue(coordinates.size() <= 1);
71	this.coordinates = coordinates;
72	}
73
74	public Coordinate[] getCoordinates() {
75	return isEmpty() ? new Coordinate[]{} : new Coordinate[]{
76	getCoordinate()
77	};
78	}
79
80	public int getNumPoints() {
81	return isEmpty() ? 0 : 1;
82	}
83
84	public boolean isEmpty() {
85	return coordinates.size() == 0;
86	}
87
88	public boolean isSimple() {
89	return true;
90	}
91
92	public int getDimension() {
93	return 0;
94	}
95
96	public int getBoundaryDimension() {
97	return Dimension.FALSE;
98	}
99
100	public double getX() {
101	if (getCoordinate() == null) {
102	throw new IllegalStateException("getX called on empty Point");
103	}
104	return getCoordinate().x;
105	}
106
107	public double getY() {
108	if (getCoordinate() == null) {
109	throw new IllegalStateException("getY called on empty Point");
110	}
111	return getCoordinate().y;
112	}
113
114	public Coordinate getCoordinate() {
115	return coordinates.size() != 0 ? coordinates.getCoordinate(0): null;
116	}
117
118	public String getGeometryType() {
119	return Geometry.TYPENAME_POINT;
120	}
121
122	/**
123	* Gets the boundary of this geometry.
124	* Zero-dimensional geometries have no boundary by definition,
125	* so an empty GeometryCollection is returned.
126	*
127	* @return an empty GeometryCollection
128	* @see Geometry#getBoundary
129	*/
130	public Geometry getBoundary() {
131	return getFactory().createGeometryCollection();
132	}
133
134	protected Envelope computeEnvelopeInternal() {
135	if (isEmpty()) {
136	return new Envelope();
137	}
138	Envelope env = new Envelope();
139	env.expandToInclude(coordinates.getX(0), coordinates.getY(0));
140	return env;
141	}
142
143	public boolean equalsExact(Geometry other, double tolerance) {
144	if (!isEquivalentClass(other)) {
145	return false;
146	}
147	if (isEmpty() && other.isEmpty()) {
148	return true;
149	}
150	if (isEmpty() != other.isEmpty()) {
151	return false;
152	}
153	return equal(((Point) other).getCoordinate(), this.getCoordinate(), tolerance);
154	}
155
156	public void apply(CoordinateFilter filter) {
157	if (isEmpty()) { return; }
158	filter.filter(getCoordinate());
159	}
160
161	public void apply(CoordinateSequenceFilter filter)
162	{
163	if (isEmpty())
164	return;
165	filter.filter(coordinates, 0);
166	if (filter.isGeometryChanged())
167	geometryChanged();
168	}
169
170	public void apply(GeometryFilter filter) {
171	filter.filter(this);
172	}
173
174	public void apply(GeometryComponentFilter filter) {
175	filter.filter(this);
176	}
177
178	/**
179	* Creates and returns a full copy of this {@link Point} object.
180	* (including all coordinates contained by it).
181	*
182	* @return a clone of this instance
183	* @deprecated
184	*/
185	public Object clone() {
186	return copy();
187	}
188
189	protected Point copyInternal() {
190	return new Point(coordinates.copy(), factory);
191	}
192
193	public Point reverse() {
194	return (Point) super.reverse();
195	}
196
197	protected Point reverseInternal()
198	{
199	return getFactory().createPoint(coordinates.copy());
200	}
201
202	public void normalize()
203	{
204	// a Point is always in normalized form
205	}
206
207	protected int compareToSameClass(Object other) {
208	Point point = (Point) other;
209	return getCoordinate().compareTo(point.getCoordinate());
210	}
211
212	protected int compareToSameClass(Object other, CoordinateSequenceComparator comp)
213	{
214	Point point = (Point) other;
215	return comp.compare(this.coordinates, point.coordinates);
216	}
217
218	protected int getTypeCode() {
219	return Geometry.TYPECODE_POINT;
220	}
221
222	public CoordinateSequence getCoordinateSequence() {
223	return coordinates;
224	}
225	}
226
227