Class PointExtracter

1
2	/*
3	* Copyright (c) 2016 Vivid Solutions.
4	*
5	* All rights reserved. This program and the accompanying materials
6	* are made available under the terms of the Eclipse Public License 2.0
7	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
8	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
9	* and the Eclipse Distribution License is available at
10	*
11	* http://www.eclipse.org/org/documents/edl-v10.php.
12	*/
13	package org.locationtech.jts.geom.util;
14
15	import java.util.ArrayList;
16	import java.util.Collections;
17	import java.util.List;
18
19	import org.locationtech.jts.geom.Geometry;
20	import org.locationtech.jts.geom.GeometryCollection;
21	import org.locationtech.jts.geom.GeometryFilter;
22	import org.locationtech.jts.geom.Point;
23
24
25	/**
26	* Extracts all the 0-dimensional ({@link Point}) components from a {@link Geometry}.
27	*
28	* @version 1.7
29	* @see GeometryExtracter
30	*/
31	public class PointExtracter
32	implements GeometryFilter
33	{
34	/**
35	* Extracts the {@link Point} elements from a single {@link Geometry}
36	* and adds them to the provided {@link List}.
37	*
38	* @param geom the geometry from which to extract
39	* @param list the list to add the extracted elements to
40	*/
41	public static List getPoints(Geometry geom, List list)
42	{
43	if (geom instanceof Point) {
44	list.add(geom);
45	}
46	else if (geom instanceof GeometryCollection) {
47	geom.apply(new PointExtracter(list));
48	}
49	// skip non-Polygonal elemental geometries
50
51	return list;
52	}
53
54	/**
55	* Extracts the {@link Point} elements from a single {@link Geometry}
56	* and returns them in a {@link List}.
57	*
58	* @param geom the geometry from which to extract
59	*/
60	public static List getPoints(Geometry geom) {
61	if (geom instanceof Point) {
62	return Collections.singletonList(geom);
63	}
64	return getPoints(geom, new ArrayList());
65	}
66
67	private List pts;
68	/**
69	* Constructs a PointExtracterFilter with a list in which to store Points found.
70	*/
71	public PointExtracter(List pts)
72	{
73	this.pts = pts;
74	}
75
76	public void filter(Geometry geom)
77	{
78	if (geom instanceof Point) pts.add(geom);
79	}
80
81	}
82