Class EdgeGraphBuilder

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
13	package org.locationtech.jts.edgegraph;
14
15	import java.util.Collection;
16	import java.util.Iterator;
17
18	import org.locationtech.jts.geom.CoordinateSequence;
19	import org.locationtech.jts.geom.Geometry;
20	import org.locationtech.jts.geom.GeometryComponentFilter;
21	import org.locationtech.jts.geom.LineString;
22
23
24	/**
25	* Builds an edge graph from geometries containing edges.
26	*
27	* @author mdavis
28	*
29	*/
30	public class EdgeGraphBuilder
31	{
32	public static EdgeGraph build(Collection geoms) {
33	EdgeGraphBuilder builder = new EdgeGraphBuilder();
34	builder.add(geoms);
35	return builder.getGraph();
36	}
37
38	private EdgeGraph graph = new EdgeGraph();
39
40	public EdgeGraphBuilder()
41	{
42
43	}
44
45	public EdgeGraph getGraph()
46	{
47	return graph;
48	}
49
50	/**
51	* Adds the edges of a Geometry to the graph.
52	* May be called multiple times.
53	* Any dimension of Geometry may be added; the constituent edges are
54	* extracted.
55	*
56	* @param geometry geometry to be added
57	*/
58	public void add(Geometry geometry) {
59	geometry.apply(new GeometryComponentFilter() {
60	public void filter(Geometry component) {
61	if (component instanceof LineString) {
62	add((LineString)component);
63	}
64	}
65	});
66	}
67	/**
68	* Adds the edges in a collection of {@link Geometry}s to the graph.
69	* May be called multiple times.
70	* Any dimension of Geometry may be added.
71	*
72	* @param geometries the geometries to be added
73	*/
74	public void add(Collection geometries)
75	{
76	for (Iterator i = geometries.iterator(); i.hasNext(); ) {
77	Geometry geometry = (Geometry) i.next();
78	add(geometry);
79	}
80	}
81
82	private void add(LineString lineString) {
83	CoordinateSequence seq = lineString.getCoordinateSequence();
84	for (int i = 1; i < seq.size(); i++) {
85	graph.addEdge(seq.getCoordinate(i-1), seq.getCoordinate(i));
86	}
87	}
88
89
90	}
91