Class EdgeString

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.operation.linemerge;
14
15
16	import java.util.ArrayList;
17	import java.util.Iterator;
18	import java.util.List;
19
20	import org.locationtech.jts.geom.Coordinate;
21	import org.locationtech.jts.geom.CoordinateArrays;
22	import org.locationtech.jts.geom.CoordinateList;
23	import org.locationtech.jts.geom.GeometryFactory;
24	import org.locationtech.jts.geom.LineString;
25
26	/**
27	* A sequence of {@link LineMergeDirectedEdge}s forming one of the lines that will
28	* be output by the line-merging process.
29	*
30	* @version 1.7
31	*/
32	public class EdgeString {
33	private GeometryFactory factory;
34	private List directedEdges = new ArrayList();
35	private Coordinate[] coordinates = null;
36	/**
37	* Constructs an EdgeString with the given factory used to convert this EdgeString
38	* to a LineString
39	*/
40	public EdgeString(GeometryFactory factory) {
41	this.factory = factory;
42	}
43
44	/**
45	* Adds a directed edge which is known to form part of this line.
46	*/
47	public void add(LineMergeDirectedEdge directedEdge) {
48	directedEdges.add(directedEdge);
49	}
50
51	private Coordinate[] getCoordinates() {
52	if (coordinates == null) {
53	int forwardDirectedEdges = 0;
54	int reverseDirectedEdges = 0;
55	CoordinateList coordinateList = new CoordinateList();
56	for (Iterator i = directedEdges.iterator(); i.hasNext();) {
57	LineMergeDirectedEdge directedEdge = (LineMergeDirectedEdge) i.next();
58	if (directedEdge.getEdgeDirection()) {
59	forwardDirectedEdges++;
60	}
61	else {
62	reverseDirectedEdges++;
63	}
64	coordinateList.add(((LineMergeEdge) directedEdge.getEdge()).getLine()
65	.getCoordinates(), false,
66	directedEdge.getEdgeDirection());
67	}
68	coordinates = coordinateList.toCoordinateArray();
69	if (reverseDirectedEdges > forwardDirectedEdges) {
70	CoordinateArrays.reverse(coordinates);
71	}
72	}
73
74	return coordinates;
75	}
76
77	/**
78	* Converts this EdgeString into a LineString.
79	*/
80	public LineString toLineString() {
81	return factory.createLineString(getCoordinates());
82	}
83	}
84