Class EdgeEndBundle

1
2
3
4	/*
5	* Copyright (c) 2016 Vivid Solutions.
6	*
7	* All rights reserved. This program and the accompanying materials
8	* are made available under the terms of the Eclipse Public License 2.0
9	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
10	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
11	* and the Eclipse Distribution License is available at
12	*
13	* http://www.eclipse.org/org/documents/edl-v10.php.
14	*/
15	package org.locationtech.jts.operation.relate;
16
17	import java.io.PrintStream;
18	import java.util.ArrayList;
19	import java.util.Iterator;
20	import java.util.List;
21
22	import org.locationtech.jts.algorithm.BoundaryNodeRule;
23	import org.locationtech.jts.geom.IntersectionMatrix;
24	import org.locationtech.jts.geom.Location;
25	import org.locationtech.jts.geomgraph.Edge;
26	import org.locationtech.jts.geomgraph.EdgeEnd;
27	import org.locationtech.jts.geomgraph.GeometryGraph;
28	import org.locationtech.jts.geomgraph.Label;
29	import org.locationtech.jts.geomgraph.Position;
30
31	/**
32	* A collection of {@link EdgeEnd}s which obey the following invariant:
33	* They originate at the same node and have the same direction.
34	*
35	* @version 1.7
36	*/
37	public class EdgeEndBundle
38	extends EdgeEnd
39	{
40	// private BoundaryNodeRule boundaryNodeRule;
41	private List edgeEnds = new ArrayList();
42
43	public EdgeEndBundle(BoundaryNodeRule boundaryNodeRule, EdgeEnd e)
44	{
45	super(e.getEdge(), e.getCoordinate(), e.getDirectedCoordinate(), new Label(e.getLabel()));
46	insert(e);
47	/*
48	if (boundaryNodeRule != null)
49	this.boundaryNodeRule = boundaryNodeRule;
50	else
51	boundaryNodeRule = BoundaryNodeRule.OGC_SFS_BOUNDARY_RULE;
52	*/
53	}
54
55	public EdgeEndBundle(EdgeEnd e)
56	{
57	this(null, e);
58	}
59
60	public Label getLabel() { return label; }
61	public Iterator iterator() { return edgeEnds.iterator(); }
62	public List getEdgeEnds() { return edgeEnds; }
63
64	public void insert(EdgeEnd e)
65	{
66	// Assert: start point is the same
67	// Assert: direction is the same
68	edgeEnds.add(e);
69	}
70	/**
71	* This computes the overall edge label for the set of
72	* edges in this EdgeStubBundle. It essentially merges
73	* the ON and side labels for each edge. These labels must be compatible
74	*/
75	public void computeLabel(BoundaryNodeRule boundaryNodeRule)
76	{
77	// create the label. If any of the edges belong to areas,
78	// the label must be an area label
79	boolean isArea = false;
80	for (Iterator it = iterator(); it.hasNext(); ) {
81	EdgeEnd e = (EdgeEnd) it.next();
82	if (e.getLabel().isArea()) isArea = true;
83	}
84	if (isArea)
85	label = new Label(Location.NONE, Location.NONE, Location.NONE);
86	else
87	label = new Label(Location.NONE);
88
89	// compute the On label, and the side labels if present
90	for (int i = 0; i < 2; i++) {
91	computeLabelOn(i, boundaryNodeRule);
92	if (isArea)
93	computeLabelSides(i);
94	}
95	}
96
97	/**
98	* Compute the overall ON location for the list of EdgeStubs.
99	* (This is essentially equivalent to computing the self-overlay of a single Geometry)
100	* edgeStubs can be either on the boundary (e.g. Polygon edge)
101	* OR in the interior (e.g. segment of a LineString)
102	* of their parent Geometry.
103	* In addition, GeometryCollections use a {@link BoundaryNodeRule} to determine
104	* whether a segment is on the boundary or not.
105	* Finally, in GeometryCollections it can occur that an edge is both
106	* on the boundary and in the interior (e.g. a LineString segment lying on
107	* top of a Polygon edge.) In this case the Boundary is given precedence.
108	* <br>
109	* These observations result in the following rules for computing the ON location:
110	* <ul>
111	* <li> if there are an odd number of Bdy edges, the attribute is Bdy
112	* <li> if there are an even number >= 2 of Bdy edges, the attribute is Int
113	* <li> if there are any Int edges, the attribute is Int
114	* <li> otherwise, the attribute is NULL.
115	* </ul>
116	*/
117	private void computeLabelOn(int geomIndex, BoundaryNodeRule boundaryNodeRule)
118	{
119	// compute the ON location value
120	int boundaryCount = 0;
121	boolean foundInterior = false;
122
123	for (Iterator it = iterator(); it.hasNext(); ) {
124	EdgeEnd e = (EdgeEnd) it.next();
125	int loc = e.getLabel().getLocation(geomIndex);
126	if (loc == Location.BOUNDARY) boundaryCount++;
127	if (loc == Location.INTERIOR) foundInterior = true;
128	}
129	int loc = Location.NONE;
130	if (foundInterior) loc = Location.INTERIOR;
131	if (boundaryCount > 0) {
132	loc = GeometryGraph.determineBoundary(boundaryNodeRule, boundaryCount);
133	}
134	label.setLocation(geomIndex, loc);
135
136	}
137	/**
138	* Compute the labelling for each side
139	*/
140	private void computeLabelSides(int geomIndex)
141	{
142	computeLabelSide(geomIndex, Position.LEFT);
143	computeLabelSide(geomIndex, Position.RIGHT);
144	}
145
146	/**
147	* To compute the summary label for a side, the algorithm is:
148	* FOR all edges
149	* IF any edge's location is INTERIOR for the side, side location = INTERIOR
150	* ELSE IF there is at least one EXTERIOR attribute, side location = EXTERIOR
151	* ELSE side location = NULL
152	* <br>
153	* Note that it is possible for two sides to have apparently contradictory information
154	* i.e. one edge side may indicate that it is in the interior of a geometry, while
155	* another edge side may indicate the exterior of the same geometry. This is
156	* not an incompatibility - GeometryCollections may contain two Polygons that touch
157	* along an edge. This is the reason for Interior-primacy rule above - it
158	* results in the summary label having the Geometry interior on <b>both</b> sides.
159	*/
160	private void computeLabelSide(int geomIndex, int side)
161	{
162	for (Iterator it = iterator(); it.hasNext(); ) {
163	EdgeEnd e = (EdgeEnd) it.next();
164	if (e.getLabel().isArea()) {
165	int loc = e.getLabel().getLocation(geomIndex, side);
166	if (loc == Location.INTERIOR) {
167	label.setLocation(geomIndex, side, Location.INTERIOR);
168	return;
169	}
170	else if (loc == Location.EXTERIOR)
171	label.setLocation(geomIndex, side, Location.EXTERIOR);
172	}
173	}
174	}
175
176	/**
177	* Update the IM with the contribution for the computed label for the EdgeStubs.
178	*/
179	void updateIM(IntersectionMatrix im)
180	{
181	Edge.updateIM(label, im);
182	}
183	public void print(PrintStream out)
184	{
185	out.println("EdgeEndBundle--> Label: " + label);
186	for (Iterator it = iterator(); it.hasNext(); ) {
187	EdgeEnd ee = (EdgeEnd) it.next();
188	ee.print(out);
189	out.println();
190	}
191	}
192	}
193