EdgeEndBundle.java
/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.operation.relate;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.locationtech.jts.algorithm.BoundaryNodeRule;
import org.locationtech.jts.geom.IntersectionMatrix;
import org.locationtech.jts.geom.Location;
import org.locationtech.jts.geom.Position;
import org.locationtech.jts.geomgraph.Edge;
import org.locationtech.jts.geomgraph.EdgeEnd;
import org.locationtech.jts.geomgraph.GeometryGraph;
import org.locationtech.jts.geomgraph.Label;
/**
* A collection of {@link EdgeEnd}s which obey the following invariant:
* They originate at the same node and have the same direction.
*
* @version 1.7
*/
public class EdgeEndBundle
extends EdgeEnd
{
// private BoundaryNodeRule boundaryNodeRule;
private List edgeEnds = new ArrayList();
public EdgeEndBundle(BoundaryNodeRule boundaryNodeRule, EdgeEnd e)
{
super(e.getEdge(), e.getCoordinate(), e.getDirectedCoordinate(), new Label(e.getLabel()));
insert(e);
/*
if (boundaryNodeRule != null)
this.boundaryNodeRule = boundaryNodeRule;
else
boundaryNodeRule = BoundaryNodeRule.OGC_SFS_BOUNDARY_RULE;
*/
}
public EdgeEndBundle(EdgeEnd e)
{
this(null, e);
}
public Label getLabel() { return label; }
public Iterator iterator() { return edgeEnds.iterator(); }
public List getEdgeEnds() { return edgeEnds; }
public void insert(EdgeEnd e)
{
// Assert: start point is the same
// Assert: direction is the same
edgeEnds.add(e);
}
/**
* This computes the overall edge label for the set of
* edges in this EdgeStubBundle. It essentially merges
* the ON and side labels for each edge. These labels must be compatible
*/
public void computeLabel(BoundaryNodeRule boundaryNodeRule)
{
// create the label. If any of the edges belong to areas,
// the label must be an area label
boolean isArea = false;
for (Iterator it = iterator(); it.hasNext(); ) {
EdgeEnd e = (EdgeEnd) it.next();
if (e.getLabel().isArea()) isArea = true;
}
if (isArea)
label = new Label(Location.NONE, Location.NONE, Location.NONE);
else
label = new Label(Location.NONE);
// compute the On label, and the side labels if present
for (int i = 0; i < 2; i++) {
computeLabelOn(i, boundaryNodeRule);
if (isArea)
computeLabelSides(i);
}
}
/**
* Compute the overall ON location for the list of EdgeStubs.
* (This is essentially equivalent to computing the self-overlay of a single Geometry)
* edgeStubs can be either on the boundary (e.g. Polygon edge)
* OR in the interior (e.g. segment of a LineString)
* of their parent Geometry.
* In addition, GeometryCollections use a {@link BoundaryNodeRule} to determine
* whether a segment is on the boundary or not.
* Finally, in GeometryCollections it can occur that an edge is both
* on the boundary and in the interior (e.g. a LineString segment lying on
* top of a Polygon edge.) In this case the Boundary is given precedence.
* <br>
* These observations result in the following rules for computing the ON location:
* <ul>
* <li> if there are an odd number of Bdy edges, the attribute is Bdy
* <li> if there are an even number >= 2 of Bdy edges, the attribute is Int
* <li> if there are any Int edges, the attribute is Int
* <li> otherwise, the attribute is NULL.
* </ul>
*/
private void computeLabelOn(int geomIndex, BoundaryNodeRule boundaryNodeRule)
{
// compute the ON location value
int boundaryCount = 0;
boolean foundInterior = false;
for (Iterator it = iterator(); it.hasNext(); ) {
EdgeEnd e = (EdgeEnd) it.next();
int loc = e.getLabel().getLocation(geomIndex);
if (loc == Location.BOUNDARY) boundaryCount++;
if (loc == Location.INTERIOR) foundInterior = true;
}
int loc = Location.NONE;
if (foundInterior) loc = Location.INTERIOR;
if (boundaryCount > 0) {
loc = GeometryGraph.determineBoundary(boundaryNodeRule, boundaryCount);
}
label.setLocation(geomIndex, loc);
}
/**
* Compute the labelling for each side
*/
private void computeLabelSides(int geomIndex)
{
computeLabelSide(geomIndex, Position.LEFT);
computeLabelSide(geomIndex, Position.RIGHT);
}
/**
* To compute the summary label for a side, the algorithm is:
* FOR all edges
* IF any edge's location is INTERIOR for the side, side location = INTERIOR
* ELSE IF there is at least one EXTERIOR attribute, side location = EXTERIOR
* ELSE side location = NULL
* <br>
* Note that it is possible for two sides to have apparently contradictory information
* i.e. one edge side may indicate that it is in the interior of a geometry, while
* another edge side may indicate the exterior of the same geometry. This is
* not an incompatibility - GeometryCollections may contain two Polygons that touch
* along an edge. This is the reason for Interior-primacy rule above - it
* results in the summary label having the Geometry interior on <b>both</b> sides.
*/
private void computeLabelSide(int geomIndex, int side)
{
for (Iterator it = iterator(); it.hasNext(); ) {
EdgeEnd e = (EdgeEnd) it.next();
if (e.getLabel().isArea()) {
int loc = e.getLabel().getLocation(geomIndex, side);
if (loc == Location.INTERIOR) {
label.setLocation(geomIndex, side, Location.INTERIOR);
return;
}
else if (loc == Location.EXTERIOR)
label.setLocation(geomIndex, side, Location.EXTERIOR);
}
}
}
/**
* Update the IM with the contribution for the computed label for the EdgeStubs.
*/
void updateIM(IntersectionMatrix im)
{
Edge.updateIM(label, im);
}
public void print(PrintStream out)
{
out.println("EdgeEndBundle--> Label: " + label);
for (Iterator it = iterator(); it.hasNext(); ) {
EdgeEnd ee = (EdgeEnd) it.next();
ee.print(out);
out.println();
}
}
}