com.vividsolutions.jts.geomgraph.Node Maven / Gradle / Ivy
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/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.geomgraph;
import java.io.PrintStream;
import java.util.*;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.IntersectionMatrix;
import com.vividsolutions.jts.geom.Location;
import com.vividsolutions.jts.geomgraph.GraphComponent;
import com.vividsolutions.jts.geomgraph.Label;
import com.vividsolutions.jts.util.*;
/**
* @version 1.7
*/
public class Node
extends GraphComponent
{
protected Coordinate coord; // only non-null if this node is precise
protected EdgeEndStar edges;
public Node(Coordinate coord, EdgeEndStar edges)
{
this.coord = coord;
this.edges = edges;
label = new Label(0, Location.NONE);
}
public Coordinate getCoordinate() { return coord; }
public EdgeEndStar getEdges() { return edges; }
/**
* Tests whether any incident edge is flagged as
* being in the result.
* This test can be used to determine if the node is in the result,
* since if any incident edge is in the result, the node must be in the result as well.
*
* @return true if any indicident edge in the in the result
*/
public boolean isIncidentEdgeInResult()
{
for (Iterator it = getEdges().getEdges().iterator(); it.hasNext(); ) {
DirectedEdge de = (DirectedEdge) it.next();
if (de.getEdge().isInResult())
return true;
}
return false;
}
public boolean isIsolated()
{
return (label.getGeometryCount() == 1);
}
/**
* Basic nodes do not compute IMs
*/
protected void computeIM(IntersectionMatrix im) {}
/**
* Add the edge to the list of edges at this node
*/
public void add(EdgeEnd e)
{
// Assert: start pt of e is equal to node point
edges.insert(e);
e.setNode(this);
}
public void mergeLabel(Node n)
{
mergeLabel(n.label);
}
/**
* To merge labels for two nodes,
* the merged location for each LabelElement is computed.
* The location for the corresponding node LabelElement is set to the result,
* as long as the location is non-null.
*/
public void mergeLabel(Label label2)
{
for (int i = 0; i < 2; i++) {
int loc = computeMergedLocation(label2, i);
int thisLoc = label.getLocation(i);
if (thisLoc == Location.NONE) label.setLocation(i, loc);
}
}
public void setLabel(int argIndex, int onLocation)
{
if (label == null) {
label = new Label(argIndex, onLocation);
}
else
label.setLocation(argIndex, onLocation);
}
/**
* Updates the label of a node to BOUNDARY,
* obeying the mod-2 boundaryDetermination rule.
*/
public void setLabelBoundary(int argIndex)
{
if (label == null) return;
// determine the current location for the point (if any)
int loc = Location.NONE;
if (label != null)
loc = label.getLocation(argIndex);
// flip the loc
int newLoc;
switch (loc) {
case Location.BOUNDARY: newLoc = Location.INTERIOR; break;
case Location.INTERIOR: newLoc = Location.BOUNDARY; break;
default: newLoc = Location.BOUNDARY; break;
}
label.setLocation(argIndex, newLoc);
}
/**
* The location for a given eltIndex for a node will be one
* of { null, INTERIOR, BOUNDARY }.
* A node may be on both the boundary and the interior of a geometry;
* in this case, the rule is that the node is considered to be in the boundary.
* The merged location is the maximum of the two input values.
*/
int computeMergedLocation(Label label2, int eltIndex)
{
int loc = Location.NONE;
loc = label.getLocation(eltIndex);
if (! label2.isNull(eltIndex)) {
int nLoc = label2.getLocation(eltIndex);
if (loc != Location.BOUNDARY) loc = nLoc;
}
return loc;
}
public void print(PrintStream out)
{
out.println("node " + coord + " lbl: " + label);
}
}