/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2001-2006 Vivid Solutions
* (C) 2001-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.geometry.iso.topograph2D;
import java.io.PrintStream;
import java.util.Iterator;
/**
* A node in a {@link PlanarGraph}is a location where 0 or more {@link Edge}s
* meet. A node is connected to each of its incident Edges via an outgoing
* DirectedEdge.
*
*
* @source $URL$
*/
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 <code>true</code> 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) {
// 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);
}
}