/*
* 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.planargraph;
import java.util.*;
import com.vividsolutions.jts.geom.Coordinate;
/**
* 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. Some clients using a <code>PlanarGraph</code> may want to
* subclass <code>Node</code> to add their own application-specific
* data and methods.
*
* @version 1.7
*/
public class Node
extends GraphComponent
{
/**
* Returns all Edges that connect the two nodes (which are assumed to be different).
*/
public static Collection getEdgesBetween(Node node0, Node node1)
{
List edges0 = DirectedEdge.toEdges(node0.getOutEdges().getEdges());
Set commonEdges = new HashSet(edges0);
List edges1 = DirectedEdge.toEdges(node1.getOutEdges().getEdges());
commonEdges.retainAll(edges1);
return commonEdges;
}
/** The location of this Node */
protected Coordinate pt;
/** The collection of DirectedEdges that leave this Node */
protected DirectedEdgeStar deStar;
/**
* Constructs a Node with the given location.
*/
public Node(Coordinate pt)
{
this(pt, new DirectedEdgeStar());
}
/**
* Constructs a Node with the given location and collection of outgoing DirectedEdges.
*/
public Node(Coordinate pt, DirectedEdgeStar deStar)
{
this.pt = pt;
this.deStar = deStar;
}
/**
* Returns the location of this Node.
*/
public Coordinate getCoordinate() { return pt; }
/**
* Adds an outgoing DirectedEdge to this Node.
*/
public void addOutEdge(DirectedEdge de)
{
deStar.add(de);
}
/**
* Returns the collection of DirectedEdges that leave this Node.
*/
public DirectedEdgeStar getOutEdges() { return deStar; }
/**
* Returns the number of edges around this Node.
*/
public int getDegree() { return deStar.getDegree(); }
/**
* Returns the zero-based index of the given Edge, after sorting in ascending order
* by angle with the positive x-axis.
*/
public int getIndex(Edge edge)
{
return deStar.getIndex(edge);
}
/**
* Removes a {@link DirectedEdge} incident on this node.
* Does not change the state of the directed edge.
*/
public void remove(DirectedEdge de)
{
deStar.remove(de);
}
/**
* Removes this node from its containing graph.
*/
void remove() {
pt = null;
}
/**
* Tests whether this node has been removed from its containing graph
*
* @return <code>true</code> if this node is removed
*/
public boolean isRemoved()
{
return pt == null;
}
}