/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, 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.graph.structure.basic;
import java.util.ArrayList;
import java.util.Iterator;
import org.geotools.graph.structure.Edge;
import org.geotools.graph.structure.Node;
/**
* Basic implementation of Edge.
*
* @author Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net
*
*
*
* @source $URL$
*/
public class BasicEdge extends BasicGraphable implements Edge {
/** A node */
private Node m_nodeA;
/** B node */
private Node m_nodeB;
/**
* Constructs a new edge.
*
* @param nodeA A node of edge.
* @param nodeB B node of edge.
*/
public BasicEdge(Node nodeA, Node nodeB) {
super();
m_nodeA = nodeA;
m_nodeB = nodeB;
}
/**
* @see Edge#getNodeA()
*/
public Node getNodeA() {
return(m_nodeA);
}
/**
* @see Edge#getNodeB()
*/
public Node getNodeB() {
return(m_nodeB);
}
/**
* Returns null if the specified node is neither the A node or the B node.
*
* @see Edge#getOtherNode(Node)
*/
public Node getOtherNode(Node node) {
if (node.equals(m_nodeA)) return(m_nodeB);
if (node.equals(m_nodeB)) return(m_nodeA);
return(null);
}
/**
* Returns all edges that are adjacent to both the A and B nodes. This
* iterator is generated by calculating an underlying collection upon each
* method call.
*
* @see org.geotools.graph.structure.Graphable#getRelated()
*/
public Iterator getRelated() {
ArrayList adj = new ArrayList();
for (Iterator itr = m_nodeA.getEdges().iterator(); itr.hasNext();) {
Edge e = (Edge)itr.next();
switch(e.compareNodes(this)) {
case EQUAL_NODE_ORIENTATION: //same node orientation
if (e.equals(this)) continue;
case OPPOSITE_NODE_ORIENTATION: //opposite node orientation
case UNEQUAL_NODE_ORIENTATION: //different
adj.add(e);
}
}
for (Iterator itr = m_nodeB.getEdges().iterator(); itr.hasNext();) {
Edge e = (Edge)itr.next();
switch(e.compareNodes(this)) {
case EQUAL_NODE_ORIENTATION:
case OPPOSITE_NODE_ORIENTATION:
continue; //edges already added from other node
case UNEQUAL_NODE_ORIENTATION:
adj.add(e);
}
}
return(adj.iterator());
}
/**
* @see Edge#reverse()
*/
public void reverse() {
Node n = m_nodeA;
m_nodeA = m_nodeB;
m_nodeB = n;
}
/**
* @see Edge#compareNodes(Edge)
*/
public int compareNodes(Edge other) {
if(m_nodeA.equals(other.getNodeA()) && m_nodeB.equals(other.getNodeB()))
return(EQUAL_NODE_ORIENTATION);
if(
(m_nodeA.equals(other.getNodeA()) && m_nodeB.equals(other.getNodeB()))||
(m_nodeA.equals(other.getNodeB()) && m_nodeB.equals(other.getNodeA()))
) return(OPPOSITE_NODE_ORIENTATION);
return(UNEQUAL_NODE_ORIENTATION);
}
/**
* Returns ([A node.toString()],[B node.toString()]).
*/
public String toString() {
return(super.toString()+" ("+m_nodeA.getID()+","+m_nodeB.getID()+")");
}
}