/*
* 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;
/**
* Represents an edge in Graph. An edge is an arc in a graph which
* connects exactly two nodes. These two nodes are referred to as
* the A node and the B node of the edge. The order of the A node and the B node
* is refered to as the <B>node orientation</B> of the edge.
*
* @see Node
* @see Graph
*
* @author Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net
*
*
* @source $URL$
*/
public interface Edge extends Graphable {
/** flag to indicate equal node orientation of two edges **/
public static final int EQUAL_NODE_ORIENTATION = 0;
/** flag to indicate unequal node orientation of two edges **/
public static final int UNEQUAL_NODE_ORIENTATION = 1;
/** flag to indicate opposite node orientation of two edges **/
public static final int OPPOSITE_NODE_ORIENTATION = -1;
/**
* Returns the A node of the edge.
*
* @return The A node.
*/
public Node getNodeA();
/**
* Returns the B node of the edge.
*
* @return The B node.
*/
public Node getNodeB();
/**
* Returns one of the two nodes of an edge. If the specified node is node A,
* then node B is returned, and vice versa.
*
* @param node The node opposite of the node to return.
*
* @return Node A if node B is specified, node B if node A is specified.
*/
public Node getOtherNode(Node node);
/**
* Reverses the node orientation of the edge.
*/
public void reverse();
/**
* Compares the node orientation of the edge with another edge.
*
* @return EQUAL_NODE_ORIENTATION : both nodes are equal in the correct order.
* UNEQUAL_NODE_ORIENTATION: both nodes are not equal
* OPPOSITE_NODE_ORIENTATION : both nodes are equal in opposite order.
*/
public int compareNodes(Edge other);
}