/*
* 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.traverse.standard;
import org.geotools.graph.structure.Graph;
import org.geotools.graph.util.Queue;
import org.geotools.graph.util.Stack;
/**
* Iterates over the nodes of a graph in a <B>Depth First Search</B> pattern
* starting from a specified node. The following illustrates the iteration order.
* <BR>
* <BR>
* <IMG src="doc-files/dfs.gif"/><BR>
* <BR>
* The iteration operates by maintaning a node queue of <B>active</B> nodes.
* An <B>active</B> node is a node that will returned at a later stage of the i
* teration. The node queue for a Depth First iteration is implemented as a
* <B>Last In First Out</B> queue (a Stack).
* A node is placed in the the node queue if it has not been visited, and
* it is adjacent to a a node that has been visited. The node queue intially
* contains only the source node of the traversal.
*
* @author Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net
*
*
*
* @source $URL$
*/
public class DepthFirstIterator extends BreadthFirstIterator {
/**
* Builds the node queue for the Iteration.
*
* @param graph The graph of the iteration.
*
* @return A Last In First Out queue (Stack)
*/
protected Queue buildQueue(Graph graph) {
return(new Stack(graph.getNodes().size()));
}
}