GraphAlgorithmObserver.java

package graph;

import java.util.List;

public interface GraphAlgorithmObserver<V> {
	
	/** Called by the graph to notify this Observer that
	 * a Depth-First-Search has been initiated.
	 */
	public void notifyDFSHasBegun();
	
	/** Called by the graph to notify this Observer that
	 * a Breadth-First Search has been initiated.
	 */
	public void notifyBFSHasBegun();
	
	/** Called by the graph to notify this Observer that
	 * a vertex is being "visited" during either DFS or BFS.
	 * 
	 * @param vertexBeingVisited
	 */
	public void notifyVisit(V vertexBeingVisited);
	
	/** Called by the graph to notify this observer that
	 * the search (either DFS or BFS) is over.
	 */
	public void notifySearchIsOver();
	
	/** Called by the graph to notify this observer that
	 * Dijkstra's algorithm has begun. 
	 */
	public void notifyDijkstraHasBegun();
	
	/** Called by the graph to notify this observer that
	 * a vertex has been added to the "Finished Set"
	 * during Dijkstra's algorithm.  The second parameter
	 * is the "cost" (total weight) of the best path
	 * leading from the starting vertex to the one referenced
	 * by the first parameter.
	 * 
	 * @param vertexAddedToFinishedSet
	 * @param costOfPath
	 */
	public void notifyDijkstraVertexFinished(V vertexAddedToFinishedSet, Integer costOfPath);
	
	/** 
	 * <P>Called by the graph to notify this observer that
	 * Dijkstra's algorithm is over.</P>
	 * 
	 * @param path A list of Vertices that are connected along edges,
	 * beginning with the "starting vertex" and ending with the
	 * "finishing vertex".  This will be the optimal (lowest cost)
	 * path from start to finish.
	 */
	public void notifyDijkstraIsOver(List<V> path);
}