} // ensure non-instantiability.
public static IList findPathBetween(Graph graph, Object startVertex,
Object endVertex)
{
MyBreadthFirstIterator iter = new MyBreadthFirstIterator(graph, startVertex);
while (iter.MoveNext())
{
object vertex = iter.Current;
if (vertex.Equals(endVertex))
{
return(createPath(iter, endVertex));
}
}
return(null);
}
private BFSShortestPath() { } // ensure non-instantiability.
public static IList findPathBetween(Graph graph, Object startVertex,
Object endVertex)
{
MyBreadthFirstIterator iter = new MyBreadthFirstIterator(graph, startVertex);
while (iter.MoveNext())
{
object vertex = iter.Current;
if (vertex.Equals(endVertex))
{
return createPath(iter, endVertex);
}
}
return null;
}
private static IList createPath(MyBreadthFirstIterator iter, Object endVertex)
{
ArrayList path = new ArrayList();
while (true)
{
Edge edge = iter.getSpanningTreeEdge(endVertex);
if (edge == null)
{
break;
}
path.Add(edge);
endVertex = edge.oppositeVertex(endVertex);
}
path.Reverse();
return(path);
}
private static IList createPath(MyBreadthFirstIterator iter, Object endVertex)
{
ArrayList path = new ArrayList();
while(true)
{
Edge edge = iter.getSpanningTreeEdge(endVertex);
if(edge == null)
{
break;
}
path.Add(edge);
endVertex = edge.oppositeVertex( endVertex );
}
path.Reverse();
return path;
}
private void createShortestPathGraph()
{
/* shortestPathGraph = new DefaultDirectedGraph();
* //shortestPathGraph.addAllVertices(g.vertexSet());
*
* LinkedList queue = new LinkedList();
*
* //encounter target vertex
* queue.addLast(targetVertex);
* shortestPathGraph.addVertex(targetVertex);
*
* int distance = 0;
*
* Object firstVertexOfNextLevel = targetVertex;
* Collection verticesOfNextLevel = new ArrayList();
*
* while (!queue.isEmpty()) {
* //provide next vertex
* Object vertex = queue.removeFirst();
*
* if (vertex == firstVertexOfNextLevel) {
* distance++;
* firstVertexOfNextLevel = null;
* verticesOfNextLevel.clear();
* }
*
* //add unseen children of next vertex
* List edges = g.edgesOf(vertex);
*
* for(Iterator i = edges.iterator(); i.hasNext();) {
* Edge e = (Edge) i.next( );
* Object opposite = e.oppositeVertex(vertex);
*
* if (!shortestPathGraph.containsVertex(opposite)) {
* //encounter vertex
* queue.addLast(opposite);
* shortestPathGraph.addVertex(opposite);
*
* verticesOfNextLevel.add(opposite);
*
* if (firstVertexOfNextLevel == null) {
* firstVertexOfNextLevel = opposite;
* }
* }
*
*
* if (verticesOfNextLevel.contains(opposite)) {
* shortestPathGraph.addEdge(opposite, vertex);
* }
* }
* }*/
shortestPathGraph = new DefaultDirectedGraph();
shortestPathGraph.addVertex(targetVertex);
// This map gives the distance of a vertex to the target vertex
//UPGRADE_TODO: Class 'java.util.HashMap' was converted to 'System.Collections.Hashtable' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilHashMap'"
System.Collections.IDictionary distanceMap = new System.Collections.Hashtable();
for (MyBreadthFirstIterator iter = new MyBreadthFirstIterator(g, targetVertex); iter.MoveNext();)
{
System.Object vertex = iter.Current;
shortestPathGraph.addVertex(vertex);
int distance = iter.level;
distanceMap[vertex] = (System.Int32)distance;
//UPGRADE_TODO: Method 'java.util.Iterator.hasNext' was converted to 'System.Collections.IEnumerator.MoveNext' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilIteratorhasNext'"
for (System.Collections.IEnumerator edges = g.edgesOf(vertex).GetEnumerator(); edges.MoveNext();)
{
//UPGRADE_TODO: Method 'java.util.Iterator.next' was converted to 'System.Collections.IEnumerator.Current' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilIteratornext'"
Edge edge = (Edge)edges.Current;
System.Object opposite = edge.oppositeVertex(vertex);
if (distanceMap[opposite] != null)
{
if (((System.Int32)distanceMap[opposite]) + 1 == distance)
{
shortestPathGraph.addVertex(opposite);
shortestPathGraph.addEdge(vertex, opposite);
}
}
}
if (vertex == sourceVertex)
{
break;
}
}
System.Collections.IEnumerator edgeIterator = shortestPathGraph.outgoingEdgesOf(sourceVertex).GetEnumerator();
edgeIteratorStack = new System.Collections.ArrayList();
edgeIteratorStack.Add(edgeIterator);
vertexStack = new System.Collections.ArrayList();
vertexStack.Add(sourceVertex);
}