/**
* Removes an edge from the graph
* @param e Edge to remove
* @return true if edge was removed, false if it wasn't
*/
public Boolean removeEdge(DjikGraphEdge e)
{
// if the edge doesn't exist in the graph we can't remove it.
if (!edges.Contains(e))
{
return(false);
}
// it does exist. make sure the vertices delete each other as neighbors and remove.
e.disconnectNeighbors();
edges.Remove(e);
return(true);
}
/**
* get the weight of the edge to a neighbor.
* @param target The neighboring vertex
* @return the weight of the edge between this vertex and the neighboring vertex. or 0 otherwise.
*/
public int getEdgeWeighToNeighbor(Vertex target)
{
if (!neighbors.ContainsKey(target))
{
return(0);
}
else
{
DjikGraphEdge e = (DjikGraphEdge)neighbors[target];
return(e.getWeight());
}
}
/**
* Add a new weighted edge to the graph
* @param firstVertexName The first vertex this edge connects
* @param secondVertexName The second vertex this edge connects
* @param weight the weight of the edge
* @return true if edge was added, false otherwise
*/
public Boolean addWeightedEdge(String firstVertexName, String secondVertexName, int weight)
{
// if the vertices don't exist in graph, can't connect them.
if (!vertices.ContainsKey(firstVertexName) || !vertices.ContainsKey(secondVertexName))
{
return(false);
}
// also, don't allow self-loops...
if (firstVertexName.Equals(secondVertexName))
{
return(false);
}
// otherwise we are in the clear. connect the vertices via a new edge and return true.
DjikGraphEdge e = new DjikGraphEdge(vertices[firstVertexName] as Vertex, vertices[secondVertexName] as Vertex, weight);
edges.Add(e);
return(true);
}
/**
* Adds a neighbor
* @param v Neighboring vertex to add
* @param e The edge connecting the vertices
* @return true if succeeded connecting. false otherwise.
*/
public void addNeighbor(Vertex v, DjikGraphEdge e)
{
neighbors.Add(v, e);
}
