salvo.jesus.graph

Class WeightedGraphImpl

java.lang.Object

salvo.jesus.graph.GraphImpl

salvo.jesus.graph.WeightedGraphImpl

All Implemented Interfaces:

Serializable, Graph, WeightedGraph

public class WeightedGraphImpl
extends GraphImpl
implements WeightedGraph

An implementation of the WeightedGraph interface where all edges in the graph have a weight.

See Also:

Serialized Form

Field Summary

Fields inherited from class salvo.jesus.graph.GraphImpl

factory, traversal

Constructor Summary

Constructors

Constructor and Description
WeightedGraphImpl() Creates a new instance of WeightedGraphImpl.

Method Summary

Modifier and Type	Method and Description
WeightedEdge	addEdge(Vertex v1, Vertex v2, double weight) Convenience method to add a WeightedEdge with a specified weight into the WeightedGraph.
Vertex	getClosest(Vertex v) Determines the Vertex that is 'closest' to the Vertex specified.
WeightedGraph	minimumSpanningTree() Determine a minimum spanning tree for the weighted graph.
void	setMinimumSpanningTreeAlgorithm(MinimumSpanningTreeAlgorithm algo) Sets the algorithm used to determine the minimum spanning tree.
void	setShortestPathAlgorithm(ShortestPathAlgorithm algo) Sets the algorithm used to determine the shortest path spanning tree.
WeightedGraph	shortestPath(Vertex vertex) Determine a shortest path spanning tree for the weighted graph.

Methods inherited from class salvo.jesus.graph.GraphImpl

add, addEdge, addEdge, addGraphAddEdgeListener, addGraphAddVertexListener, addGraphRemoveEdgeListener, addGraphRemoveVertexListener, addListener, cloneVertices, containsEdge, containsVertex, forgetConnectedSets, getAdjacentVertices, getAdjacentVertices, getConnectedSet, getConnectedSet, getDegree, getDegree, getEdges, getEdgesCount, getEdgeSet, getGraphFactory, getTraversal, getVertexSet, getVertices, getVerticesCount, getVerticesIterator, isConnected, remove, removeEdge, removeEdges, removeGraphAddEdgeListener, removeGraphAddVertexListener, removeGraphRemoveEdgeListener, removeGraphRemoveVertexListener, removeListener, setGraphFactory, setTraversal, toString, traverse

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface salvo.jesus.graph.Graph

add, addEdge, addEdge, addGraphAddEdgeListener, addGraphAddVertexListener, addGraphRemoveEdgeListener, addGraphRemoveVertexListener, addListener, cloneVertices, getAdjacentVertices, getAdjacentVertices, getConnectedSet, getConnectedSet, getDegree, getDegree, getEdges, getEdgesCount, getEdgeSet, getGraphFactory, getTraversal, getVertexSet, getVertices, getVerticesCount, getVerticesIterator, isConnected, remove, removeEdge, removeEdges, removeGraphAddEdgeListener, removeGraphAddVertexListener, removeGraphRemoveEdgeListener, removeGraphRemoveVertexListener, removeListener, setGraphFactory, setTraversal, traverse

Constructor Detail

WeightedGraphImpl

public WeightedGraphImpl()

Creates a new instance of WeightedGraphImpl. Default algorithm for minimum spanning tree will use Kruskal's method (MinimumSpanningTreeKruskalAlgorithm).

Method Detail

addEdge

public WeightedEdge addEdge(Vertex v1,
                            Vertex v2,
                            double weight)
                     throws Exception

Convenience method to add a WeightedEdge with a specified weight into the WeightedGraph. The default addEdge( v1, v2 ) will add a WeightedEdge with zero weight, after which you can call setWeight() to specify the weight.

Specified by:

addEdge in interface WeightedGraph

Returns:

The WeightedEdge that has been added.

Throws:

Exception

getClosest

public Vertex getClosest(Vertex v)

Determines the Vertex that is 'closest' to the Vertex specified. The definition of the closest vertex in this context is a vertex that is directly adjacent to Vertex v where the edge has the least weight.

Specified by:

getClosest in interface WeightedGraph

Returns:

The Vertex closes to Vertex v.

minimumSpanningTree

public WeightedGraph minimumSpanningTree()

Determine a minimum spanning tree for the weighted graph. There is no guarantee that the same method call will result in the same result, as long as it satisifies the property of a minimum spanning tree.

Specified by:

minimumSpanningTree in interface WeightedGraph

Returns:

Subgraph connecting all the Vertices such that the sum of the weights of the Edges is at least as small as the sum of the weights of any other collection of Edges connecting all the Vertices.

shortestPath

public WeightedGraph shortestPath(Vertex vertex)

Determine a shortest path spanning tree for the weighted graph. Shortest path spanning tree need not be unique. Therefore, there is no guarantee that calling this method twice for the same weighted graph will return exactly the same shortest path spanning tree, unless there is only one shortest path spanning tree.

Also note that the graph returned by this method is a new instance of WeightedGraph. However, its vertices and edges will be the same instance as those of this WeightedGraph. Therefore, do not modify the contents of the returned WeightedGraph such that any of its vertices or edges are removed.

Specified by:

shortestPath in interface WeightedGraph

Parameters:

vertex - The Vertex in the weighted graph that we want to get the shortest paths to all other vertices.

Returns:

Shortest spanning subgtaph from the vertex parameter to all other vertices that are in the same connected set as the vertex.

setMinimumSpanningTreeAlgorithm

public void setMinimumSpanningTreeAlgorithm(MinimumSpanningTreeAlgorithm algo)

Sets the algorithm used to determine the minimum spanning tree.

setShortestPathAlgorithm

public void setShortestPathAlgorithm(ShortestPathAlgorithm algo)

Sets the algorithm used to determine the shortest path spanning tree.