edu.ucla.sspace.graph

Interface WeightedGraph<E extends WeightedEdge>

All Superinterfaces:

Graph<E>

All Known Implementing Classes:

SparseWeightedGraph, WeightedDirectedMultigraph

public interface WeightedGraph<E extends WeightedEdge>
extends Graph<E>

An interface specification for interacting with weighted Graph objects. This interface refines the Graph interface to associate each edge with a numeric value reflecting the strength of connection between the two vertices.

This interface permits having 0 or negative edge weights.

Author:

David Jurgens

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(E edge) Adds an edge between the two vertices, returning true if the edge was not previously present or if the edge was previously present but its weight was changed as a result (optional operation).
WeightedGraph<E>	copy(Set<Integer> vertices) Creates a copy of this graph containing only the specified number of vertices and all edges between those vertices.
Set<E>	edges() Returns the set of edges contained in this graph.
Set<E>	getAdjacencyList(int vertex) Returns the set of edges connected to the provided vertex.
Set<E>	getEdges(int vertex1, int vertex2) Returns the Edge instances connecting the two vertices or an empty set if the vertices are not connected.
double	strength(int vertex) Returns the sum of the weights for all edges connected to this vertex.
WeightedGraph<E>	subgraph(Set<Integer> vertices) Returns a view of this graph containing only the specified vertices where the returned graph's vertinces are renamed (0, ..., n).

Methods inherited from interface edu.ucla.sspace.graph.Graph

add, clear, clearEdges, contains, contains, contains, degree, getNeighbors, hasCycles, order, remove, remove, size, vertices

Method Detail

add

boolean add(E edge)

Adds an edge between the two vertices, returning true if the edge was not previously present or if the edge was previously present but its weight was changed as a result (optional operation). Adding an edge with the same vertice will not create a parallel edge, but will instead update the weight of that edge with the weight from most recently added.

Specified by:

add in interface Graph<E extends WeightedEdge>

Returns:

true if the edge was not previously present or if the edge was previously present but its weight was changed as a result

See Also:

#containsEdge(int, int)

copy

WeightedGraph<E> copy(Set<Integer> vertices)

Creates a copy of this graph containing only the specified number of vertices and all edges between those vertices. If vertices is empty a new, empty graph of this instance's type is returned. Any changes made to this graph will not be reflected in returned copy or vice-versa.

Specified by:

copy in interface Graph<E extends WeightedEdge>

edges

Set<E> edges()

Returns the set of edges contained in this graph.

Specified by:

edges in interface Graph<E extends WeightedEdge>

getAdjacencyList

Set<E> getAdjacencyList(int vertex)

Returns the set of edges connected to the provided vertex.

Specified by:

getAdjacencyList in interface Graph<E extends WeightedEdge>

getEdges

Set<E> getEdges(int vertex1,
              int vertex2)

Returns the Edge instances connecting the two vertices or an empty set if the vertices are not connected.

Specified by:

getEdges in interface Graph<E extends WeightedEdge>

strength

double strength(int vertex)

Returns the sum of the weights for all edges connected to this vertex. If this vertex is not in the graph, 0 is returned.

subgraph

WeightedGraph<E> subgraph(Set<Integer> vertices)

Returns a view of this graph containing only the specified vertices where the returned graph's vertinces are renamed (0, ..., n). This renaming is to ensure a conceptual distance between the "new" returned graph and the backing graph in terms of vertex labeling; for example, adding vertex n to the subgraph may not necessarily correspond to vertex n in the backing graph.

Only edges connecting two vertices in the provided set will be viewable in the subgraph. Any changes to the subgraph will be reflected in this graph and vice versa.

This view allows for direct manipulation of a part of the graph. For example, clearing this subgraph will remove all of its corresponding vertices and edges from the backing graph.

Specified by:

subgraph in interface Graph<E extends WeightedEdge>

Parameters:

vertices - the vertices to include in the subgraph