org.jgrapht.graph

Class GraphWalk<V,E>

• Type Parameters:
V - the graph vertex type
E - the graph edge type
All Implemented Interfaces:
GraphPath<V,E>

public class GraphWalk<V,E>
extends Object
implements GraphPath<V,E>
A walk in a graph is an alternating sequence of vertices and edges, starting and ending at a vertex, in which each edge is adjacent in the sequence to its two endpoints. More precisely, a walk is a connected sequence of vertices and edges in a graph v0, e0, v1, e1, v2,....vk-1, ek-1, vk, such that for 1<=i<=k<, the edge e_i has endpoints v_(i-1) and v_i. The class makes no assumptions with respect to the shape of the walk: edges may be repeated, and the start and end point of the walk may be different. See http://mathworld.wolfram.com/Walk.html GraphWalk is the default implementation of GraphPath. This class is implemented as a light-weight data structure; this class does not verify whether the sequence of edges or the sequence of vertices provided during construction forms an actual walk. It is the responsibility of the invoking class to provide correct input data.
Author:
John Sichi
• Field Detail

• graph

protected Graph<V,E> graph
• vertexList

protected List<V> vertexList
• edgeList

protected List<E> edgeList
• startVertex

protected V startVertex
• endVertex

protected V endVertex
• weight

protected double weight
• Constructor Detail

• GraphWalk

public GraphWalk(Graph<V,E> graph,
V startVertex,
V endVertex,
List<E> edgeList,
double weight)
Creates a walk defined by a sequence of edges. A walk defined by its edges can be specified for non-simple graphs. Edge repetition is permitted, the start and end point points (v0 and vk) can be different.
Parameters:
graph - the graph
startVertex - the starting vertex
endVertex - the last vertex of the path
edgeList - the list of edges of the path
weight - the total weight of the path
• GraphWalk

public GraphWalk(Graph<V,E> graph,
List<V> vertexList,
double weight)
Creates a walk defined by a sequence of vertices. Note that the input graph must be simple, otherwise the vertex sequence does not necessarily define a unique path. Furthermore, all vertices must be pairwise adjacent.
Parameters:
graph - the graph
vertexList - the list of vertices of the path
weight - the total weight of the path
• GraphWalk

public GraphWalk(Graph<V,E> graph,
V startVertex,
V endVertex,
List<V> vertexList,
List<E> edgeList,
double weight)
Creates a walk defined by both a sequence of edges and a sequence of vertices. Note that both the sequence of edges and the sequence of vertices must describe the same path! This is not verified during the construction of the walk. This constructor makes it possible to store both a vertex and an edge view of the same walk, thereby saving computational overhead when switching from one to the other.
Parameters:
graph - the graph
startVertex - the starting vertex
endVertex - the last vertex of the path
vertexList - the list of vertices of the path
edgeList - the list of edges of the path
weight - the total weight of the path
• Method Detail

• getGraph

public Graph<V,E> getGraph()
Description copied from interface: GraphPath
Returns the graph over which this path is defined. The path may also be valid with respect to other graphs.
Specified by:
getGraph in interface GraphPath<V,E>
Returns:
the containing graph
• getStartVertex

public V getStartVertex()
Description copied from interface: GraphPath
Returns the start vertex in the path.
Specified by:
getStartVertex in interface GraphPath<V,E>
Returns:
the start vertex
• getEndVertex

public V getEndVertex()
Description copied from interface: GraphPath
Returns the end vertex in the path.
Specified by:
getEndVertex in interface GraphPath<V,E>
Returns:
the end vertex
• getEdgeList

public List<E> getEdgeList()
Description copied from interface: GraphPath
Returns the edges making up the path. The first edge in this path is incident to the start vertex. The last edge is incident to the end vertex. The vertices along the path can be obtained by traversing from the start vertex, finding its opposite across the first edge, and then doing the same successively across subsequent edges; see GraphPath.getVertexList().

Whether or not the returned edge list is modifiable depends on the path implementation.

Specified by:
getEdgeList in interface GraphPath<V,E>
Returns:
list of edges traversed by the path
• getVertexList

public List<V> getVertexList()
Description copied from interface: GraphPath
Returns the path as a sequence of vertices.
Specified by:
getVertexList in interface GraphPath<V,E>
Returns:
path, denoted by a list of vertices
• getWeight

public double getWeight()
Description copied from interface: GraphPath
Returns the weight assigned to the path. Typically, this will be the sum of the weights of the edge list entries (as defined by the containing graph), but some path implementations may use other definitions.
Specified by:
getWeight in interface GraphPath<V,E>
Returns:
the weight of the path
• getLength

public int getLength()
Description copied from interface: GraphPath
Returns the length of the path, measured in the number of edges.
Specified by:
getLength in interface GraphPath<V,E>
Returns:
the length of the path, measured in the number of edges