java.lang.Object
- org.jgrapht.graph.GraphWalk<V,E>

Type Parameters:

V - the graph vertex type

E - the graph edge type

All Implemented Interfaces:

Serializable, GraphPath<V,E>
```
public class GraphWalk<V,E>
extends Object
implements GraphPath<V,E>, Serializable
```
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 $v_0, e_0, v_1, e_1, v_2, \dotso, v_{k-1}, e_{k-1}, v_{k}$, such that for $1 \leq i \leq k$, 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.
Two special cases exist:
1. A singleton GraphWalk has an empty edge list (the length of the path equals 0), the vertex list contains a single vertex v, and the start and end vertex equal v.
2. An empty Graphwalk has empty edge and vertex lists, and the start and end vertex are both null.
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.
Note: Serialization of a GraphWalk implies the serialization of the entire underlying graph.
Author:

Joris Kinable

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`protected List<E>`	`edgeList`
`protected V`	`endVertex`
`protected Graph<V,E>`	`graph`
`protected V`	`startVertex`
`protected List<V>`	`vertexList`
`protected double`	`weight`

Constructor Summary

Constructors
Constructor	Description
`GraphWalk(Graph<V,E> graph, List<V> vertexList, double weight)`	Creates a walk defined by a sequence of vertices.
`GraphWalk(Graph<V,E> graph, V startVertex, V endVertex, List<E> edgeList, double weight)`	Creates a walk defined by a sequence of edges.
`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.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`GraphWalk<V,E>`	`concat(GraphWalk<V,E> extension, Function<GraphWalk<V,E>,Double> walkWeightCalculator)`	Concatenates the specified GraphWalk to the end of this GraphWalk.
`static <V,E> GraphWalk<V,E>`	`emptyWalk(Graph<V,E> graph)`	Convenience method which creates an empty walk.
`boolean`	`equals(Object o)`
`List<E>`	`getEdgeList()`	Returns the edges making up the path.
`V`	`getEndVertex()`	Returns the end vertex in the path.
`Graph<V,E>`	`getGraph()`	Returns the graph over which this path is defined.
`int`	`getLength()`	Returns the length of the path, measured in the number of edges.
`V`	`getStartVertex()`	Returns the start vertex in the path.
`List<V>`	`getVertexList()`	Returns the path as a sequence of vertices.
`double`	`getWeight()`	Returns the weight assigned to the path.
`int`	`hashCode()`
`boolean`	`isEmpty()`	Returns true if the path is an empty path, that is, a path with startVertex=endVertex=null and with an empty vertex and edge list.
`GraphWalk<V,E>`	`reverse()`	Reverses the direction of the walk.
`GraphWalk<V,E>`	`reverse(Function<GraphWalk<V,E>,Double> walkWeightCalculator)`	Reverses the direction of the walk.
`void`	`setWeight(double weight)`	Updates the weight of this walk
`static <V,E> GraphWalk<V,E>`	`singletonWalk(Graph<V,E> graph, V v)`	Convenience method which creates a walk consisting of a single vertex with weight 0.0.
`static <V,E> GraphWalk<V,E>`	`singletonWalk(Graph<V,E> graph, V v, double weight)`	Convenience method which creates a walk consisting of a single vertex.
`String`	`toString()`
`void`	`verify()`	Convenience method which verifies whether the given path is feasible wrt the input graph and forms an actual path.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- 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 ($v_0$ and $v_k$) 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
  - setWeight
```
public void setWeight(double weight)
```
    Updates the weight of this walk
    
    Parameters:
    
    weight - weight of the walk
  - 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
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - reverse
```
public GraphWalk<V,E> reverse()
```
    Reverses the direction of the walk. In case of directed/mixed graphs, the arc directions will be reversed. An exception is thrown if reversing an arc $(u,v)$ is impossible because arc $(v,u)$ is not present in the graph. The weight of the resulting walk equals the sum of edge weights in the walk.
    
    Returns:
    
    a reversed GraphWalk
    
    Throws:
    
    InvalidGraphWalkException - if the path is invalid
  - reverse
```
public GraphWalk<V,E> reverse(Function<GraphWalk<V,E>,Double> walkWeightCalculator)
```
    Reverses the direction of the walk. In case of directed/mixed graphs, the arc directions will be reversed. An exception is thrown if reversing an arc $(u,v)$ is impossible because arc $(v,u)$ is not present in the graph.
    
    Parameters:
    
    walkWeightCalculator - Function used to calculate the weight of the reversed GraphWalk
    
    Returns:
    
    a reversed GraphWalk
    
    Throws:
    
    InvalidGraphWalkException - if the path is invalid
  - concat
```
public GraphWalk<V,E> concat(GraphWalk<V,E> extension,
                                   Function<GraphWalk<V,E>,Double> walkWeightCalculator)
```
    Concatenates the specified GraphWalk to the end of this GraphWalk. This action can only be performed if the end vertex of this GraphWalk is the same as the start vertex of the extending GraphWalk
    
    Parameters:
    
    extension - GraphPath used for the concatenation.
    
    walkWeightCalculator - Function used to calculate the weight of the GraphWalk obtained after the concatenation.
    
    Returns:
    
    a GraphWalk that represents the concatenation of this object's walk followed by the walk specified in the extension argument.
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if the path is an empty path, that is, a path with startVertex=endVertex=null and with an empty vertex and edge list.
    
    Returns:
    
    Returns true if the path is an empty path.
  - verify
```
public void verify()
```
    Convenience method which verifies whether the given path is feasible wrt the input graph and forms an actual path.
    
    Throws:
    
    InvalidGraphWalkException - if the path is invalid
  - emptyWalk
```
public static <V,E> GraphWalk<V,E> emptyWalk(Graph<V,E> graph)
```
    Convenience method which creates an empty walk.
    
    Type Parameters:
    
    V - vertex type
    
    E - edge type
    
    Parameters:
    
    graph - input graph
    
    Returns:
    
    an empty walk
  - singletonWalk
```
public static <V,E> GraphWalk<V,E> singletonWalk(Graph<V,E> graph,
                                                             V v)
```
    Convenience method which creates a walk consisting of a single vertex with weight 0.0.
    
    Type Parameters:
    
    V - vertex type
    
    E - edge type
    
    Parameters:
    
    graph - input graph
    
    v - single vertex
    
    Returns:
    
    an empty walk
  - singletonWalk
```
public static <V,E> GraphWalk<V,E> singletonWalk(Graph<V,E> graph,
                                                             V v,
                                                             double weight)
```
    Convenience method which creates a walk consisting of a single vertex.
    
    Type Parameters:
    
    V - vertex type
    
    E - edge type
    
    Parameters:
    
    graph - input graph
    
    v - single vertex
    
    weight - weight of the path
    
    Returns:
    
    an empty walk

Class GraphWalk<V,​E>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

graph

vertexList

edgeList

startVertex

endVertex

weight

Constructor Detail

GraphWalk

GraphWalk

GraphWalk

Method Detail

getGraph

getStartVertex

getEndVertex

getEdgeList

getVertexList

getWeight

setWeight

getLength

toString

equals

hashCode

reverse

reverse

concat

isEmpty

verify

emptyWalk

singletonWalk

singletonWalk

Class GraphWalk<V,E>