salvo.jesus.graph.algorithm

Class TopologicalSorting

java.lang.Object

salvo.jesus.graph.algorithm.GraphTraversal

salvo.jesus.graph.algorithm.TopologicalSorting

All Implemented Interfaces:

Serializable

public class TopologicalSorting
extends GraphTraversal

A concrete subclass of GraphTraversal that performs a topological sort against a directed acyclic graph.

Author:

Jesus M. Salvo Jr.

See Also:

Serialized Form

Field Summary

Fields inherited from class salvo.jesus.graph.algorithm.GraphTraversal

OK, TERMINATEDBYVISITOR

Constructor Summary

Constructors

Constructor and Description
TopologicalSorting(DirectedAcyclicGraph dag) Creates an instance of TopologicalSorting that will perform a topological sort against a directed acyclic graph.

Method Summary

Modifier and Type	Method and Description
List	reverseTraverse() Perform a reverse topological sort of the entire directed acyclic graph.
List	reverseTraverse(Vertex startat) Perform a reverse topological sort of the subgraph reachable via outgoing edges from a specific vertex.
List	traverse() Perform a topological sort of the entire directed acyclic graph.
List	traverse(Vertex startat) Perform a topological sort of the subgraph reachable via outgoing edges from a specific vertex.
int	traverse(Vertex startat, List visited, Visitor visitor) Perform a topological sort of the subgraph reachable via outgoing edges from a specific vertex.
List	traverse(Vertex startat, Visitor visitor) Perform a topological sort of the subgraph reachable via outgoing edges from a specific vertex.

Methods inherited from class java.lang.Object

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

Constructor Detail

TopologicalSorting

public TopologicalSorting(DirectedAcyclicGraph dag)

Creates an instance of TopologicalSorting that will perform a topological sort against a directed acyclic graph.

Parameters:

dag - The DirectedAcyclicGraph on which topological sorting will be performed.

Method Detail

traverse

public int traverse(Vertex startat,
                    List visited,
                    Visitor visitor)

Perform a topological sort of the subgraph reachable via outgoing edges from a specific vertex. Other edges are ignored for the purpose of this sort.

Specified by:

traverse in class GraphTraversal

Parameters:

startat - The Vertex to which you want to start the traversal.

visited - List of vertices that has been visited, in the sequence they were visited; must be empty initially

visitor - Visitor object to visit each vertex as they are visited. Return value of the visitor is ignored.

traverse

public List traverse(Vertex startat,
                     Visitor visitor)

Perform a topological sort of the subgraph reachable via outgoing edges from a specific vertex. Other edges are ignored for the purpose of this sort.

Specified by:

traverse in class GraphTraversal

Parameters:

startat - The Vertex to which you want to start the traversal.

visitor - Visitor object to visit each vertex as they are visited. Return value of the visitor is ignored.

Returns:

A List of vertices in the order that they were visited.

traverse

public List traverse(Vertex startat)

Perform a topological sort of the subgraph reachable via outgoing edges from a specific vertex. Other edges are ignored for the purpose of this sort.

Specified by:

traverse in class GraphTraversal

Parameters:

startat - The Vertex to which you want to start the traversal.

Returns:

A List of vertices in the order that they were visited.

reverseTraverse

public List reverseTraverse(Vertex startat)

Perform a reverse topological sort of the subgraph reachable via outgoing edges from a specific vertex. Note that this does NOT traverse by incoming edges, as you might expect; rather, it first traverses by outgoing edges, and then simply reverses the order of the vertices encountered. This method is not part of the GraphTraversal abstract class, but is added here for convenience.

Parameters:

startat - The Vertex to which you want to start the traversal.

Returns:

A List of vertices in the order that they were visited.

traverse

public List traverse()

Perform a topological sort of the entire directed acyclic graph. Note that the sequence of vertices in the return List will not distinguish between connected components of the graph. This method is not part of the GraphTraversal abstract class, but is added here for convenience.

Returns:

List containing the sequence of the vertices visited in the entire directed acyclic graph, regardless of the connected components of the graph.

reverseTraverse

public List reverseTraverse()

Perform a reverse topological sort of the entire directed acyclic graph. Note that the sequence of vertices in the return List will not distinguish between connected components of the graph. This method is not part of the GraphTraversal abstract class, but is added here for convenience.

Returns:

List containing the sequence of the vertices visited in the entire directed acyclic graph, regardless of the connected components of the graph.