salvo.jesus.graph.algorithm

Class CycleDetectionAlgorithm

java.lang.Object

salvo.jesus.graph.algorithm.CycleDetectionAlgorithm

Direct Known Subclasses:

CycleDetectionAlgorithmDFS

public abstract class CycleDetectionAlgorithm
extends Object

Abstract class for any algorithm implementing cycle detection on a Graph (directed or undirected). Methods act on either the entire graph or specific vertices or edges.

Author:

John V. Sichi

Field Summary

Fields

Modifier and Type	Field and Description
protected Graph	m_graph

Constructor Summary

Constructors

Constructor and Description
CycleDetectionAlgorithm(Graph graph) Example constructor for the algorithm.

Method Summary

Modifier and Type	Method and Description
abstract boolean	detectCycles() Perform cycle detection on the entire graph.
abstract boolean	detectCycles(Edge e) Determine whether an individual edge is on a cycle.
abstract boolean	detectCycles(Vertex v) Determine whether an individual vertex is on a cycle.
abstract void	findCycleSubgraph(Graph subgraph) Find the subgraph of all cycles.
abstract void	findCycleSubgraph(Graph subgraph, Edge e) Find the subgraph of all cycles which contain a particular edge.
abstract void	findCycleSubgraph(Graph subgraph, Vertex v) Find the subgraph of all cycles which contain a particular vertex.

Methods inherited from class java.lang.Object

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

Field Detail

m_graph

protected Graph m_graph

Constructor Detail

CycleDetectionAlgorithm

public CycleDetectionAlgorithm(Graph graph)

Example constructor for the algorithm.

Parameters:

graph - the Graph on which to operate

Method Detail

findCycleSubgraph

public abstract void findCycleSubgraph(Graph subgraph)
                                throws Exception

Find the subgraph of all cycles. The result is written into an existing graph rather than returned in a new graph; this leaves the caller control over the representation to use for the subgraph.

Parameters:

subgraph - an output parameter which receives the subgraph of all vertices and edges which participate in cycles; on entry, should be empty

Throws:

Exception - if subgraph.addEdge fails

findCycleSubgraph

public abstract void findCycleSubgraph(Graph subgraph,
                                       Vertex v)
                                throws Exception

Find the subgraph of all cycles which contain a particular vertex. The result is written into an existing graph rather than returned in a new graph; this leaves the caller control over the representation to use for the subgraph.

Parameters:

subgraph - an output parameter which receives the subgraph of all vertices and edges which participate in cycles containing v; on entry, should be empty

v - the vertex to test

Throws:

Exception - if subgraph.addEdge fails

findCycleSubgraph

public abstract void findCycleSubgraph(Graph subgraph,
                                       Edge e)
                                throws Exception

Find the subgraph of all cycles which contain a particular edge. The result is written into an existing graph rather than returned in a new graph; this leaves the caller control over the representation to use for the subgraph.

Parameters:

subgraph - an output parameter which receives the subgraph of all vertices and edges which participate in cycles containing e; on entry, should be empty

e - the edge to test

Throws:

Exception - if subgraph.addEdge fails

detectCycles

public abstract boolean detectCycles()

Perform cycle detection on the entire graph.

Returns:

true iff the graph contains at least one cycle

detectCycles

public abstract boolean detectCycles(Vertex v)

Determine whether an individual vertex is on a cycle.

Parameters:

v - the vertex to test

Returns:

true if v is on at least one cycle

detectCycles

public abstract boolean detectCycles(Edge e)

Determine whether an individual edge is on a cycle.

Parameters:

e - the edge to test

Returns:

true if e is on at least one cycle