edu.upc.dama.dex.algorithms
Class WeakConnectivityDFS

java.lang.Object
  edu.upc.dama.dex.tasks.Task
      edu.upc.dama.dex.tasks.CompositeTask
          edu.upc.dama.dex.algorithms.Connectivity
              edu.upc.dama.dex.algorithms.WeakConnectivity
                  edu.upc.dama.dex.algorithms.WeakConnectivityDFS

All Implemented Interfaces:

Algorithm

public class WeakConnectivityDFS
extends WeakConnectivity

This class can be used to solve the problem of finding weakly connected components in an undirected graph or in a directed graph which will be considered as an undirected one.

Concretely, it consists in finding components where every pair (u,v) of nodes contained in it has a path from u to v and from v to u. This implementation is based on the Depth-First Search (DFS) algorithm.

It is possible to set some restrictions after constructing a new instance of this class and before running it in order to limit the results. Those restrictions are:

• The set of edge types which will be navigated through while traversing the graph. The method is Connectivity.addEdge(int edgetype) for adding one edge type and Connectivity.addAllEdges() for adding all edge types.
• The set of node types which will be navigated through while traversing the graph. The method is Connectivity.addNode(int nodetype) for adding one node type and Connectivity.addAllNodes() for adding all node types.

For each instance of this class, it is only allowed to run the algorithm once.

After the execution, we can retrieve the results stored in an instance of the class ConnectedComponents using the Connectivity.getConnectedComponents() method.

Please, see edu.upc.dama.dex.algorithms for further information related to how to use this class.

NOTE: It is required to indicate the set of edge types and node types before running this algorithm.

Author:

Sparsity Technologies

Field Summary

Fields inherited from interface edu.upc.dama.dex.algorithms.Algorithm

NAVIGATION_BACKWARD, NAVIGATION_FORWARD, NAVIGATION_UNDIRECTED

Constructor Summary

WeakConnectivityDFS(Graph graph)
Creates a new instance of WeakConnectivityDFS.

Method Summary

void	close() Closes the instance.
void	run() Runs the algorithm in order to find the connected components.

Methods inherited from class edu.upc.dama.dex.algorithms.Connectivity

addAllEdges, addAllNodes, addEdge, addNode, getConnectedComponents, setMaterializedAttribute

Methods inherited from class edu.upc.dama.dex.tasks.CompositeTask

cancel, execute, init

Methods inherited from class edu.upc.dama.dex.tasks.Task

main

Methods inherited from class java.lang.Object

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

Constructor Detail

WeakConnectivityDFS

public WeakConnectivityDFS(Graph graph)

Creates a new instance of WeakConnectivityDFS. After creating this instance is required to indicate the set of edge types and the set of node types which will be navigated through while traversing the graph in order to find the weak connected components.

Parameters:

graph - Graph on which the algorithm will be run.

Method Detail

close

public void close()

Description copied from class: Connectivity

Closes the instance.

Once executed, the instance becomes invalid.

Specified by:

close in class Connectivity

run

public void run()

Description copied from class: Connectivity

Runs the algorithm in order to find the connected components.

This method can be called only once.

Specified by:

run in class Connectivity