com.sparsity.sparksee.algorithms

Class WeakConnectivityDFS

java.lang.Object

com.sparsity.sparksee.algorithms.Connectivity

com.sparsity.sparksee.algorithms.WeakConnectivity

com.sparsity.sparksee.algorithms.WeakConnectivityDFS

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class WeakConnectivityDFS
extends WeakConnectivity

WeakConnectivityDFS class.

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.

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.

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

Check out the 'Algorithms' section in the SPARKSEE User Manual for more details on this.

Author:

Sparsity Technologies http://www.sparsity-technologies.com

Constructor Summary

Constructors

Constructor and Description
WeakConnectivityDFS(Session session) Creates a new instance of WeakConnectivityDFS.

Method Summary

Modifier and Type	Method and Description
void	addAllEdgeTypes() Allows connectivity through all edge types of the graph.
void	addAllNodeTypes() Allows connectivity through all node types of the graph.
void	addEdgeType(int type) Allows connectivity through edges of the given type.
void	addNodeType(int t) Allows connectivity through nodes of the given type.
void	excludeEdges(Objects edges) Set which edges can't be used.
void	excludeNodes(Objects nodes) Set which nodes can't be used.
ConnectedComponents	getConnectedComponents() Returns the results generated by the execution of the algorithm.
void	run() Executes the algorithm.
void	setMaterializedAttribute(java.lang.String attributeName) Creates a new common attribute type for all node types in the graph in order to store, persistently, the results related to the connected components found while executing this algorithm.

Methods inherited from class com.sparsity.sparksee.algorithms.Connectivity

close, isClosed

Methods inherited from class java.lang.Object

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

Constructor Detail

WeakConnectivityDFS

public WeakConnectivityDFS(Session session)

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:

session - [in] Session to get the graph from and calculate the connectivity

Method Detail

excludeNodes

public void excludeNodes(Objects nodes)

Set which nodes can't be used.

This will replace any previously specified set of excluded nodes. Should only be used to exclude the usage of specific nodes from allowed node types because it's less efficient than not allowing a node type.

Overrides:

excludeNodes in class WeakConnectivity

Parameters:

nodes - [in] A set of node identifiers that must be kept intact until the destruction of the class.

addAllEdgeTypes

public void addAllEdgeTypes()

Allows connectivity through all edge types of the graph.

In a weak connectivity the edges can be used in Any direction.

Overrides:

addAllEdgeTypes in class WeakConnectivity

getConnectedComponents

public ConnectedComponents getConnectedComponents()

Returns the results generated by the execution of the algorithm.

These results contain information related to the connected components found as the number of different components, the set of nodes contained in each component or many other data.

Overrides:

getConnectedComponents in class WeakConnectivity

Returns:

Returns an instance of the class ConnectedComponents which contain information related to the connected components found.

run

public void run()

Executes the algorithm.

Overrides:

run in class WeakConnectivity

addEdgeType

public void addEdgeType(int type)

Allows connectivity through edges of the given type.

In a weak connectivity the edges can be used in Any direction.

Overrides:

addEdgeType in class WeakConnectivity

Parameters:

type - [in] Edge type.

excludeEdges

public void excludeEdges(Objects edges)

Set which edges can't be used.

This will replace any previously specified set of excluded edges. Should only be used to exclude the usage of specific edges from allowed edge types because it's less efficient than not allowing an edge type.

Overrides:

excludeEdges in class WeakConnectivity

Parameters:

edges - [in] A set of edge identifiers that must be kept intact until the destruction of the class.

addNodeType

public void addNodeType(int t)

Allows connectivity through nodes of the given type.

Overrides:

addNodeType in class WeakConnectivity

Parameters:

t - null

setMaterializedAttribute

public void setMaterializedAttribute(java.lang.String attributeName)

Creates a new common attribute type for all node types in the graph in order to store, persistently, the results related to the connected components found while executing this algorithm.

Whenever the user wants to retrieve the results, even when the graph has been closed and opened again, it is only necessary to create a new instance of the class ConnectedComponents indicating the graph and the name of the common attribute type which stores the results. This instance will have all the information related to the connected components found in the moment of the execution of the algorithm that stored this data.

It is possible to run the algorithm without specifying this parameter in order to avoid materializing the results of the execution.

Overrides:

setMaterializedAttribute in class WeakConnectivity

Parameters:

attributeName - [in] The name of the common attribute type for all node types in the graph which will store persistently the results generated by the execution of the algorithm.

addAllNodeTypes

public void addAllNodeTypes()

Allows connectivity through all node types of the graph.

Overrides:

addAllNodeTypes in class WeakConnectivity