Package dev.roanh.gmark.lang.cpq

Class EdgeCPQ

java.lang.Object

dev.roanh.gmark.lang.generic.GenericEdge

dev.roanh.gmark.lang.cpq.EdgeCPQ

All Implemented Interfaces:

QueryFragment, CPQ, QueryLanguageSyntax, OutputFormal, OutputSQL, OutputXML

public class EdgeCPQ
extends GenericEdge
implements CPQ

CPQ modelling a single label traversal.

Field Summary

Fields inherited from class dev.roanh.gmark.lang.generic.GenericEdge

symbol

Fields inherited from interface dev.roanh.gmark.lang.cpq.CPQ

IDENTITY

Fields inherited from interface dev.roanh.gmark.lang.QueryLanguageSyntax

CHAR_DISJUNCTION, CHAR_INTERSECTION, CHAR_INVERSE, CHAR_JOIN, CHAR_KLEENE

Constructor Summary

Constructors

Constructor	Description
EdgeCPQ(Predicate symbol)	Constructs a new edge CPQ with the given label to traverse.

Method Summary

Modifier and Type	Method	Description
int	getDiameter()	Returns the diameter of this CPQ.
boolean	isLoop()	Tests if this CPQ is a loop, meaning its source and target are the same.
QueryGraphCPQ	toQueryGraph(QueryGraphCPQ.Vertex source, QueryGraphCPQ.Vertex target)	Computes and returns the query graph for this CPQ using the given source and target vertices for the computation.

Methods inherited from class dev.roanh.gmark.lang.generic.GenericEdge

getLabel, getOperationType, toAbstractSyntaxTree, toFormalSyntax, toString, writeSQL, writeXML

Methods inherited from class java.lang.Object

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

Methods inherited from interface dev.roanh.gmark.lang.cpq.CPQ

computeCore, getQueryLanguage, isHomomorphicTo, toQueryGraph

Methods inherited from interface dev.roanh.gmark.output.OutputFormal

toFormalSyntax

Methods inherited from interface dev.roanh.gmark.output.OutputSQL

toSQL, writeSQL

Methods inherited from interface dev.roanh.gmark.output.OutputXML

toXML, writeXML

Methods inherited from interface dev.roanh.gmark.ast.QueryFragment

getOperationType, toAbstractSyntaxTree

Constructor Details

EdgeCPQ

public EdgeCPQ(Predicate symbol)

Constructs a new edge CPQ with the given label to traverse.

Parameters:

symbol - The label to traverse.

Method Details

toQueryGraph

public QueryGraphCPQ toQueryGraph(QueryGraphCPQ.Vertex source,
 QueryGraphCPQ.Vertex target)

Description copied from interface: CPQ

Computes and returns the query graph for this CPQ using the given source and target vertices for the computation. Usually using CPQ.toQueryGraph() instead should be sufficient for most use cases, using this version instead can lead to unexpected results.

Specified by:

toQueryGraph in interface CPQ

Parameters:

source - The source vertex to use.

target - The target vertex to use.

Returns:

The query graph for this CPQ.

See Also:

• QueryGraphCPQ
• CPQ.toQueryGraph()

getDiameter

public int getDiameter()

Description copied from interface: CPQ

Returns the diameter of this CPQ. The diameter of a CPQ is the largest number of labels to which the join operation is applied. A simpler way to think of this concept is the length of the largest path through the CPQ from source to target.

Specified by:

getDiameter in interface CPQ

Returns:

The diameter of this CPQ.

isLoop

public boolean isLoop()

Description copied from interface: CPQ

Tests if this CPQ is a loop, meaning its source and target are the same. When visualised as a query graph this means that the source and target node are the same node. In its grammar form this means that there is an intersection with identity at the highest level in the CPQ.

Specified by:

isLoop in interface CPQ

Returns:

True if this CPQ is a loop.

See Also:

• QueryGraphCPQ