Package dev.roanh.gmark.lang.cpq

Class ConcatCPQ

java.lang.Object

dev.roanh.gmark.lang.generic.GenericConcatenation<CPQ>

dev.roanh.gmark.lang.cpq.ConcatCPQ

All Implemented Interfaces:

QueryFragment, CPQ, QueryLanguageSyntax, OutputFormal, OutputSQL, OutputXML

public class ConcatCPQ
extends GenericConcatenation<CPQ>
implements CPQ

CPQ modelling the concatenation of a number of CPQs (also known as the join operation).

Field Summary

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

elements

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
ConcatCPQ(List<CPQ> cpqs)	Constructs a new concat CPQ with the given list of CPQs to concatenate.

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.
void	writeXML(IndentWriter writer)	Writes this object as XML to the given writer.

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

getOperationType, toAbstractSyntaxTree, toFormalSyntax, toString, writeSQL

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

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

getOperationType, toAbstractSyntaxTree

Constructor Details

ConcatCPQ

public ConcatCPQ(List<CPQ> cpqs)
          throws IllegalArgumentException

Constructs a new concat CPQ with the given list of CPQs to concatenate.

Parameters:

cpqs - The CPQs to concatenate.

Throws:

IllegalArgumentException - When the list of CPQs is empty.

Method Details

writeXML

public void writeXML(IndentWriter writer)

Description copied from interface: OutputXML

Writes this object as XML to the given writer.

Specified by:

writeXML in interface OutputXML

Parameters:

writer - The writer to write to.

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