Class PathEvaluationContext

Evaluation Context for evaluating complex property paths in SPARQL.

Inheritance

object

PathEvaluationContext

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: VDS.RDF.Query.Paths

Assembly: dotNetRdf.dll

Syntax

public class PathEvaluationContext

Constructors

PathEvaluationContext(PathEvaluationContext)

Creates a new Path Evaluation Context copied from the given Context.

Declaration

public PathEvaluationContext(PathEvaluationContext context)

Parameters

Type	Name	Description
PathEvaluationContext	context	Path Evaluation Context.

PathEvaluationContext(SparqlEvaluationContext, PatternItem, PatternItem)

Creates a new Path Evaluation Context.

Declaration

public PathEvaluationContext(SparqlEvaluationContext context, PatternItem start, PatternItem end)

Parameters

Type	Name	Description
SparqlEvaluationContext	context	SPARQL Evaluation Context.
PatternItem	start	End point of the Path.
PatternItem	end	Start point of the Path.

Properties

CanAbortEarly

Gets whether pattern evaluation can be aborted early.

Declaration

public bool CanAbortEarly { get; }

Property Value

Type	Description
bool

Remarks

Useful when both the start and end of the path are fixed (non-variables) which means that we can stop evaluating once we find the path (if it exists).

CompletePaths

Gets the hash set of complete paths generated so far.

Declaration

public HashSet<PotentialPath> CompletePaths { get; }

Property Value

Type	Description
HashSet<PotentialPath>

IsFirst

Gets/Sets whether this is the first part of the Path to be evaluated.

Declaration

public bool IsFirst { get; set; }

Property Value

Type	Description
bool

IsLast

Gets/Sets whether this is the last part of the Path to be evaluated.

Declaration

public bool IsLast { get; set; }

Property Value

Type	Description
bool

IsReversed

Gets/Sets whether the Path is currently reversed.

Declaration

public bool IsReversed { get; set; }

Property Value

Type	Description
bool

PathEnd

Gets the pattern which is the end of the path.

Declaration

public PatternItem PathEnd { get; }

Property Value

Type	Description
PatternItem

PathStart

Gets the pattern which is the start of the path.

Declaration

public PatternItem PathStart { get; }

Property Value

Type	Description
PatternItem

Paths

Gets the hash set of incomplete paths generated so far.

Declaration

public HashSet<PotentialPath> Paths { get; }

Property Value

Type	Description
HashSet<PotentialPath>

PermitsNewPaths

Gets/Sets whether new paths can be introduced when not evaluating the first part of the path.

Declaration

public bool PermitsNewPaths { get; set; }

Property Value

Type	Description
bool

Remarks

This is required when we have a path like ?x foaf:knows* /foaf:knows ?y and ?x is not bound prior to the path being executed. Since we permit zero-length paths we should return the names of everyone even if they don't know anyone.

The cases where ?x is already bound are handled elsewhere as we can just introduce zero-length paths for every existing binding for ?x.

SparqlContext

Gets the SPARQL Evaluation Context.

Declaration

public SparqlEvaluationContext SparqlContext { get; }

Property Value

Type	Description
SparqlEvaluationContext

Methods

AddCompletePath(PotentialPath)

Adds a new path to the list of complete paths.

Declaration

public void AddCompletePath(PotentialPath p)

Parameters

Type	Name	Description
PotentialPath	p	Path.

AddPath(PotentialPath)

Adds a new path to the list of current incomplete paths.

Declaration

public void AddPath(PotentialPath p)

Parameters

Type	Name	Description
PotentialPath	p	Path.

Extension Methods

Extensions.ToSafeString(object)

Extensions.AsEnumerable<T>(T)