Class PathEvaluationContext

Evaluation Context for evaluating complex property paths in SPARQL.
Inheritance
System.Object
PathEvaluationContext
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.ToString()
Namespace: VDS.RDF.Query.Paths
Assembly: dotNetRDF.dll
Syntax
public class PathEvaluationContext

Constructors

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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.
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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

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CanAbortEarly

Gets whether pattern evaluation can be aborted early.
Declaration
public bool CanAbortEarly { get; }
Property Value
Type Description
System.Boolean
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).
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CompletePaths

Gets the hash set of complete paths generated so far.
Declaration
public HashSet<PotentialPath> CompletePaths { get; }
Property Value
Type Description
System.Collections.Generic.HashSet<PotentialPath>
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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
System.Boolean
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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
System.Boolean
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IsReversed

Gets/Sets whether the Path is currently reversed.
Declaration
public bool IsReversed { get; set; }
Property Value
Type Description
System.Boolean
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PathEnd

Gets the pattern which is the end of the path.
Declaration
public PatternItem PathEnd { get; }
Property Value
Type Description
PatternItem
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Paths

Gets the hash set of incomplete paths generated so far.
Declaration
public HashSet<PotentialPath> Paths { get; }
Property Value
Type Description
System.Collections.Generic.HashSet<PotentialPath>
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PathStart

Gets the pattern which is the start of the path.
Declaration
public PatternItem PathStart { get; }
Property Value
Type Description
PatternItem
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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
System.Boolean
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.

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SparqlContext

Gets the SPARQL Evaluation Context.
Declaration
public SparqlEvaluationContext SparqlContext { get; }
Property Value
Type Description
SparqlEvaluationContext

Methods

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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.
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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