Class LeviathanQueryProcessor

Default SPARQL Query Processor provided by the library's Leviathan SPARQL Engine.

Inheritance

object

LeviathanQueryProcessor

ExplainQueryProcessor

Implements

ISparqlQueryProcessor

ISparqlQueryAlgebraProcessor<BaseMultiset, SparqlEvaluationContext>

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

Assembly: dotNetRdf.dll

Syntax

public class LeviathanQueryProcessor : ISparqlQueryProcessor, ISparqlQueryAlgebraProcessor<BaseMultiset, SparqlEvaluationContext>

Remarks

The Leviathan Query Processor simply invokes the Evaluate method of the SPARQL Algebra it is asked to process.

In future releases much of the Leviathan Query engine logic will be moved into this class to make it possible for implementors to override specific bits of the algebra processing but this is not possible at this time.

Constructors

LeviathanQueryProcessor(IInMemoryQueryableStore, Action<LeviathanQueryOptions>)

Creates a new Leviathan Query Processor.

Declaration

public LeviathanQueryProcessor(IInMemoryQueryableStore store, Action<LeviathanQueryOptions> options = null)

Parameters

Type	Name	Description
IInMemoryQueryableStore	store	Triple Store.
Action<LeviathanQueryOptions>	options	Set the processor options.

LeviathanQueryProcessor(ISparqlDataset, Action<LeviathanQueryOptions>)

Creates a new Leviathan Query Processor.

Declaration

public LeviathanQueryProcessor(ISparqlDataset data, Action<LeviathanQueryOptions> options = null)

Parameters

Type	Name	Description
ISparqlDataset	data	SPARQL Dataset.
Action<LeviathanQueryOptions>	options	Set the processor options.

LeviathanQueryProcessor(ISparqlDataset, LeviathanQueryOptions)

Create a new Leviathan query processor.

Declaration

public LeviathanQueryProcessor(ISparqlDataset data, LeviathanQueryOptions options)

Parameters

Type	Name	Description
ISparqlDataset	data	SPARQL dataset.
LeviathanQueryOptions	options	Query processor options.

Exceptions

Type	Condition
ArgumentNullException

Methods

EvaluateStep(IPathOperator, SparqlEvaluationContext, List<INode>, bool)

Evaluates a step of the Path.

Declaration

protected List<INode> EvaluateStep(IPathOperator pathOperator, SparqlEvaluationContext context, List<INode> path, bool reverse)

Parameters

Type	Name	Description
IPathOperator	pathOperator	Path operator.
SparqlEvaluationContext	context	Context.
List<INode>	path	Paths.
bool	reverse	Whether to evaluate Paths in reverse.

Returns

Type	Description
List<INode>

GetContext()

Creates a new Evaluation Context.

Declaration

protected SparqlEvaluationContext GetContext()

Returns

Type	Description
SparqlEvaluationContext

GetPathStarts(IPathOperator, SparqlEvaluationContext, List<List<INode>>, bool)

Determines the starting points for Path evaluation.

Declaration

protected void GetPathStarts(IPathOperator pathOperator, SparqlEvaluationContext context, List<List<INode>> paths, bool reverse)

Parameters

Type	Name	Description
IPathOperator	pathOperator	Path Operator.
SparqlEvaluationContext	context	Evaluation Context.
List<List<INode>>	paths	Paths.
bool	reverse	Whether to evaluate Paths in reverse.

ProcessAlgebra(ISparqlAlgebra, SparqlEvaluationContext)

Processes SPARQL Algebra.

Declaration

public BaseMultiset ProcessAlgebra(ISparqlAlgebra algebra, SparqlEvaluationContext context)

Parameters

Type	Name	Description
ISparqlAlgebra	algebra	Algebra.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessAsk(Ask, SparqlEvaluationContext)

Processes an Ask.

Declaration

public virtual BaseMultiset ProcessAsk(Ask ask, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Ask	ask	Ask.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessAskAnyTriples(AskAnyTriples, SparqlEvaluationContext)

Processes an optimised ASK of the form ASK WHERE { ?s ?p ?o }.

Declaration

public virtual BaseMultiset ProcessAskAnyTriples(AskAnyTriples askAny, SparqlEvaluationContext context)

Parameters

Type	Name	Description
AskAnyTriples	askAny
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessBgp(IBgp, SparqlEvaluationContext)

Processes a BGP.

Declaration

public virtual BaseMultiset ProcessBgp(IBgp bgp, SparqlEvaluationContext context)

Parameters

Type	Name	Description
IBgp	bgp	BGP.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessBindPattern(BindPattern, SparqlEvaluationContext)

Process a BindPattern.

Declaration

public BaseMultiset ProcessBindPattern(BindPattern bindPattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
BindPattern	bindPattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessBindings(Bindings, SparqlEvaluationContext)

Processes a Bindings modifier.

Declaration

public virtual BaseMultiset ProcessBindings(Bindings b, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Bindings	b	Bindings.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessBoundFilter(BoundFilter, SparqlEvaluationContext)

Process a BoundFilter.

Declaration

public BaseMultiset ProcessBoundFilter(BoundFilter filter, SparqlEvaluationContext context)

Parameters

Type	Name	Description
BoundFilter	filter
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessChainFilter(ChainFilter, SparqlEvaluationContext)

Process a ChainFilter.

Declaration

public BaseMultiset ProcessChainFilter(ChainFilter filter, SparqlEvaluationContext context)

Parameters

Type	Name	Description
ChainFilter	filter
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessDistinct(Distinct, SparqlEvaluationContext)

Processes a Distinct modifier.

Declaration

public virtual BaseMultiset ProcessDistinct(Distinct distinct, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Distinct	distinct	Distinct modifier.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessExistsJoin(IExistsJoin, SparqlEvaluationContext)

Processes an Exists Join.

Declaration

public virtual BaseMultiset ProcessExistsJoin(IExistsJoin existsJoin, SparqlEvaluationContext context)

Parameters

Type	Name	Description
IExistsJoin	existsJoin	Exists Join.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessExtend(Extend, SparqlEvaluationContext)

Processes an Extend.

Declaration

public virtual BaseMultiset ProcessExtend(Extend extend, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Extend	extend	Extend.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessFilter(IFilter, SparqlEvaluationContext)

Processes a Filter.

Declaration

public virtual BaseMultiset ProcessFilter(IFilter filter, SparqlEvaluationContext context)

Parameters

Type	Name	Description
IFilter	filter	Filter.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessFilterPattern(FilterPattern, SparqlEvaluationContext)

Process a FilterPattern.

Declaration

public BaseMultiset ProcessFilterPattern(FilterPattern filterPattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
FilterPattern	filterPattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessGraph(Graph, SparqlEvaluationContext)

Processes a Graph.

Declaration

public virtual BaseMultiset ProcessGraph(Graph graph, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Graph	graph	Graph.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessGroupBy(GroupBy, SparqlEvaluationContext)

Processes a Group By.

Declaration

public virtual BaseMultiset ProcessGroupBy(GroupBy groupBy, SparqlEvaluationContext context)

Parameters

Type	Name	Description
GroupBy	groupBy	Group By.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessHaving(Having, SparqlEvaluationContext)

Processes a Having.

Declaration

public virtual BaseMultiset ProcessHaving(Having having, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Having	having	Having.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessJoin(IJoin, SparqlEvaluationContext)

Processes a Join.

Declaration

public virtual BaseMultiset ProcessJoin(IJoin join, SparqlEvaluationContext context)

Parameters

Type	Name	Description
IJoin	join	Join.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessLeftJoin(ILeftJoin, SparqlEvaluationContext)

Processes a LeftJoin.

Declaration

public virtual BaseMultiset ProcessLeftJoin(ILeftJoin leftJoin, SparqlEvaluationContext context)

Parameters

Type	Name	Description
ILeftJoin	leftJoin	Left Join.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessLetPattern(LetPattern, SparqlEvaluationContext)

Process a LetPattern.

Declaration

public BaseMultiset ProcessLetPattern(LetPattern letPattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
LetPattern	letPattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessMinus(IMinus, SparqlEvaluationContext)

Processes a Minus.

Declaration

public virtual BaseMultiset ProcessMinus(IMinus minus, SparqlEvaluationContext context)

Parameters

Type	Name	Description
IMinus	minus	Minus.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessNegatedPropertySet(NegatedPropertySet, SparqlEvaluationContext)

Processes a Negated Property Set.

Declaration

public virtual BaseMultiset ProcessNegatedPropertySet(NegatedPropertySet negPropSet, SparqlEvaluationContext context)

Parameters

Type	Name	Description
NegatedPropertySet	negPropSet	Negated Property Set.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessNullOperator(NullOperator, SparqlEvaluationContext)

Processes a Null Operator.

Declaration

public virtual BaseMultiset ProcessNullOperator(NullOperator nullOp, SparqlEvaluationContext context)

Parameters

Type	Name	Description
NullOperator	nullOp	Null Operator.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessOneOrMorePath(OneOrMorePath, SparqlEvaluationContext)

Processes a One or More Path.

Declaration

public virtual BaseMultiset ProcessOneOrMorePath(OneOrMorePath oneOrMorePath, SparqlEvaluationContext context)

Parameters

Type	Name	Description
OneOrMorePath	oneOrMorePath	Path.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessOrderBy(OrderBy, SparqlEvaluationContext)

Processes an Order By.

Declaration

public virtual BaseMultiset ProcessOrderBy(OrderBy orderBy, SparqlEvaluationContext context)

Parameters

Type	Name	Description
OrderBy	orderBy
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessPropertyFunction(PropertyFunction, SparqlEvaluationContext)

Process a PropertyFunction.

Declaration

public BaseMultiset ProcessPropertyFunction(PropertyFunction propertyFunction, SparqlEvaluationContext context)

Parameters

Type	Name	Description
PropertyFunction	propertyFunction
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessPropertyFunctionPattern(PropertyFunctionPattern, SparqlEvaluationContext)

Process a PropertyFunctionPattern.

Declaration

public BaseMultiset ProcessPropertyFunctionPattern(PropertyFunctionPattern propFunctionPattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
PropertyFunctionPattern	propFunctionPattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessPropertyPath(PropertyPath, SparqlEvaluationContext)

Processes a Property Path.

Declaration

public virtual BaseMultiset ProcessPropertyPath(PropertyPath path, SparqlEvaluationContext context)

Parameters

Type	Name	Description
PropertyPath	path	Path.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessPropertyPathPattern(PropertyPathPattern, SparqlEvaluationContext)

Process a PropertyPathPattern.

Declaration

public BaseMultiset ProcessPropertyPathPattern(PropertyPathPattern propertyPathPattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
PropertyPathPattern	propertyPathPattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessQuery(IRdfHandler, ISparqlResultsHandler, SparqlQuery)

Processes a SPARQL Query sending the results to a RDF/SPARQL Results handler as appropriate.

Declaration

public void ProcessQuery(IRdfHandler rdfHandler, ISparqlResultsHandler resultsHandler, SparqlQuery query)

Parameters

Type	Name	Description
IRdfHandler	rdfHandler	RDF Handler.
ISparqlResultsHandler	resultsHandler	Results Handler.
SparqlQuery	query	SPARQL Query.

ProcessQuery(IRdfHandler, ISparqlResultsHandler, SparqlQuery, QueryCallback, object)

Processes a SPARQL Query asynchronously passing the results to the relevant handler and invoking the callback when the query completes.

Declaration

public void ProcessQuery(IRdfHandler rdfHandler, ISparqlResultsHandler resultsHandler, SparqlQuery query, QueryCallback callback, object state)

Parameters

Type	Name	Description
IRdfHandler	rdfHandler	RDF Handler.
ISparqlResultsHandler	resultsHandler	Results Handler.
SparqlQuery	query	SPARQL Query.
QueryCallback	callback	Callback.
object	state	State to pass to the callback.

Remarks

In the event of a success the callback will be invoked, if there is an error the callback will be invoked and passed an instance of AsyncError which contains details of the error and the original state information passed in.

ProcessQuery(SparqlQuery)

Processes a SPARQL Query.

Declaration

public object ProcessQuery(SparqlQuery query)

Parameters

Type	Name	Description
SparqlQuery	query	SPARQL Query.

Returns

Type	Description
object

ProcessQuery(SparqlQuery, GraphCallback, SparqlResultsCallback, object)

Processes a SPARQL Query asynchronously invoking the relevant callback when the query completes.

Declaration

public void ProcessQuery(SparqlQuery query, GraphCallback rdfCallback, SparqlResultsCallback resultsCallback, object state)

Parameters

Type	Name	Description
SparqlQuery	query	SPARQL QUery.
GraphCallback	rdfCallback	Callback for queries that return a Graph.
SparqlResultsCallback	resultsCallback	Callback for queries that return a Result Set.
object	state	State to pass to the callback.

Remarks

In the event of a success the appropriate callback will be invoked, if there is an error both callbacks will be invoked and passed an instance of AsyncError which contains details of the error and the original state information passed in.

ProcessQueryAsync(IRdfHandler, ISparqlResultsHandler, SparqlQuery)

Process a SPARQL query asynchronously, passing the results to teh relevant handler.

Declaration

public Task ProcessQueryAsync(IRdfHandler rdfHandler, ISparqlResultsHandler resultsHandler, SparqlQuery query)

Parameters

Type	Name	Description
IRdfHandler	rdfHandler	RDF handler invoked for queries that return RDF graphs.
ISparqlResultsHandler	resultsHandler	Results handler invoked for queries that return SPARQL results sets.
SparqlQuery	query	SPARQL query.

Returns

Type	Description
Task

ProcessQueryAsync(SparqlQuery)

Process a SPARQL query asynchronously returning either a SparqlResultSet or a IGraph depending on the type of the query.

Declaration

public Task<object> ProcessQueryAsync(SparqlQuery query)

Parameters

Type	Name	Description
SparqlQuery	query	SPARQL query.

Returns

Type	Description
Task<object>	Either an <see cref="IGraph">IGraph</see> instance of a <see cref="SparqlResultSet">SparqlResultSet</see> depending on the type of the query.

ProcessReduced(Reduced, SparqlEvaluationContext)

Processes a Reduced modifier.

Declaration

public virtual BaseMultiset ProcessReduced(Reduced reduced, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Reduced	reduced	Reduced modifier.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessSelect(Select, SparqlEvaluationContext)

Processes a Select.

Declaration

public virtual BaseMultiset ProcessSelect(Select select, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Select	select	Select.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessSelectDistinctGraphs(SelectDistinctGraphs, SparqlEvaluationContext)

Processes a Select Distinct Graphs.

Declaration

public virtual BaseMultiset ProcessSelectDistinctGraphs(SelectDistinctGraphs selDistGraphs, SparqlEvaluationContext context)

Parameters

Type	Name	Description
SelectDistinctGraphs	selDistGraphs	Select Distinct Graphs.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessService(Service, SparqlEvaluationContext)

Processes a Service.

Declaration

public virtual BaseMultiset ProcessService(Service service, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Service	service	Service.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessSingleValueRestrictionFilter(SingleValueRestrictionFilter, SparqlEvaluationContext)

Process a SingleValueRestrictionFilter.

Declaration

public BaseMultiset ProcessSingleValueRestrictionFilter(SingleValueRestrictionFilter filter, SparqlEvaluationContext context)

Parameters

Type	Name	Description
SingleValueRestrictionFilter	filter
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessSlice(Slice, SparqlEvaluationContext)

Processes a Slice modifier.

Declaration

public virtual BaseMultiset ProcessSlice(Slice slice, SparqlEvaluationContext context)

Parameters

Type	Name	Description
Slice	slice	Slice modifier.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessSubQuery(SubQuery, SparqlEvaluationContext)

Processes a Subquery.

Declaration

public virtual BaseMultiset ProcessSubQuery(SubQuery subquery, SparqlEvaluationContext context)

Parameters

Type	Name	Description
SubQuery	subquery	Subquery.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessSubQueryPattern(SubQueryPattern, SparqlEvaluationContext)

Process a SubQueryPattern.

Declaration

public BaseMultiset ProcessSubQueryPattern(SubQueryPattern subQueryPattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
SubQueryPattern	subQueryPattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessTriplePattern(TriplePattern, SparqlEvaluationContext)

Process a TriplePattern.

Declaration

public BaseMultiset ProcessTriplePattern(TriplePattern triplePattern, SparqlEvaluationContext context)

Parameters

Type	Name	Description
TriplePattern	triplePattern
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessUnaryExpressionFilter(UnaryExpressionFilter, SparqlEvaluationContext)

Process a UnaryExpressionFilter.

Declaration

public BaseMultiset ProcessUnaryExpressionFilter(UnaryExpressionFilter filter, SparqlEvaluationContext context)

Parameters

Type	Name	Description
UnaryExpressionFilter	filter
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessUnion(IUnion, SparqlEvaluationContext)

Processes a Union.

Declaration

public virtual BaseMultiset ProcessUnion(IUnion union, SparqlEvaluationContext context)

Parameters

Type	Name	Description
IUnion	union	Union.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessUnknownOperator(ISparqlAlgebra, SparqlEvaluationContext)

Invoked to process any other algebra class not covered above. In particular engine-specific optimised algebra classes.

Declaration

public virtual BaseMultiset ProcessUnknownOperator(ISparqlAlgebra op, SparqlEvaluationContext context)

Parameters

Type	Name	Description
ISparqlAlgebra	op
SparqlEvaluationContext	context

Returns

Type	Description
BaseMultiset

ProcessZeroLengthPath(ZeroLengthPath, SparqlEvaluationContext)

Processes a Zero Length Path.

Declaration

public virtual BaseMultiset ProcessZeroLengthPath(ZeroLengthPath path, SparqlEvaluationContext context)

Parameters

Type	Name	Description
ZeroLengthPath	path	Path.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

ProcessZeroOrMorePath(ZeroOrMorePath, SparqlEvaluationContext)

Processes a Zero or More Path.

Declaration

public virtual BaseMultiset ProcessZeroOrMorePath(ZeroOrMorePath zeroOrMorePath, SparqlEvaluationContext context)

Parameters

Type	Name	Description
ZeroOrMorePath	zeroOrMorePath	Path.
SparqlEvaluationContext	context	SPARQL Evaluation Context.

Returns

Type	Description
BaseMultiset

Implements

ISparqlQueryProcessor

ISparqlQueryAlgebraProcessor<TResult, TContext>

Extension Methods

Extensions.ToSafeString(object)

Extensions.AsEnumerable<T>(T)