org.topbraid.shacl.expr

Interface NodeExpression

All Known Subinterfaces:

AtomicNodeExpression

All Known Implementing Classes:

AbstractInputExpression, AbstractNodeExpression, AbstractSPARQLExpression, AskExpression, ComplexNodeExpression, ConstantTermExpression, CountExpression, DistinctExpression, ExistsExpression, FilterShapeExpression, FocusNodeExpression, FunctionExpression, GroupConcatExpression, IfExpression, IntersectionExpression, LimitExpression, MaxExpression, MinExpression, MinusExpression, OffsetExpression, OrderByExpression, PathExpression, SelectExpression, SumExpression, UnionExpression

public interface NodeExpression

Interface of all SHACL node expression runtime objects.

Author:

Holger Knublauch

Method Summary

Modifier and Type	Method and Description
org.apache.jena.util.iterator.ExtendedIterator<org.apache.jena.rdf.model.RDFNode>	eval(org.apache.jena.rdf.model.RDFNode focusNode, NodeExpressionContext context) Produces an iterator of value nodes for a given focus node.
org.apache.jena.util.iterator.ExtendedIterator<org.apache.jena.rdf.model.RDFNode>	evalReverse(org.apache.jena.rdf.model.RDFNode valueNode, NodeExpressionContext context) Produces an iterator of focus nodes for a given value node.
String	getFunctionalSyntax() Produces a "functional" syntax used to display node expressions in a compact form.
List<NodeExpression>	getInputExpressions()
org.apache.jena.rdf.model.Resource	getOutputShape(org.apache.jena.rdf.model.Resource contextShape) Gets the shape of the output data (if known), based on a context shape.
org.apache.jena.rdf.model.RDFNode	getRDFNode() Gets the RDF node that was used to construct the expression, in the SHACL node expressions syntax.
String	getTypeId()
boolean	isReversible(NodeExpressionContext context) Checks if this expression could be evaluated in the reverse direction, with a value given and then finding all focus nodes.
void	visit(NodeExpressionVisitor visitor)

Method Detail

eval

org.apache.jena.util.iterator.ExtendedIterator<org.apache.jena.rdf.model.RDFNode> eval(org.apache.jena.rdf.model.RDFNode focusNode,
                                                                                       NodeExpressionContext context)

Produces an iterator of value nodes for a given focus node.

Parameters:

focusNode - the focus node

context - the context

Returns:

an iterator (never null)

evalReverse

org.apache.jena.util.iterator.ExtendedIterator<org.apache.jena.rdf.model.RDFNode> evalReverse(org.apache.jena.rdf.model.RDFNode valueNode,
                                                                                              NodeExpressionContext context)

Produces an iterator of focus nodes for a given value node. This operation can only be called for node expressions where isReversible returns true and may throw an IllegalStateException otherwise.

Parameters:

valueNode - the value node

context - the context

Returns:

an iterator (never null)

getFunctionalSyntax

String getFunctionalSyntax()

Produces a "functional" syntax used to display node expressions in a compact form.

Returns:

the functional syntax for this expression

getInputExpressions

List<NodeExpression> getInputExpressions()

getOutputShape

org.apache.jena.rdf.model.Resource getOutputShape(org.apache.jena.rdf.model.Resource contextShape)

Gets the shape of the output data (if known), based on a context shape. For example, for a path expression it would try to infer the output shape from the sh:class or sh:node of the property (path).

Parameters:

contextShape - the shape where the evaluation would start, e.g. the node shape of the sh:values statement

Returns:

an output shape or null if unknown

getRDFNode

org.apache.jena.rdf.model.RDFNode getRDFNode()

Gets the RDF node that was used to construct the expression, in the SHACL node expressions syntax.

Returns:

the RDF node

getTypeId

String getTypeId()

isReversible

boolean isReversible(NodeExpressionContext context)

Checks if this expression could be evaluated in the reverse direction, with a value given and then finding all focus nodes. The function evalReverse can then be called. NOTE THAT THIS IS CURRENTLY BARELY IMPLEMENTED.

Parameters:

context - the context

Returns:

true if reversible

visit

void visit(NodeExpressionVisitor visitor)