Package org.eclipse.rdf4j.query.algebra.evaluation

Interface QueryValueEvaluationStep

All Known Implementing Classes:

AndValueEvaluationStep, CompareAllQueryValueEvaluationStep, CompareAnyValueEvaluationStep, ExistsQueryValueEvaluationStep, IfValueEvaluationStep, InValueEvaluationStep, ListMemberValueOperationStep, OrValueEvaluationStep, QueryValueEvaluationStep.ApplyFunctionForEachBinding, QueryValueEvaluationStep.ConstantQueryValueEvaluationStep, QueryValueEvaluationStep.Fail, QueryValueEvaluationStep.Minimal, ValueExprTripleRefEvaluationStep

public interface QueryValueEvaluationStep

A step in the query evaluation that works on ValueExpresions.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	QueryValueEvaluationStep.ApplyFunctionForEachBinding	A minimal implementation that falls calls a function that should return a value per passed in bindingsets.
static class	QueryValueEvaluationStep.ConstantQueryValueEvaluationStep	A QueryValueEvalationStep that will return the same constant value throughout the query execution.
static final class	QueryValueEvaluationStep.Fail	A minimal implementation that falls is known to throw an ValueExprEvaluationException.
static final class	QueryValueEvaluationStep.Minimal	A minimal implementation that falls back to calling evaluate in the strategy.

Method Summary

Modifier and Type	Method	Description
Value	evaluate(BindingSet bindings)
default boolean	isConstant()	If an value expression results in a constant then it may be executed once per query invocation.

Method Details

evaluate

Value evaluate(BindingSet bindings)
        throws QueryEvaluationException

Throws:

QueryEvaluationException

isConstant

default boolean isConstant()

If an value expression results in a constant then it may be executed once per query invocation. This can reduce computation time significantly.

Returns:

if this ValueExpresionStep will always return the same value