QueryValueEvaluationStep.ConstantQueryValueEvaluationStep (Eclipse RDF4J 4.3.2)

java.lang.Object
- org.eclipse.rdf4j.query.algebra.evaluation.QueryValueEvaluationStep.ConstantQueryValueEvaluationStep

All Implemented Interfaces:

QueryValueEvaluationStep

Enclosing interface:

QueryValueEvaluationStep
```
public static class QueryValueEvaluationStep.ConstantQueryValueEvaluationStep
extends Object
implements QueryValueEvaluationStep
```
A QueryValueEvalationStep that will return the same constant value throughout the query execution. As these rather result just in a value we set the value at precompile time.

Nested Class Summary
- Nested classes/interfaces inherited from interface org.eclipse.rdf4j.query.algebra.evaluation.QueryValueEvaluationStep
  QueryValueEvaluationStep.ApplyFunctionForEachBinding, QueryValueEvaluationStep.ConstantQueryValueEvaluationStep, QueryValueEvaluationStep.Fail, QueryValueEvaluationStep.Minimal

Constructor Summary

Constructors
Constructor Description

ConstantQueryValueEvaluationStep(Value valueConstant)

ConstantQueryValueEvaluationStep(ValueConstant valueConstant)

Method Summary

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

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ConstantQueryValueEvaluationStep
```
public ConstantQueryValueEvaluationStep(ValueConstant valueConstant)
```
  - ConstantQueryValueEvaluationStep
```
public ConstantQueryValueEvaluationStep(Value valueConstant)
```
- Method Detail
  - evaluate
```
public Value evaluate(BindingSet bindings)
               throws QueryEvaluationException
```
    Specified by:
    
    evaluate in interface QueryValueEvaluationStep
    
    Throws:
    
    QueryEvaluationException
  - isConstant
```
public boolean isConstant()
```
    Description copied from interface: QueryValueEvaluationStep
    
    If an value expression results in a constant then it may be executed once per query invocation. This can reduce computation time significantly.
    
    Specified by:
    
    isConstant in interface QueryValueEvaluationStep
    
    Returns:
    
    if this ValueExpresionStep will always return the same value