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

Class ProjectionRemovalOptimizer

java.lang.Object

org.eclipse.rdf4j.query.algebra.evaluation.optimizer.ProjectionRemovalOptimizer

org.eclipse.rdf4j.query.algebra.evaluation.impl.ProjectionRemovalOptimizer

All Implemented Interfaces:

QueryOptimizer

@Deprecated(forRemoval=true,
            since="4.1.0")
public class ProjectionRemovalOptimizer
extends ProjectionRemovalOptimizer
implements QueryOptimizer

Deprecated, for removal: This API element is subject to removal in a future version.

since 4.1.0. Use ProjectionRemovalOptimizer instead.

If a projection node in the algebra does not contribute or change the results it can be removed from the tree.

For example SELECT ?s ?p ?o WHERE {?s ?p ?o } Does not need a projection as the inner statement pattern returns the same result.

While * SELECT ?s ?p WHERE {?s ?p ?o } Does as the statement pattern has one more variable in use than the projection.

Note: this optimiser should run after optimisations ran that depend on Projections. e.g.

Author:

Jerven Bolleman

See Also:

• UnionScopeChangeOptimizer

Constructor Summary

Constructors

Constructor	Description
ProjectionRemovalOptimizer()	Deprecated, for removal: This API element is subject to removal in a future version.

Method Summary

Methods inherited from class org.eclipse.rdf4j.query.algebra.evaluation.optimizer.ProjectionRemovalOptimizer

optimize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.eclipse.rdf4j.query.algebra.evaluation.QueryOptimizer

optimize

Constructor Details

ProjectionRemovalOptimizer

public ProjectionRemovalOptimizer()

Deprecated, for removal: This API element is subject to removal in a future version.