org.eclipse.rdf4j.federated.optimizer

Class LimitOptimizer

java.lang.Object

org.eclipse.rdf4j.query.algebra.helpers.AbstractQueryModelVisitor<OptimizationException>

org.eclipse.rdf4j.federated.optimizer.LimitOptimizer

All Implemented Interfaces:

FedXOptimizer, QueryModelVisitor<OptimizationException>

public class LimitOptimizer
extends AbstractQueryModelVisitor<OptimizationException>
implements FedXOptimizer

An optimizer that attempts to push upper limits into BGPs of the query. Currently upper limits are only pushed for simple queries consisting of a single BGP.

Author:

Andreas Schwarte

Constructor Summary

Constructors

Constructor and Description
LimitOptimizer()

Method Summary

Modifier and Type	Method and Description
void	meet(Projection proj)
void	meet(Slice node)
void	meetOther(QueryModelNode node)
void	optimize(TupleExpr tupleExpr) Optimize the provided tuple expression
protected void	pushLimit(FedXStatementPattern stmt, long upperLimit)

Methods inherited from class org.eclipse.rdf4j.query.algebra.helpers.AbstractQueryModelVisitor

meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meetBinaryTupleOperator, meetBinaryValueOperator, meetCompareSubQueryValueOperator, meetNAryValueOperator, meetNode, meetSubQueryValueOperator, meetUnaryTupleOperator, meetUnaryValueOperator, meetUpdateExpr

Methods inherited from class java.lang.Object

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

Constructor Detail

LimitOptimizer

public LimitOptimizer()

Method Detail

optimize

public void optimize(TupleExpr tupleExpr)

Description copied from interface: FedXOptimizer

Optimize the provided tuple expression

Specified by:

optimize in interface FedXOptimizer

meetOther

public void meetOther(QueryModelNode node)
               throws OptimizationException

Specified by:

meetOther in interface QueryModelVisitor<OptimizationException>

Overrides:

meetOther in class AbstractQueryModelVisitor<OptimizationException>

Throws:

OptimizationException

meet

public void meet(Slice node)
          throws OptimizationException

Specified by:

meet in interface QueryModelVisitor<OptimizationException>

Overrides:

meet in class AbstractQueryModelVisitor<OptimizationException>

Throws:

OptimizationException

meet

public void meet(Projection proj)
          throws OptimizationException

Specified by:

meet in interface QueryModelVisitor<OptimizationException>

Overrides:

meet in class AbstractQueryModelVisitor<OptimizationException>

Throws:

OptimizationException

pushLimit

protected void pushLimit(FedXStatementPattern stmt,
                         long upperLimit)