org.openrdf.sail.federation.optimizers
Class QueryMultiJoinOptimizer

java.lang.Object
  org.openrdf.sail.federation.optimizers.QueryMultiJoinOptimizer

All Implemented Interfaces:

QueryOptimizer

public class QueryMultiJoinOptimizer
extends Object
implements QueryOptimizer

A query optimizer that re-orders nested Joins.

Author:

Arjohn Kampman, James Leigh

Nested Class Summary

protected class

QueryMultiJoinOptimizer.JoinVisitor

Field Summary

protected EvaluationStatistics

statistics

Constructor Summary

QueryMultiJoinOptimizer()

QueryMultiJoinOptimizer(EvaluationStatistics statistics)

Method Summary

void	optimize(TupleExpr tupleExpr, Dataset dataset, BindingSet bindings) Applies generally applicable optimizations: path expressions are sorted from more to less specific.

Methods inherited from class java.lang.Object

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

Field Detail

statistics

protected final EvaluationStatistics statistics

Constructor Detail

QueryMultiJoinOptimizer

public QueryMultiJoinOptimizer()

QueryMultiJoinOptimizer

public QueryMultiJoinOptimizer(EvaluationStatistics statistics)

Method Detail

optimize

public void optimize(TupleExpr tupleExpr,
                     Dataset dataset,
                     BindingSet bindings)

Applies generally applicable optimizations: path expressions are sorted from more to less specific.

Specified by:

optimize in interface QueryOptimizer

Parameters:

query -

Throws:

StoreException