org.openrdf.query.algebra.evaluation.impl
Class SameTermFilterOptimizer

java.lang.Object
  org.openrdf.query.algebra.evaluation.impl.SameTermFilterOptimizer

All Implemented Interfaces:

QueryOptimizer

public class SameTermFilterOptimizer
extends Object
implements QueryOptimizer

A query optimizer that embeds Filters with SameTerm operators in statement patterns as much as possible. Operators like sameTerm(X, Y) are processed by renaming X to Y (or vice versa). Operators like sameTerm(X, ) are processed by assigning the URI to all occurrnig variables with name X.

Author:

Arjohn Kampman

Nested Class Summary

protected class	SameTermFilterOptimizer.SameTermFilterVisitor
protected class	SameTermFilterOptimizer.VarBinder
protected class	SameTermFilterOptimizer.VarRenamer

Constructor Summary

SameTermFilterOptimizer()

Method Summary

void	optimize(TupleExpr tupleExpr, Dataset dataset, BindingSet bindings) Applies generally applicable optimizations to the supplied query: variable assignments are inlined.

Methods inherited from class java.lang.Object

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

Constructor Detail

SameTermFilterOptimizer

public SameTermFilterOptimizer()

Method Detail

optimize

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

Applies generally applicable optimizations to the supplied query: variable assignments are inlined.

Specified by:

optimize in interface QueryOptimizer

Parameters:

tupleExpr -

Throws:

QueryEvaluationException