/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Sep 15, 2011
*/
package com.bigdata.rdf.sparql.ast.optimizers;
import com.bigdata.bop.IBindingSet;
import com.bigdata.rdf.sparql.ast.IQueryNode;
import com.bigdata.rdf.sparql.ast.JoinGroupNode;
import com.bigdata.rdf.sparql.ast.QueryNodeWithBindingSet;
import com.bigdata.rdf.sparql.ast.StaticAnalysis;
import com.bigdata.rdf.sparql.ast.eval.AST2BOpContext;
/**
* Lift FILTERs which can be evaluated based solely on the bindings in the
* parent group out of a child group. This helps because we will issue the
* subquery for the child group less often (assuming that the filter rejects any
* solutions). This optimizer is based on
* {@link StaticAnalysis#getPreFilters(JoinGroupNode)}. Anything reported by
* that method can be lifted out of the child group.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id: ASTLiftPreFiltersOptimizer.java 5193 2011-09-15 14:18:56Z
* thompsonbry $
*
* FIXME Implement.
*/
public class ASTLiftPreFiltersOptimizer implements IASTOptimizer {
@Override
public QueryNodeWithBindingSet optimize(
final AST2BOpContext context, final QueryNodeWithBindingSet input) {
final IQueryNode queryNode = input.getQueryNode();
final IBindingSet[] bindingSets = input.getBindingSets();
return new QueryNodeWithBindingSet(queryNode, bindingSets);
}
}