/*
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 Aug 20, 2008
*/
package com.bigdata.bop.joinGraph;
import com.bigdata.bop.IPredicate;
import com.bigdata.relation.rule.IRule;
/**
* An interface used by an {@link IEvaluationPlan} to obtain range counts for
* the {@link IPredicate}s in an {@link IRule}. The use of this interface on
* the one hand makes it possible to test {@link IEvaluationPlan}s without real
* data and on the other hand makes it possible to cache range counts across
* queries evaluated against the same state of the database.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public interface IRangeCountFactory {
/**
* Return the range count for the predicate as bound. For indices that use
* delete markers this will be an upper bound NOT an exact range count.
* However, if the range count is reported as ZERO (0L) as an upper bound
* this still indicates that there are no solutions for that predicate in
* the data.
*
* @param pred
* The predicate.
*
* @return The range count.
*/
public long rangeCount(IPredicate pred);
}