/*
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 Jun 26, 2008
*/
package com.bigdata.bop.joinGraph;
import com.bigdata.relation.rule.IRule;
/**
* Interface for evaluation orders.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public interface IEvaluationPlan {
/**
* Return the evaluation order.
*
* @return The evaluation order. This is an array of indices into the
* predicates in the tail of the rule. Each tail predicate must be
* used exactly once. The elements in this array are the order in
* which each tail predicate will be evaluated. The index into the
* array is the index of the tail predicate whose evaluation order
* you want. So <code>[2,0,1]</code> says that the predicates will
* be evaluated in the order tail[2], then tail[0], then tail[1].
*/
public int[] getOrder();
/**
* <code>true</code> iff the {@link IRule} was proven to be empty based on
* range counts or other data.
*/
public boolean isEmpty();
/**
* The range count for the predicate.
*
* @param tailIndex
* The index of the predicate in the tail of the rule.
*
* @return The range count for that predicate.
*
* @see IRangeCountFactory
*/
public long rangeCount(int tailIndex);
}