/*
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
*/
package com.bigdata.rdf.internal.constraints;
/**
* Some {@link IVValueExpression} need materialized terms to perform their
* evaluation. Those that do can implement this interface, and specify which
* terms they need materialized.
*/
public interface INeedsMaterialization {
public enum Requirement {
/**
* Always needs materialization.
*/
ALWAYS,
/**
* Only needs materialization if inline evaluation fails.
*/
SOMETIMES,
/**
* Never needs materialization.
*/
NEVER
};
/**
* Does the bop always need materialized variables, or can it sometimes
* operate on inline terms without materialization? If sometimes, we'll
* run it before the materialization pipeline steps in an effort to avoid
* unnecessary materialization overhead. If it fails to evaluate for a
* particular solution, then it will be run again after the materialization
* steps for that solution.
*/
Requirement getRequirement();
}