com.bigdata.relation.accesspath.IAbstractAccessPath Maven / Gradle / Ivy
/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
[email protected]
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 28, 2011
*/
package com.bigdata.relation.accesspath;
import com.bigdata.bop.IPredicate;
import com.bigdata.btree.IRangeQuery;
import com.bigdata.relation.IRelation;
import cutthecrap.utils.striterators.IFilter;
/**
* A common interface for all access paths.
*
* @param
* The generic type of the [R]elation elements of the
* {@link IRelation}.
*
* @author Bryan Thompson
* @version $Id$
*/
public interface IAbstractAccessPath {
/**
* The constraints on the {@link IAccessPath}.
*/
IPredicate getPredicate();
/**
* True iff the access path is empty (there are no matches for the
* {@link IPredicate}) This is more conclusive than {@link #rangeCount()}
* since you MAY have a non-zero range count when the key range is in fact
* empty (there may be "deleted" index entries within the key range).
*/
boolean isEmpty();
/**
* Return the maximum #of elements spanned by the {@link IPredicate}.
*
* Note: When there is an {@link IFilter} on the {@link IPredicate} the
* exact range count MUST apply that {@link IFilter}, which means that it
* will be required to traverse the index counting tuples which pass the
* {@link IFilter}. However, {@link IFilter}s are ignored for the fast
* range count.
*
* @param exact
* When true, the result will be an exact count and
* may require a key-range scan. When false, the
* result will be an upper bound IFF delete markers are
* provisioned for the backing index (delete markers are required
* for transactions and for scale-out indices).
*
* @see IRangeQuery
*/
long rangeCount(boolean exact);
/**
* Remove all elements selected by the {@link IPredicate} (optional
* operation).
*
* @return The #of elements that were removed.
*/
public long removeAll();
}