/**
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 Jan 26, 2007
*/
package com.bigdata.striterator;
import java.util.Comparator;
import com.bigdata.bop.IElement;
import com.bigdata.bop.IPredicate;
import com.bigdata.btree.keys.IKeyBuilder;
/**
* An interface representing the natural traversal orders for the different
* indices for some class of relation.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
* @param <E>
* The generic type of the elements in the relation.
*/
public interface IKeyOrder<E> {
/**
* Return the #of elements in the key for this natural order.
*/
int getKeyArity();
/**
* Return the comparator that places elements into the natural order for the
* associated index.
*/
Comparator<E> getComparator();
/**
* The base name for the index.
*/
String getIndexName();
/**
* Return the index of the slot in the {@link IPredicate} which appears at
* the specified position in the key.
*
* @param keyPos
* The index into the key that is being generated.
*
* @return The index of the slot in the {@link IPredicate}.
*/
int getKeyOrder(final int keyPos);
/*
* New methods.
*/
/**
* Return the key for an element of the relation.
*
* @param keyBuilder
* The object which will be used to construct the key.
* @param element
* An element for the associated relation.
*
* @return The key for the index associated with this {@link IKeyOrder}.
*
* @todo DDL: This does not really let you handle something which does not
* implement {@link IElement} without overriding
* {@link #getKey(IKeyBuilder, Object)}.
* <p>
* We should have named based access to the "elements" of a relation
* based on a schema (DDL) but also support schema flexible access for
* GOM. (RDF is a fixed schema in this sense with {s,p,o,c}
* properties).
* <p>
* We will also need to support name-based {@link IPredicate}s in
* order to work with GOM.
*/
byte[] getKey(IKeyBuilder keyBuilder, E element);
/**
* Return the inclusive lower bound which would be used for a query against
* this {@link IKeyOrder} for the given {@link IPredicate}.
*
* @param keyBuilder
* The object which will be used to construct the key.
* @param predicate
* A predicate describing bound and unbound fields for the key.
*
* @return The key corresponding to the inclusive lower bound for a query
* against that {@link IPredicate}.
*/
byte[] getFromKey(IKeyBuilder keyBuilder, IPredicate<E> predicate);
/**
* Return the exclusive upper bound which would be used for a query against
* this {@link IKeyOrder} for the given {@link IPredicate}.
*
* @param keyBuilder
* The object which will be used to construct the key.
* @param predicate
* A predicate describing bound and unbound fields for the key.
*
* @return The key corresponding to the exclusive upper bound for a query
* against that {@link IPredicate}.
*/
byte[] getToKey(IKeyBuilder keyBuilder, IPredicate<E> predicate);
}