/*
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 Oct 16, 2008
*/
package com.bigdata.relation.rule.eval.pipeline;
import java.io.IOException;
import java.rmi.Remote;
import java.util.UUID;
import com.bigdata.relation.accesspath.IBuffer;
import com.bigdata.relation.rule.eval.ISolution;
/**
* Interface exported by the {@link JoinMasterTask}.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public interface IJoinMaster extends Remote {
/**
* Return a unique identifier for the {@link JoinMasterTask} instance. This
* is used to concentrate all {@link DistributedJoinTask} that target the
* same tail predicate and index partition onto the same
* {@link DistributedJoinTask} sink.
*
* @return The unique identifier.
*/
UUID getUUID() throws IOException;
/**
* A proxy for the buffer on which the last {@link DistributedJoinTask} must
* write its <em>query</em> solutions. Note that mutation operations DO
* NOT use this buffer in order to avoid sending all data through the
* master.
*
* @throws UnsupportedOperationException
* if the operation is not a query.
*/
IBuffer<ISolution[]> getSolutionBuffer() throws IOException;
/**
* Used to send join stats to the master.
*/
void report(JoinStats joinStats) throws IOException;
}