/*

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 30, 2007
 */

package com.bigdata.rdf.spo;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

import com.bigdata.relation.accesspath.IBuffer;

/**
 * A buffer for {@link SPO}s. {@link ISPOBuffer}s are used to collect
 * {@link SPO}s into chunks that can be sorted in order to support efficient
 * batch operations on statement indices.
 * 
 * @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
 * @version $Id$
 * 
 * @deprecated by {@link IBuffer}
 */
public interface ISPOBuffer {

    final public Logger log = Logger.getLogger(ISPOBuffer.class);

    /**
     * True iff the {@link #log} level is INFO or less.
     */
    final public boolean INFO = log.getEffectiveLevel().toInt() <= Level.INFO
            .toInt();

    /**
     * True iff the {@link #log} level is DEBUG or less.
     */
    final public boolean DEBUG = log.getEffectiveLevel().toInt() <= Level.DEBUG
            .toInt();

    /**
     * The #of statements currently in the buffer.
     */
    public int size();

    /**
     * True iff there are no statements in the buffer.
     */
    public boolean isEmpty();

    /**
     * Adds an {@link ISPO}.
     * 
     * @param spo
     *            The {@link ISPO}.
     * 
     * @return true if the buffer will store the statement (i.e., the statement
     *         is not excluded by the filter).
     */
    public boolean add(ISPO spo);

    /**
     * Flush any buffered statements to the backing store.
     * 
     * @return The cumulative #of statements that were written on the indices
     *         since the last time the counter was reset. A statement that was
     *         previously an axiom or inferred and that is converted to an
     *         explicit statement by this method will be reported in this count
     *         as well as any statement that was not pre-existing in the
     *         database. Statement removal also counts as a "write".
     * 
     * @see #flush(boolean)
     */
    public int flush();
    
}