/*
 * Copyright (C) 2003-2004 Red Hat Inc. All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
package com.redhat.persistence;

import com.redhat.persistence.oql.Expression;
import java.util.Map;


/**
 * Engine
 *
 * @author Rafael H. Schloming &lt;rhs@mit.edu&gt;
 * @version $Revision: #7 $ $Date: 2004/08/16 $
 **/

public abstract class Engine {

    public final static String versionId = "$Id: Engine.java 1045 2005-12-09 13:41:22Z sskracic $ by $Author: sskracic $, $DateTime: 2004/08/16 18:10:38 $";

    private Session m_ssn;

    void setSession(Session ssn) {
        m_ssn = ssn;
    }

    public Session getSession() {
        return m_ssn;
    }

    protected abstract void write(Event ev);
    protected abstract void flush();
    protected abstract void rollback();
    protected abstract void commit();
    protected abstract RecordSet execute(Signature sig, Expression expr);
    protected abstract RecordSet execute(Signature sig, Expression expr, Map options);
    protected abstract long size(Expression expr);

}
