/* Copyright 2008, 2009, 2010 by the Oxford University Computing Laboratory
   
   This file is part of HermiT.

   HermiT 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 3 of the License, or
   (at your option) any later version.
   
   HermiT 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 HermiT.  If not, see <http://www.gnu.org/licenses/>.
*/
package org.semanticweb.HermiT.existentials;

import java.io.Serializable;

import org.semanticweb.HermiT.blocking.BlockingStrategy;
import org.semanticweb.HermiT.model.AtLeast;
import org.semanticweb.HermiT.tableau.Node;

/**
 * Strategy for expanding all existentials on the oldest node in the tableau with unexpanded existentials.
 * This usually closely approximates a breadth-first expansion. (Existentials introduced onto parent nodes
 * as a result of constraints on their children can produce newer nodes of lower depth than older nodes,
 * which could result in slight non-breadth-first behavior.)
 */
public class CreationOrderStrategy extends AbstractExpansionStrategy implements Serializable {
    private static final long serialVersionUID=-64673639237063636L;
    
    public CreationOrderStrategy(BlockingStrategy strategy) {
        super(strategy,true);
    }
    public boolean isDeterministic() {
        return true;
    }
    protected void expandExistential(AtLeast atLeast,Node forNode) {
        m_existentialExpansionManager.expand(atLeast,forNode);
        m_existentialExpansionManager.markExistentialProcessed(atLeast,forNode);
    }
}