package org.sat4j.minisat.constraints.cnf;

import org.sat4j.minisat.core.ILits;
import org.sat4j.minisat.core.UnitPropagationListener;
import org.sat4j.specs.IVecInt;

/*******************************************************************************
* SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU Lesser General Public License Version 2.1 or later (the
* "LGPL"), in which case the provisions of the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of the LGPL, and not to allow others to use your version of
* this file under the terms of the EPL, indicate your decision by deleting
* the provisions above and replace them with the notice and other provisions
* required by the LGPL. If you do not delete the provisions above, a recipient
* may use your version of this file under the terms of the EPL or the LGPL.
* 
* Based on the original MiniSat specification from:
* 
* An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
* Sixth International Conference on Theory and Applications of Satisfiability
* Testing, LNCS 2919, pp 502-518, 2003.
*
* See www.minisat.se for the original solver in C++.
* 
*******************************************************************************/
public class OriginalBinaryClause extends BinaryClause {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public OriginalBinaryClause(IVecInt ps, ILits voc) {
		super(ps, voc);
	}

	public void setLearnt() {
		// do nothing
	}

	public boolean learnt() {
		return false;
	}

    /**
     * Creates a brand new clause, presumably from external data.
     * 
     * @param s
     *            the object responsible for unit propagation
     * @param voc
     *            the vocabulary
     * @param literals
     *            the literals to store in the clause
     * @return the created clause or null if the clause should be ignored
     *         (tautology for example)
     */
    public static OriginalBinaryClause brandNewClause(UnitPropagationListener s,
            ILits voc, IVecInt literals) {
        OriginalBinaryClause c = new OriginalBinaryClause(literals, voc);
        c.register();
        return c;
    }
}