1 /******************************************************************************* 2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre 3 * 4 * All rights reserved. This program and the accompanying materials 5 * are made available under the terms of the Eclipse Public License v1.0 6 * which accompanies this distribution, and is available at 7 * http://www.eclipse.org/legal/epl-v10.html 8 * 9 * Alternatively, the contents of this file may be used under the terms of 10 * either the GNU Lesser General Public License Version 2.1 or later (the 11 * "LGPL"), in which case the provisions of the LGPL are applicable instead 12 * of those above. If you wish to allow use of your version of this file only 13 * under the terms of the LGPL, and not to allow others to use your version of 14 * this file under the terms of the EPL, indicate your decision by deleting 15 * the provisions above and replace them with the notice and other provisions 16 * required by the LGPL. If you do not delete the provisions above, a recipient 17 * may use your version of this file under the terms of the EPL or the LGPL. 18 * 19 * Based on the original MiniSat specification from: 20 * 21 * An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the 22 * Sixth International Conference on Theory and Applications of Satisfiability 23 * Testing, LNCS 2919, pp 502-518, 2003. 24 * 25 * See www.minisat.se for the original solver in C++. 26 * 27 *******************************************************************************/ 28 package org.sat4j.minisat.core; 29 30 /** 31 * Interface providing the unit propagation capability. 32 * 33 * @author leberre 34 */ 35 public interface UnitPropagationListener { 36 37 /** 38 * satisfies a literal 39 * 40 * @param p 41 * a literal 42 * @return true if the assignment looks possible, false if a conflict 43 * occurs. 44 */ 45 public abstract boolean enqueue(int p); 46 47 /** 48 * satisfies a literal 49 * 50 * @param p 51 * a literal 52 * @param from 53 * a reason explaining why p should be satisfied. 54 * @return true if the assignment looks possible, false if a conflict 55 * occurs. 56 */ 57 public abstract boolean enqueue(int p, Constr from); 58 59 /** 60 * Unset a unit clause. The effect of such method is to unset all truth 61 * values on the stack until the given literal is found (that literal 62 * included). 63 * 64 * @param p 65 * @since 2.1 66 */ 67 public void unset(int p); 68 }