1 /*
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2006 Daniel Le Berre
3 *
4 * Based on the original minisat specification from:
5 *
6 * An extensible SAT solver. Niklas E?n and Niklas S?rensson. Proceedings of the
7 * Sixth International Conference on Theory and Applications of Satisfiability
8 * Testing, LNCS 2919, pp 502-518, 2003.
9 *
10 * This library is free software; you can redistribute it and/or modify it under
11 * the terms of the GNU Lesser General Public License as published by the Free
12 * Software Foundation; either version 2.1 of the License, or (at your option)
13 * any later version.
14 *
15 * This library is distributed in the hope that it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
17 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * details.
19 *
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with this library; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 */
25
26 package org.sat4j.minisat.core;
27
28 /**
29 * Interface providing the unit propagation capability.
30 *
31 * @author leberre
32 */
33 public interface UnitPropagationListener {
34
35 /**
36 * satisfies a literal
37 *
38 * @param p
39 * a literal
40 * @return true if the assignment looks possible, false if a conflict
41 * occurs.
42 */
43 public abstract boolean enqueue(int p);
44
45 /**
46 * satisfies a literal
47 *
48 * @param p
49 * a literal
50 * @param from
51 * a reason explaining why p should be satisfied.
52 * @return true if the assignment looks possible, false if a conflict
53 * occurs.
54 */
55 public abstract boolean enqueue(int p, Constr from);
56 }