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 import org.sat4j.specs.IConstr;
29
30 /**
31 * An assertingClauseGenerator is responsible for the creation of an asserting
32 * clause during conflict analysis. An asserting clause is a clause that will
33 * become unit when the solver will backtrack to the latest decision level,
34 * providing a nice way for the solver to backtrack.
35 *
36 * @author leberre
37 */
38 public interface AssertingClauseGenerator {
39
40 /**
41 * hook method called before the analysis.
42 */
43 void initAnalyze();
44
45 /**
46 * hook method called when a literal from the current decision lelvel is
47 * found.
48 *
49 * @param p
50 * the literal in the current decision level
51 */
52 void onCurrentDecisionLevelLiteral(int p);
53
54 /**
55 * method indicating if an asserting clause has been built. note that this
56 * method is called right after a resolution step is finished.
57 *
58 * @param reason
59 * the reason of the current literal assignment
60 * @return false iff the current clause is assertive
61 */
62 boolean clauseNonAssertive(IConstr reason);
63 }