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 import org.sat4j.specs.IConstr;
31
32 /**
33 * An assertingClauseGenerator is responsible for the creation of an asserting
34 * clause during conflict analysis. An asserting clause is a clause that will
35 * become unit when the solver will backtrack to the latest decision level,
36 * providing a nice way for the solver to backtrack.
37 *
38 * @author leberre
39 */
40 public interface AssertingClauseGenerator {
41
42 /**
43 * hook method called before the analysis.
44 */
45 void initAnalyze();
46
47 /**
48 * hook method called when a literal from the current decision lelvel is
49 * found.
50 *
51 * @param p
52 * the literal in the current decision level
53 */
54 void onCurrentDecisionLevelLiteral(int p);
55
56 /**
57 * method indicating if an asserting clause has been built. note that this
58 * method is called right after a resolution step is finished.
59 *
60 * @param reason
61 * the reason of the current literal assignment
62 * @return false iff the current clause is assertive
63 */
64 boolean clauseNonAssertive(IConstr reason);
65 }