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1   /*******************************************************************************
2    * SAT4J: a SATisfiability library for Java Copyright (C) 2004, 2012 Artois University and CNRS
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   * Contributors:
28   *   CRIL - initial API and implementation
29   *******************************************************************************/
30  package org.sat4j.pb.constraints;
31  
32  import org.sat4j.minisat.constraints.cnf.LearntBinaryClause;
33  import org.sat4j.minisat.constraints.cnf.LearntWLClause;
34  import org.sat4j.minisat.constraints.cnf.OriginalBinaryClause;
35  import org.sat4j.minisat.constraints.cnf.OriginalWLClause;
36  import org.sat4j.minisat.constraints.cnf.UnitClause;
37  import org.sat4j.minisat.core.Constr;
38  import org.sat4j.minisat.core.ILits;
39  import org.sat4j.specs.IVecInt;
40  import org.sat4j.specs.UnitPropagationListener;
41  
42  public class UnitBinaryWLClauseConstructor implements IClauseConstructor {
43  
44      public Constr constructClause(UnitPropagationListener solver, ILits voc,
45              IVecInt v) {
46          if (v == null) {
47              // tautological clause
48              return null;
49          }
50          if (v.size() == 1) {
51              return new UnitClause(v.last());
52          }
53          if (v.size() == 2) {
54              return OriginalBinaryClause.brandNewClause(solver, voc, v);
55          }
56          return OriginalWLClause.brandNewClause(solver, voc, v);
57      }
58  
59      public Constr constructLearntClause(ILits voc, IVecInt literals) {
60          if (literals.size() == 1) {
61              return new UnitClause(literals.last());
62          }
63          if (literals.size() == 2) {
64              return new LearntBinaryClause(literals, voc);
65          }
66          return new LearntWLClause(literals, voc);
67      }
68  
69  }