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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 java.io.Serializable;
31  
32  /**
33   * Abstraction allowing to choose various restarts strategies.
34   * 
35   * @author leberre
36   *
37   */
38  public interface RestartStrategy extends Serializable {
39  
40      /**
41       * Hook method called just before the search starts.
42       * @param params the user's search parameters.
43       *
44       */
45      void init(SearchParams params);
46      
47      /**
48       * Ask for the next restart in number of conflicts.
49       * 
50       * @return the delay in conflicts before the next restart.
51       */
52      long nextRestartNumberOfConflict();
53      
54      /**
55       * Hook method called when a restart occurs (once the solver 
56       * has backtracked to top decision level).
57       *
58       */
59      void onRestart();
60  }