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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.orders;
29  
30  /**
31   * Utility class used to order the literals according to a specific heuristics.
32   * 
33   */
34  final class ValuedLit implements Comparable<ValuedLit> {
35  	final int id;
36  
37  	final int count;
38  
39  	ValuedLit(int id, int count) {
40  		this.id = id;
41  		this.count = count;
42  	}
43  
44  	public int compareTo(ValuedLit t) {
45  		if (count == 0) {
46  			return Integer.MAX_VALUE;
47  		}
48  		if (t.count == 0) {
49  			return -1;
50  		}
51  		return count - t.count;
52  	}
53  
54  	@Override
55  	public boolean equals(Object o) {
56  		if (o == null)
57  			return false;
58  		if (o instanceof ValuedLit) {
59  			return ((ValuedLit) o).count == count;
60  		}
61  		return false;
62  	}
63  
64  	@Override
65  	public int hashCode() {
66  		return id;
67  	}
68  
69  	@Override
70  	public String toString() {
71  		return "" + id + "(" + count + ")"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
72  	}
73  }