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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;
31  
32  import java.util.ArrayList;
33  import java.util.List;
34  
35  public class DepdendenyNode<C> {
36      private final C name;
37      private List<DepdendenyNode<C>> children;
38      private final Explanation<C> explanation;
39  
40      public DepdendenyNode(C name, Explanation<C> explanation) {
41          this.name = name;
42          this.explanation = explanation;
43      }
44  
45      public C getName() {
46          return this.name;
47      }
48  
49      public DepdendenyNode<C> newChild(C name) {
50          DepdendenyNode<C> newNode = this.explanation.newNode(name);
51          if (this.children == null) {
52              this.children = new ArrayList<DepdendenyNode<C>>();
53          }
54          this.children.add(newNode);
55          return newNode;
56      }
57  
58      public boolean hasBranches() {
59          if (this.children == null || this.children.isEmpty()) {
60              return false;
61          }
62          if (this.children.size() > 1) {
63              return true;
64          }
65          return this.children.get(0).hasBranches();
66      }
67  
68      public int getMaxDepth() {
69          if (this.children == null || this.children.isEmpty()) {
70              return 1;
71          }
72          int maxChildDepth = 0;
73          for (DepdendenyNode<C> child : this.children) {
74              int childDepth = child.getMaxDepth();
75              if (childDepth > maxChildDepth) {
76                  maxChildDepth = childDepth;
77              }
78          }
79          return maxChildDepth + 1;
80      }
81  
82      public DepdendenyNode<C> getOnlyChild() {
83          if (this.children == null || this.children.isEmpty()) {
84              return null;
85          }
86          if (this.children.size() > 1) {
87              throw new IllegalStateException(this + " has "
88                      + this.children.size() + " children.");
89          }
90          return this.children.get(0);
91      }
92  }