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Java > Open Source Codes > gov > nasa > jpf > search > heuristic > UserHeuristic


1 //
2 // Copyright (C) 2005 United States Government as represented by the
3 // Administrator of the National Aeronautics and Space Administration
4 // (NASA). All Rights Reserved.
5 //
6 // This software is distributed under the NASA Open Source Agreement
7 // (NOSA), version 1.3. The NOSA has been approved by the Open Source
8 // Initiative. See the file NOSA-1.3-JPF at the top of the distribution
9 // directory tree for the complete NOSA document.
10 //
11 // THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
12 // KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
13 // LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
14 // SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
15 // A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
16 // THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
17 // DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
18 //
19 package gov.nasa.jpf.search.heuristic;
20
21 import gov.nasa.jpf.VM;
22 import gov.nasa.jpf.jvm.JVM;
23 import gov.nasa.jpf.jvm.Reference;
24 import gov.nasa.jpf.jvm.SystemState;
25
26
27 /**
28  * heuristic state prioritizer that uses fields of the Main class uner test
29  * to determine priorities (i.e. priorities can be set by the program under test)
30  *
31  * <2do> pcm - does this still make sense in light of MJI ? If we keep it, this
32  * has tobe moved to the Verify interface!
33  */
34 public class UserHeuristic implements Heuristic {
35   static final int defaultValue = 1000;
36   VM vm;
37
38   public UserHeuristic (HeuristicSearch hSearch) {
39     vm = hSearch.getVM();
40   }
41
42   public int heuristicValue () {
43     // <2do> pcm - BAD, remove the VM nuts-and-bolts dependencies
44 SystemState ss = (SystemState) ((JVM) vm).getSystemState();
45     Reference p = ss.getClass("Main");
46
47     if (p != null) {
48       Reference b = p.getObjectField("buffer", null);
49
50       if (b != null) {
51         int current = b.getIntField("current", null);
52         int capacity = b.getIntField("capacity", null);
53
54         return (capacity - current);
55       }
56     }
57
58     return defaultValue;
59   }
60
61   public void processParent () {
62   }
63 }
64
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