01: //
02: // Copyright (C) 2005 United States Government as represented by the
03: // Administrator of the National Aeronautics and Space Administration
04: // (NASA). All Rights Reserved.
05: //
06: // This software is distributed under the NASA Open Source Agreement
07: // (NOSA), version 1.3. The NOSA has been approved by the Open Source
08: // Initiative. See the file NOSA-1.3-JPF at the top of the distribution
09: // 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:
23: /**
24: * Heuristic state prioritizer that favors executions that are not
25: * nondeterministic, i.e. deterministic. When analysing abstracted programs
26: * this has the effect of prioritizing "must"-transitions over "may"-transitions.
27: * An error detected using this heuristic has a good likelihood of being non-spurious.
28: */
29: public class ChooseFree implements Heuristic {
30: VM vm;
31:
32: public ChooseFree(HeuristicSearch hSearch) {
33: vm = hSearch.getVM();
34: }
35:
36: public int heuristicValue() {
37: int h_value = 1 + vm
38: .getAbstractionNonDeterministicThreadCount();
39:
40: return h_value;
41: }
42:
43: public void processParent() {
44: }
45: }
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