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.Config;
22: import gov.nasa.jpf.VM;
23: import gov.nasa.jpf.jvm.TrailInfo;
24:
25: /**
26: * a heuristic state prioritizer that favors certain threads (specified
27: * by thread names during initialization)
28: *
29: * <2do> for both efficiency and encapsulation reasons, this should be just
30: * a Scheduler policy (so that we don't have to expand all children)
31: */
32: public class PreferThreads implements Heuristic {
33: VM vm;
34: String[] preferredThreads;
35:
36: public PreferThreads(Config config, HeuristicSearch hSearch) {
37: vm = hSearch.getVM();
38: preferredThreads = config
39: .getStringArray("search.heuristic.preferredThreads");
40: }
41:
42: public int heuristicValue() {
43: TrailInfo t = (TrailInfo) vm.getLastTransition();
44:
45: if (t == null) {
46: return 1;
47: }
48:
49: String tn = vm.getThreadName();
50:
51: for (int i = 0; i < preferredThreads.length; i++) {
52: if (tn.equals(preferredThreads[i])) {
53: return 0;
54: }
55: }
56:
57: return 1;
58: }
59:
60: public void processParent() {
61: }
62: }
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