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.jvm;
20:
21: /**
22: * the rather thin root class of all scheduler implementations
23: */
24: public abstract class Scheduler implements Cloneable {
25: public abstract int getRandom();
26:
27: public abstract int getThread();
28:
29: public Object clone() {
30: try {
31: return super .clone();
32: } catch (CloneNotSupportedException cnsx) {
33: // silly compiler, can't happen since we implement Cloneable
34: }
35:
36: return null;
37: }
38:
39: public abstract void initialize();
40:
41: public abstract ThreadInfo locateThread(SystemState ss);
42:
43: public abstract void next();
44:
45: // <2do> - how does this differ from getRandom() ? Do we need both ?
46: public abstract int random(int max);
47:
48: // <2do> pcm - factorized VirtualMachine.forward()
49: // (not sure if this doesn't just cover a bug)
50: void checkNext(SystemState ss) {
51: // default does nothing
52: }
53: }
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