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Java > Open Source Codes > gov > nasa > jpf > jvm > Scheduler


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.jvm;
20
21 /**
22  * the rather thin root class of all scheduler implementations
23  */
24 public abstract class Scheduler implements Cloneable JavaDoc {
25   public abstract int getRandom ();
26
27   public abstract int getThread ();
28
29   public Object JavaDoc clone () {
30     try {
31       return super.clone();
32     } catch (CloneNotSupportedException JavaDoc 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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