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


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 import java.util.Hashtable JavaDoc;
22
23
24 /**
25  * analogy of DynamicMap to achieve symmetry for static fields (sp that order
26  * of class init does not matter)
27  */
28 public class StaticMap {
29   static Hashtable JavaDoc mapping = new Hashtable JavaDoc();
30   static int counter = 0;
31
32   public static int getEntry (String JavaDoc cname) {
33     return ((Integer JavaDoc) mapping.get(cname)).intValue();
34   }
35
36   public static int addEntry (String JavaDoc cname) {
37     Integer JavaDoc index = (Integer JavaDoc) mapping.get(cname);
38
39     if (index != null) {
40       return index.intValue();
41     }
42     synchronized (StaticMap.class) {
43       index = (Integer JavaDoc) mapping.get(cname);
44
45       if (index != null) {
46         return index.intValue();
47       }
48
49       mapping.put(cname, new Integer JavaDoc(counter));
50
51       return counter++;
52     }
53   }
54
55   public static boolean hasEntry (String JavaDoc cname) {
56     return mapping.containsKey(cname);
57   }
58
59   public static synchronized void init () {
60     mapping = new Hashtable JavaDoc();
61     counter = 0;
62   }
63 }
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