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: * helper class to store reference objects
23: * <2do> check how 'isClass' correlates with ClassRef
24: */
25: public abstract class Ref {
26: public static final ObjRef NULL = new ObjRef(-1);
27: int reference;
28: boolean isClass;
29:
30: protected Ref(int r, boolean c) {
31: reference = r;
32: isClass = c;
33: }
34:
35: public boolean isClass() {
36: return isClass;
37: }
38:
39: public boolean isNull() {
40: return reference == -1;
41: }
42:
43: public int getReference() {
44: return reference;
45: }
46:
47: public abstract Object clone();
48:
49: public boolean equals(Object o) {
50: return (reference == ((Ref) o).reference)
51: && (isClass == ((Ref) o).isClass);
52: }
53:
54: public int hashCode() {
55: return reference;
56: }
57:
58: public String toString() {
59: return (isClass ? "@" : "#") + reference;
60: }
61: }
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