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1
4 package gnu.kawa.reflect;
5 import gnu.bytecode.*;
6 import gnu.mapping.*;
7 import gnu.expr.*;
8
9 public class SingletonType extends ObjectType {
11 static final SingletonType instance = new SingletonType("singleton");
12
13 public SingletonType (String  name)
14 {
15 super(name);
16 }
17
18 public static final SingletonType getInstance () { return instance; }
19
20 public java.lang.Class getReflectClass()
21 {
22 return getImplementationType().getReflectClass();
23 }
24
25 public Type getImplementationType ()
26 {
27 return Type.pointer_type;
28 }
29
30 public int compare(Type other)
31 {
32 int otherRange = OccurrenceType.itemCountRange(other);
33 int otherMin = otherRange & 0xfff;
34 int otherMax = otherRange >> 12;
35 if (otherMax == 0 || otherMin > 1)
36 return -3;
37 if (otherMin == 1 && otherMax == 1)
38 return Type.pointer_type.compare(other);
39 int cmp = Type.pointer_type.compare(other);
40 if (cmp == 0 || cmp == -1)
41 return -1;
42 return -2;
43 }
44
45 public static Object coerceToSingleton (Object obj)
46 {
47 if (obj instanceof Values)
48 obj = ((Values) obj).canonicalize();
49 if (obj == null || obj instanceof Values)
50 throw new ClassCastException ("value if not a singleton");
51 return obj;
52 }
53
54 public Object coerceFromObject (Object obj)
55 {
56 return coerceToSingleton(obj);
57 }
58
59 public void emitCoerceFromObject (CodeAttr code)
60 {
61 code.emitInvokeStatic(ClassType.make("gnu.kawa.reflect.SingletonType")
62 .getDeclaredMethod("coerceToSingleton", 1));
63 }
64
65 public boolean isInstance (Object obj)
66 {
67 return obj != null && ! (obj instanceof Values);
68 }
69 }
70 |
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