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16 package net.sf.cglib.beans;
17
18 import java.beans.PropertyDescriptor  ;
19 import java.lang.reflect.Method ;
20 import net.sf.cglib.core.*;
21 import org.objectweb.asm.ClassVisitor;
22 import org.objectweb.asm.Type;
23
24
27 public class ImmutableBean
28 {
29 private static final Type ILLEGAL_STATE_EXCEPTION =
30 TypeUtils.parseType("IllegalStateException");
31 private static final Signature CSTRUCT_OBJECT =
32 TypeUtils.parseConstructor("Object");
33 private static final Class [] OBJECT_CLASSES = { Object .class };
34 private static final String FIELD_NAME = "CGLIB$RWBean";
35
36 private ImmutableBean() {
37 }
38
39 public static Object create(Object bean) {
40 Generator gen = new Generator();
41 gen.setBean(bean);
42 return gen.create();
43 }
44
45 public static class Generator extends AbstractClassGenerator {
46 private static final Source SOURCE = new Source(ImmutableBean.class.getName());
47 private Object bean;
48 private Class target;
49
50 public Generator() {
51 super(SOURCE);
52 }
53
54 public void setBean(Object bean) {
55 this.bean = bean;
56 target = bean.getClass();
57 }
58
59 protected ClassLoader getDefaultClassLoader() {
60 return target.getClassLoader();
61 }
62
63 public Object create() {
64 String name = target.getName();
65 setNamePrefix(name);
66 return super.create(name);
67 }
68
69 public void generateClass(ClassVisitor v) {
70 Type targetType = Type.getType(target);
71 ClassEmitter ce = new ClassEmitter(v);
72 ce.begin_class(Constants.V1_2,
73 Constants.ACC_PUBLIC,
74 getClassName(),
75 targetType,
76 null,
77 Constants.SOURCE_FILE);
78
79 ce.declare_field(Constants.ACC_FINAL | Constants.ACC_PRIVATE, FIELD_NAME, targetType, null);
80
81 CodeEmitter e = ce.begin_method(Constants.ACC_PUBLIC, CSTRUCT_OBJECT, null);
82 e.load_this();
83 e.super_invoke_constructor();
84 e.load_this();
85 e.load_arg(0);
86 e.checkcast(targetType);
87 e.putfield(FIELD_NAME);
88 e.return_value();
89 e.end_method();
90
91 PropertyDescriptor [] descriptors = ReflectUtils.getBeanProperties(target);
92 Method [] getters = ReflectUtils.getPropertyMethods(descriptors, true, false);
93 Method [] setters = ReflectUtils.getPropertyMethods(descriptors, false, true);
94
95 for (int i = 0; i < getters.length; i++) {
96 MethodInfo getter = ReflectUtils.getMethodInfo(getters[i]);
97 e = EmitUtils.begin_method(ce, getter, Constants.ACC_PUBLIC);
98 e.load_this();
99 e.getfield(FIELD_NAME);
100 e.invoke(getter);
101 e.return_value();
102 e.end_method();
103 }
104
105 for (int i = 0; i < setters.length; i++) {
106 MethodInfo setter = ReflectUtils.getMethodInfo(setters[i]);
107 e = EmitUtils.begin_method(ce, setter, Constants.ACC_PUBLIC);
108 e.throw_exception(ILLEGAL_STATE_EXCEPTION, "Bean is immutable");
109 e.end_method();
110 }
111
112 ce.end_class();
113 }
114
115 protected Object firstInstance(Class type) {
116 return ReflectUtils.newInstance(type, OBJECT_CLASSES, new Object []{ bean });
117 }
118
119 protected Object nextInstance(Object instance) {
121 return firstInstance(instance.getClass());
122 }
123 }
124 }
125 |
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