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14 package jfun.yan;
15
16 import java.lang.reflect.InvocationHandler  ;
17 import java.lang.reflect.Method ;
18 import java.lang.reflect.Proxy ;
19
20 import jfun.util.Misc;
21 import jfun.yan.factory.Factory;
22
23
29 final class InstanceProxy
30 implements java.lang.reflect.InvocationHandler , Factory{
31 private final Class [] itfs;
32 private final ClassLoader loader;
33 private volatile Object v;
34 private final Factory factory;
35 private void set(Object obj){
36 v = obj;
37 }
38
41 private InstanceProxy(Factory factory, Class [] itfs, ClassLoader cl,
42 Object v) {
43 this.factory = factory;
44 this.itfs = itfs;
45 this.loader = cl;
46 this.v = v ;
47 }
48 public synchronized Object create(){
49 if(v==null){
50 v = factory.create();
51 }
52 return v;
53 }
54 public synchronized void clear(){
55 v = null;
56 }
57 public synchronized Object invoke(Object proxy, Method mtd, Object [] args)
58 throws Throwable {
59 try{
60 if(Object .class.equals(mtd.getDeclaringClass())){
61 return mtd.invoke(this, args);
62 }
63 else{
64 return mtd.invoke(create(), args);
65 }
66 }
67 catch(java.lang.reflect.InvocationTargetException e){
68 throw e.getTargetException();
69 }
70 }
71 static Object instance(ClassLoader cl, Class [] itfs, Factory factory){
72 final Class [] myitfs = copy(itfs);
73 return Proxy.newProxyInstance(cl,
74 myitfs, new InstanceProxy(factory, myitfs, cl, null));
75 }
76 static Class getProxyClass(ClassLoader cl, Class [] itfs){
77 return Proxy.getProxyClass(cl, itfs);
78 }
79 private Object getComparisonTarget(Object other){
80 if(other instanceof InstanceProxy){
81 final InstanceProxy p2 = (InstanceProxy)other;
82 return p2.create();
83 }
84 if(other instanceof Proxy ){
85 return getComparisonTarget(Proxy.getInvocationHandler(other));
86 }
87 return other;
88 }
89 public boolean equals(Object other) {
90 final Object v1 = create();
91 final Object v2 = getComparisonTarget(other);
92 return v1==null?(v2==null):v1.equals(v2);
93 }
94 public int hashCode() {
95 final Object v1 = create();
96 return v1==null?0:v1.hashCode();
97 }
98 public String toString() {
99 return ""+create();
100 }
101 static boolean setImplementation(Object proxy, Object obj){
102 if(!Proxy.isProxyClass(proxy.getClass())) return false;
103 final InvocationHandler ih = Proxy.getInvocationHandler(proxy);
104 if(ih instanceof InstanceProxy){
105 final InstanceProxy ip = (InstanceProxy)ih;
106 checkTypes(ip.itfs, obj);
107 ip.set(obj);
108 return true;
109 }
110 else return false;
111 }
112 static void clear(Object proxy){
113 if(!Proxy.isProxyClass(proxy.getClass())) return;
114 final InvocationHandler ih = Proxy.getInvocationHandler(proxy);
115 if(ih instanceof InstanceProxy){
116 final InstanceProxy ip = (InstanceProxy)ih;
117 ip.clear();
118 }
119 }
120 private static Class [] copy(Class [] types){
121 final Class [] ret = new Class [types.length];
122 for(int i=0; i<types.length; i++){
123 ret[i] = types[i];
124 }
125 return ret;
126 }
127 private static void checkTypes(Class [] types, Object obj){
128 for(int i=0; i<types.length; i++){
129 final Class type = types[i];
130 if(!type.isInstance(obj)){
131 throw new IllegalArgumentException ("object of type "
132 + Misc.getTypeName(Utils.getObjType(obj))
133 + " is not an instance of " + Misc.getTypeName(type));
134 }
135 }
136 }
137 }
138 |
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