forked from jboss-javassist/javassist
-
Notifications
You must be signed in to change notification settings - Fork 0
/
ProxyFactory.java
1607 lines (1444 loc) · 60.6 KB
/
ProxyFactory.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.util.proxy;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.WeakHashMap;
import java.lang.invoke.MethodHandles.Lookup;
import javassist.CannotCompileException;
import javassist.bytecode.AccessFlag;
import javassist.bytecode.Bytecode;
import javassist.bytecode.ClassFile;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.ConstPool;
import javassist.bytecode.Descriptor;
import javassist.bytecode.DuplicateMemberException;
import javassist.bytecode.ExceptionsAttribute;
import javassist.bytecode.FieldInfo;
import javassist.bytecode.MethodInfo;
import javassist.bytecode.Opcode;
import javassist.bytecode.StackMapTable;
/*
* This class is implemented only with the lower-level API of Javassist.
* This design decision is for maximizing performance.
*/
/**
* Factory of dynamic proxy classes.
*
* <p>This factory generates a class that extends the given super class and implements
* the given interfaces. The calls of the methods inherited from the super class are
* forwarded and then <code>invoke()</code> is called on the method handler
* associated with instances of the generated class. The calls of the methods from
* the interfaces are also forwarded to the method handler.
*
* <p>For example, if the following code is executed,
*
* <pre>
* ProxyFactory f = new ProxyFactory();
* f.setSuperclass(Foo.class);
* f.setFilter(new MethodFilter() {
* public boolean isHandled(Method m) {
* // ignore finalize()
* return !m.getName().equals("finalize");
* }
* });
* Class c = f.createClass();
* MethodHandler mi = new MethodHandler() {
* public Object invoke(Object self, Method m, Method proceed,
* Object[] args) throws Throwable {
* System.out.println("Name: " + m.getName());
* return proceed.invoke(self, args); // execute the original method.
* }
* };
* Foo foo = (Foo)c.newInstance();
* ((Proxy)foo).setHandler(mi);
* </pre>
*
* <p>Here, <code>Method</code> is <code>java.lang.reflect.Method</code>.</p>
*
* <p>Then, the following method call will be forwarded to MethodHandler
* <code>mi</code> and prints a message before executing the originally called method
* <code>bar()</code> in <code>Foo</code>.
*
* <pre>
* foo.bar();
* </pre>
*
* <p>The last three lines of the code shown above can be replaced with a call to
* the helper method <code>create</code>, which generates a proxy class, instantiates
* it, and sets the method handler of the instance:
*
* <pre>
* :
* Foo foo = (Foo)f.create(new Class[0], new Object[0], mi);
* </pre>
*
* <p>To change the method handler during runtime,
* execute the following code:
*
* <pre>
* MethodHandler mi = ... ; // alternative handler
* ((Proxy)foo).setHandler(mi);
* </pre>
*
* <p> If setHandler is never called for a proxy instance then it will
* employ the default handler which proceeds by invoking the original method.
* The behaviour of the default handler is identical to the following
* handler:
*
* <pre>
* class EmptyHandler implements MethodHandler {
* public Object invoke(Object self, Method m,
* Method proceed, Object[] args) throws Exception {
* return proceed.invoke(self, args);
* }
* }
* </pre>
*
* <p>A proxy factory caches and reuses proxy classes by default. It is possible to reset
* this default globally by setting static field {@link ProxyFactory#useCache} to false.
* Caching may also be configured for a specific factory by calling instance method
* {@link ProxyFactory#setUseCache(boolean)}. It is strongly recommended that new clients
* of class ProxyFactory enable caching. Failure to do so may lead to exhaustion of
* the heap memory area used to store classes.
*
* <p>Caching is automatically disabled for any given proxy factory if deprecated instance
* method {@link ProxyFactory#setHandler(MethodHandler)} is called. This method was
* used to specify a default handler which newly created proxy classes should install
* when they create their instances. It is only retained to provide backward compatibility
* with previous releases of javassist. Unfortunately,this legacy behaviour makes caching
* and reuse of proxy classes impossible. The current programming model expects javassist
* clients to set the handler of a proxy instance explicitly by calling method
* {@link Proxy#setHandler(MethodHandler)} as shown in the sample code above. New
* clients are strongly recommended to use this model rather than calling
* {@link ProxyFactory#setHandler(MethodHandler)}.
*
* <p>A proxy object generated by <code>ProxyFactory</code> is serializable
* if its super class or any of its interfaces implement <code>java.io.Serializable</code>.
* However, a serialized proxy object may not be compatible with future releases.
* The serialization support should be used for short-term storage or RMI.
*
* <p>For compatibility with older releases serialization of proxy objects is implemented by
* adding a writeReplace method to the proxy class. This allows a proxy to be serialized
* to a conventional {@link java.io.ObjectOutputStream} and deserialized from a corresponding
* {@link java.io.ObjectInputStream}. However this method suffers from several problems, the most
* notable one being that it fails to serialize state inherited from the proxy's superclass.
* <p>
* An alternative method of serializing proxy objects is available which fixes these problems. It
* requires inhibiting generation of the writeReplace method and instead using instances of
* {@link javassist.util.proxy.ProxyObjectOutputStream} and {@link javassist.util.proxy.ProxyObjectInputStream}
* (which are subclasses of {@link java.io.ObjectOutputStream} and {@link java.io.ObjectInputStream})
* to serialize and deserialize, respectively, the proxy. These streams recognise javassist proxies and ensure
* that they are serialized and deserialized without the need for the proxy class to implement special methods
* such as writeReplace. Generation of the writeReplace method can be disabled globally by setting static field
* {@link ProxyFactory#useWriteReplace} to false. Alternatively, it may be
* configured per factory by calling instance method {@link ProxyFactory#setUseWriteReplace(boolean)}.
*
* @see MethodHandler
* @since 3.1
* @author Muga Nishizawa
* @author Shigeru Chiba
* @author Andrew Dinn
*/
public class ProxyFactory {
private Class<?> superClass;
private Class<?>[] interfaces;
private MethodFilter methodFilter;
private MethodHandler handler; // retained for legacy usage
private List<Map.Entry<String,Method>> signatureMethods;
private boolean hasGetHandler;
private byte[] signature;
private String classname;
private String basename;
private String superName;
private Class<?> thisClass;
/**
* per factory setting initialised from current setting for useCache but able to be reset before each create call
*/
private boolean factoryUseCache;
/**
* per factory setting initialised from current setting for useWriteReplace but able to be reset before each create call
*/
private boolean factoryWriteReplace;
/**
* <p>If true, only public/protected methods are forwarded to a proxy object.
* The class for that proxy object is loaded by the {@code defineClass} method
* in {@code java.lang.invoke.MethodHandles.Lookup}, which is available in
* Java 9 or later. This works even when {@code sun.misc.Unsafe} is not
* available for some reasons (it is already deprecated in Java 9).</p>
*
* <p>To load a class, Javassist first tries to use {@code sun.misc.Unsafe} and,
* if not available, it uses a {@code protected} method in {@code java.lang.ClassLoader}
* via {@code PrivilegedAction}. Since the latter approach is not available
* any longer by default in Java 9 or later, the JVM argument
* {@code --add-opens java.base/java.lang=ALL-UNNAMED} must be given to the JVM
* when it is used (because of lack of {@code sun.misc.Unsafe}).
* If this argument cannot be given to the JVM, {@code onlyPublicMethods} should
* be set to {@code true}. Javassist will try to load by using
* {@code java.lang.invoke.MethodHandles.Lookup}.</p>
*
* <p>The default value is {@code false}.</p>
*
* @see DefineClassHelper#toClass(String, Class, ClassLoader, ProtectionDomain, byte[])
* @since 3.22
*/
public static boolean onlyPublicMethods = false;
/**
* If the value of this variable is not null, the class file of
* the generated proxy class is written under the directory specified
* by this variable. For example, if the value is
* <code>"."</code>, then the class file is written under the current
* directory. This method is for debugging.
*
* <p>The default value is null.
*/
public String writeDirectory;
private static final Class<?> OBJECT_TYPE = Object.class;
private static final String HOLDER = "_methods_";
private static final String HOLDER_TYPE = "[Ljava/lang/reflect/Method;";
private static final String FILTER_SIGNATURE_FIELD = "_filter_signature";
private static final String FILTER_SIGNATURE_TYPE = "[B";
private static final String HANDLER = "handler";
private static final String NULL_INTERCEPTOR_HOLDER = "javassist.util.proxy.RuntimeSupport";
private static final String DEFAULT_INTERCEPTOR = "default_interceptor";
private static final String HANDLER_TYPE
= 'L' + MethodHandler.class.getName().replace('.', '/') + ';';
private static final String HANDLER_SETTER = "setHandler";
private static final String HANDLER_SETTER_TYPE = "(" + HANDLER_TYPE + ")V";
private static final String HANDLER_GETTER = "getHandler";
private static final String HANDLER_GETTER_TYPE = "()" + HANDLER_TYPE;
private static final String SERIAL_VERSION_UID_FIELD = "serialVersionUID";
private static final String SERIAL_VERSION_UID_TYPE = "J";
private static final long SERIAL_VERSION_UID_VALUE = -1L;
/**
* If true, a generated proxy class is cached and it will be reused
* when generating the proxy class with the same properties is requested.
* The default value is true.
*
* Note that this value merely specifies the initial setting employed by any newly created
* proxy factory. The factory setting may be overwritten by calling factory instance method
* {@link #setUseCache(boolean)}
*
* @since 3.4
*/
public static volatile boolean useCache = true;
/**
* If true, a generated proxy class will implement method writeReplace enabling
* serialization of its proxies to a conventional ObjectOutputStream. this (default)
* setting retains the old javassist behaviour which has the advantage that it
* retains compatibility with older releases and requires no extra work on the part
* of the client performing the serialization. However, it has the disadvantage that
* state inherited from the superclasses of the proxy is lost during serialization.
* if false then serialization/deserialization of the proxy instances will preserve
* all fields. However, serialization must be performed via a {@link ProxyObjectOutputStream}
* and deserialization must be via {@link ProxyObjectInputStream}. Any attempt to serialize
* proxies whose class was created with useWriteReplace set to false via a normal
* {@link java.io.ObjectOutputStream} will fail.
*
* Note that this value merely specifies the initial setting employed by any newly created
* proxy factory. The factory setting may be overwritten by calling factory instance method
* {@link #setUseWriteReplace(boolean)}
*
* @since 3.4
*/
public static volatile boolean useWriteReplace = true;
/*
* methods allowing individual factory settings for factoryUseCache and factoryWriteReplace to be reset
*/
/**
* test whether this factory uses the proxy cache
* @return true if this factory uses the proxy cache otherwise false
*/
public boolean isUseCache()
{
return factoryUseCache;
}
/**
* configure whether this factory should use the proxy cache
* @param useCache true if this factory should use the proxy cache and false if it should not use the cache
* @throws RuntimeException if a default interceptor has been set for the factory
*/
public void setUseCache(boolean useCache)
{
// we cannot allow caching to be used if the factory is configured to install a default interceptor
// field into generated classes
if (handler != null && useCache) {
throw new RuntimeException("caching cannot be enabled if the factory default interceptor has been set");
}
factoryUseCache = useCache;
}
/**
* test whether this factory installs a writeReplace method in created classes
* @return true if this factory installs a writeReplace method in created classes otherwise false
*/
public boolean isUseWriteReplace()
{
return factoryWriteReplace;
}
/**
* configure whether this factory should add a writeReplace method to created classes
* @param useWriteReplace true if this factory should add a writeReplace method to created classes and false if it
* should not add a writeReplace method
*/
public void setUseWriteReplace(boolean useWriteReplace)
{
factoryWriteReplace = useWriteReplace;
}
private static Map<ClassLoader,Map<String,ProxyDetails>> proxyCache =
new WeakHashMap<ClassLoader,Map<String,ProxyDetails>>();
/**
* determine if a class is a javassist proxy class
* @param cl
* @return true if the class is a javassist proxy class otherwise false
*/
public static boolean isProxyClass(Class<?> cl)
{
// all proxies implement Proxy or ProxyObject. nothing else should.
return (Proxy.class.isAssignableFrom(cl));
}
/**
* used to store details of a specific proxy class in the second tier of the proxy cache. this entry
* will be located in a hashmap keyed by the unique identifying name of the proxy class. the hashmap is
* located in a weak hashmap keyed by the classloader common to all proxy classes in the second tier map.
*/
static class ProxyDetails {
/**
* the unique signature of any method filter whose behaviour will be met by this class. each bit in
* the byte array is set if the filter redirects the corresponding super or interface method and clear
* if it does not redirect it.
*/
byte[] signature;
/**
* a hexadecimal string representation of the signature bit sequence. this string also forms part
* of the proxy class name.
*/
Reference<Class<?>> proxyClass;
/**
* a flag which is true this class employs writeReplace to perform serialization of its instances
* and false if serialization must employ of a ProxyObjectOutputStream and ProxyObjectInputStream
*/
boolean isUseWriteReplace;
ProxyDetails(byte[] signature, Class<?> proxyClass, boolean isUseWriteReplace)
{
this.signature = signature;
this.proxyClass = new WeakReference<Class<?>>(proxyClass);
this.isUseWriteReplace = isUseWriteReplace;
}
}
/**
* Constructs a factory of proxy class.
*/
public ProxyFactory() {
superClass = null;
interfaces = null;
methodFilter = null;
handler = null;
signature = null;
signatureMethods = null;
hasGetHandler = false;
thisClass = null;
writeDirectory = null;
factoryUseCache = useCache;
factoryWriteReplace = useWriteReplace;
}
/**
* Sets the super class of a proxy class.
*/
public void setSuperclass(Class<?> clazz) {
superClass = clazz;
// force recompute of signature
signature = null;
}
/**
* Obtains the super class set by <code>setSuperclass()</code>.
*
* @since 3.4
*/
public Class<?> getSuperclass() { return superClass; }
/**
* Sets the interfaces of a proxy class.
*/
public void setInterfaces(Class<?>[] ifs) {
interfaces = ifs;
// force recompute of signature
signature = null;
}
/**
* Obtains the interfaces set by <code>setInterfaces</code>.
*
* @since 3.4
*/
public Class<?>[] getInterfaces() { return interfaces; }
/**
* Sets a filter that selects the methods that will be controlled by a handler.
*/
public void setFilter(MethodFilter mf) {
methodFilter = mf;
// force recompute of signature
signature = null;
}
/**
* Generates a proxy class using the current filter.
* The module or package where a proxy class is created
* has to be opened to this package or the Javassist module.
*
* @see #createClass(Lookup)
*/
public Class<?> createClass() {
if (signature == null) {
computeSignature(methodFilter);
}
return createClass1(null);
}
/**
* Generates a proxy class using the supplied filter.
* The module or package where a proxy class is created
* has to be opened to this package or the Javassist module.
*/
public Class<?> createClass(MethodFilter filter) {
computeSignature(filter);
return createClass1(null);
}
/**
* Generates a proxy class with a specific signature.
* access is package local so ProxyObjectInputStream can use this
* @param signature
*/
Class<?> createClass(byte[] signature)
{
installSignature(signature);
return createClass1(null);
}
/**
* Generates a proxy class using the current filter.
* It loads a class file by the given
* {@code java.lang.invoke.MethodHandles.Lookup} object,
* which can be obtained by {@code MethodHandles.lookup()} called from
* somewhere in the package that the loaded class belongs to.
*
* @param lookup used for loading the proxy class.
* It needs an appropriate right to invoke {@code defineClass}
* for the proxy class.
* @since 3.24
*/
public Class<?> createClass(Lookup lookup) {
if (signature == null) {
computeSignature(methodFilter);
}
return createClass1(lookup);
}
/**
* Generates a proxy class using the supplied filter.
*
* @param lookup used for loading the proxy class.
* It needs an appropriate right to invoke {@code defineClass}
* for the proxy class.
* @param filter the filter.
* @see #createClass(Lookup)
* @since 3.24
*/
public Class<?> createClass(Lookup lookup, MethodFilter filter) {
computeSignature(filter);
return createClass1(lookup);
}
/**
* Generates a proxy class with a specific signature.
* access is package local so ProxyObjectInputStream can use this.
*
* @param lookup used for loading the proxy class.
* It needs an appropriate right to invoke {@code defineClass}
* for the proxy class.
* @param signature the signature.
*/
Class<?> createClass(Lookup lookup, byte[] signature)
{
installSignature(signature);
return createClass1(lookup);
}
private Class<?> createClass1(Lookup lookup) {
Class<?> result = thisClass;
if (result == null) {
ClassLoader cl = getClassLoader();
synchronized (proxyCache) {
if (factoryUseCache)
createClass2(cl, lookup);
else
createClass3(cl, lookup);
result = thisClass;
// don't retain any unwanted references
thisClass = null;
}
}
return result;
}
private static char[] hexDigits =
{ '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
public String getKey(Class<?> superClass, Class<?>[] interfaces, byte[] signature, boolean useWriteReplace)
{
StringBuffer sbuf = new StringBuffer();
if (superClass != null){
sbuf.append(superClass.getName());
}
sbuf.append(":");
for (int i = 0; i < interfaces.length; i++) {
sbuf.append(interfaces[i].getName());
sbuf.append(":");
}
for (int i = 0; i < signature.length; i++) {
byte b = signature[i];
int lo = b & 0xf;
int hi = (b >> 4) & 0xf;
sbuf.append(hexDigits[lo]);
sbuf.append(hexDigits[hi]);
}
if (useWriteReplace) {
sbuf.append(":w");
}
return sbuf.toString();
}
private void createClass2(ClassLoader cl, Lookup lookup) {
String key = getKey(superClass, interfaces, signature, factoryWriteReplace);
/*
* Excessive concurrency causes a large memory footprint and slows the
* execution speed down (with JDK 1.5). Thus, we use a jumbo lock for
* reducing concrrency.
*/
// synchronized (proxyCache) {
Map<String,ProxyDetails> cacheForTheLoader = proxyCache.get(cl);
ProxyDetails details;
if (cacheForTheLoader == null) {
cacheForTheLoader = new HashMap<String,ProxyDetails>();
proxyCache.put(cl, cacheForTheLoader);
}
details = cacheForTheLoader.get(key);
if (details != null) {
Reference<Class<?>> reference = details.proxyClass;
thisClass = reference.get();
if (thisClass != null) {
return;
}
}
createClass3(cl, lookup);
details = new ProxyDetails(signature, thisClass, factoryWriteReplace);
cacheForTheLoader.put(key, details);
// }
}
private void createClass3(ClassLoader cl, Lookup lookup) {
// we need a new class so we need a new class name
allocateClassName();
try {
ClassFile cf = make();
if (writeDirectory != null)
FactoryHelper.writeFile(cf, writeDirectory);
if (lookup == null)
thisClass = FactoryHelper.toClass(cf, getClassInTheSamePackage(), cl, getDomain());
else
thisClass = FactoryHelper.toClass(cf, lookup);
setField(FILTER_SIGNATURE_FIELD, signature);
// legacy behaviour : we only set the default interceptor static field if we are not using the cache
if (!factoryUseCache) {
setField(DEFAULT_INTERCEPTOR, handler);
}
}
catch (CannotCompileException e) {
throw new RuntimeException(e.getMessage(), e);
}
}
/**
* Obtains a class belonging to the same package that the created
* proxy class belongs to. It is used to obtain an appropriate
* {@code java.lang.invoke.MethodHandles.Lookup}.
*/
private Class<?> getClassInTheSamePackage() {
if (basename.startsWith(packageForJavaBase)) // maybe the super class is java.*
return this.getClass();
else if (superClass != null && superClass != OBJECT_TYPE)
return superClass;
else if (interfaces != null && interfaces.length > 0)
return interfaces[0];
else
return this.getClass(); // maybe wrong?
}
private void setField(String fieldName, Object value) {
if (thisClass != null && value != null)
try {
Field f = thisClass.getField(fieldName);
SecurityActions.setAccessible(f, true);
f.set(null, value);
SecurityActions.setAccessible(f, false);
}
catch (Exception e) {
throw new RuntimeException(e);
}
}
static byte[] getFilterSignature(Class<?> clazz) {
return (byte[])getField(clazz, FILTER_SIGNATURE_FIELD);
}
private static Object getField(Class<?> clazz, String fieldName) {
try {
Field f = clazz.getField(fieldName);
f.setAccessible(true);
Object value = f.get(null);
f.setAccessible(false);
return value;
}
catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* Obtains the method handler of the given proxy object.
*
* @param p a proxy object.
* @return the method handler.
* @since 3.16
*/
public static MethodHandler getHandler(Proxy p) {
try {
Field f = p.getClass().getDeclaredField(HANDLER);
f.setAccessible(true);
Object value = f.get(p);
f.setAccessible(false);
return (MethodHandler)value;
}
catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* A provider of class loaders.
*
* @see #classLoaderProvider
* @since 3.4
*/
public static interface ClassLoaderProvider {
/**
* Returns a class loader.
*
* @param pf a proxy factory that is going to obtain a class loader.
*/
public ClassLoader get(ProxyFactory pf);
}
/**
* A provider used by <code>createClass()</code> for obtaining
* a class loader.
* <code>get()</code> on this <code>ClassLoaderProvider</code> object
* is called to obtain a class loader.
*
* <p>The value of this field can be updated for changing the default
* implementation.
*
* <p>Example:
* <pre>
* ProxyFactory.classLoaderProvider = new ProxyFactory.ClassLoaderProvider() {
* public ClassLoader get(ProxyFactory pf) {
* return Thread.currentThread().getContextClassLoader();
* }
* };
* </pre>
*
* @since 3.4
*/
public static ClassLoaderProvider classLoaderProvider =
new ClassLoaderProvider() {
@Override
public ClassLoader get(ProxyFactory pf) {
return pf.getClassLoader0();
}
};
protected ClassLoader getClassLoader() {
return classLoaderProvider.get(this);
}
protected ClassLoader getClassLoader0() {
ClassLoader loader = null;
if (superClass != null && !superClass.getName().equals("java.lang.Object"))
loader = superClass.getClassLoader();
else if (interfaces != null && interfaces.length > 0)
loader = interfaces[0].getClassLoader();
if (loader == null) {
loader = getClass().getClassLoader();
// In case javassist is in the endorsed dir
if (loader == null) {
loader = Thread.currentThread().getContextClassLoader();
if (loader == null)
loader = ClassLoader.getSystemClassLoader();
}
}
return loader;
}
protected ProtectionDomain getDomain() {
Class<?> clazz;
if (superClass != null && !superClass.getName().equals("java.lang.Object"))
clazz = superClass;
else if (interfaces != null && interfaces.length > 0)
clazz = interfaces[0];
else
clazz = this.getClass();
return clazz.getProtectionDomain();
}
/**
* Creates a proxy class and returns an instance of that class.
*
* @param paramTypes parameter types for a constructor.
* @param args arguments passed to a constructor.
* @param mh the method handler for the proxy class.
* @since 3.4
*/
public Object create(Class<?>[] paramTypes, Object[] args, MethodHandler mh)
throws NoSuchMethodException, IllegalArgumentException,
InstantiationException, IllegalAccessException, InvocationTargetException
{
Object obj = create(paramTypes, args);
((Proxy)obj).setHandler(mh);
return obj;
}
/**
* Creates a proxy class and returns an instance of that class.
*
* @param paramTypes parameter types for a constructor.
* @param args arguments passed to a constructor.
*/
public Object create(Class<?>[] paramTypes, Object[] args)
throws NoSuchMethodException, IllegalArgumentException,
InstantiationException, IllegalAccessException, InvocationTargetException
{
Class<?> c = createClass();
Constructor<?> cons = c.getConstructor(paramTypes);
return cons.newInstance(args);
}
/**
* Sets the default invocation handler. This invocation handler is shared
* among all the instances of a proxy class unless another is explicitly
* specified.
* @deprecated since 3.12
* use of this method is incompatible with proxy class caching.
* instead clients should call method {@link Proxy#setHandler(MethodHandler)} to set the handler
* for each newly created proxy instance.
* calling this method will automatically disable caching of classes created by the proxy factory.
*/
@Deprecated
public void setHandler(MethodHandler mi) {
// if we were using the cache and the handler is non-null then we must stop caching
if (factoryUseCache && mi != null) {
factoryUseCache = false;
// clear any currently held class so we don't try to reuse it or set its handler field
thisClass = null;
}
handler = mi;
// this retains the behaviour of the old code which resets any class we were holding on to
// this is probably not what is wanted
setField(DEFAULT_INTERCEPTOR, handler);
}
/**
* A unique class name generator.
*/
public static interface UniqueName {
/**
* Returns a unique class name.
*
* @param classname the super class name of the proxy class.
*/
String get(String classname);
}
/**
* A unique class name generator.
* Replacing this generator changes the algorithm to generate a
* unique name. The <code>get</code> method does not have to be
* a <code>synchronized</code> method since the access to this field
* is mutually exclusive and thus thread safe.
*/
public static UniqueName nameGenerator = new UniqueName() {
private final String sep = "_$$_jvst" + Integer.toHexString(this.hashCode() & 0xfff) + "_";
private int counter = 0;
@Override
public String get(String classname) {
return classname + sep + Integer.toHexString(counter++);
}
};
private static String makeProxyName(String classname) {
synchronized (nameGenerator) {
return nameGenerator.get(classname);
}
}
private ClassFile make() throws CannotCompileException {
ClassFile cf = new ClassFile(false, classname, superName);
cf.setAccessFlags(AccessFlag.PUBLIC);
setInterfaces(cf, interfaces, hasGetHandler ? Proxy.class : ProxyObject.class);
ConstPool pool = cf.getConstPool();
// legacy: we only add the static field for the default interceptor if caching is disabled
if (!factoryUseCache) {
FieldInfo finfo = new FieldInfo(pool, DEFAULT_INTERCEPTOR, HANDLER_TYPE);
finfo.setAccessFlags(AccessFlag.PUBLIC | AccessFlag.STATIC);
cf.addField(finfo);
}
// handler is per instance
FieldInfo finfo2 = new FieldInfo(pool, HANDLER, HANDLER_TYPE);
finfo2.setAccessFlags(AccessFlag.PRIVATE);
cf.addField(finfo2);
// filter signature is per class
FieldInfo finfo3 = new FieldInfo(pool, FILTER_SIGNATURE_FIELD, FILTER_SIGNATURE_TYPE);
finfo3.setAccessFlags(AccessFlag.PUBLIC | AccessFlag.STATIC);
cf.addField(finfo3);
// the proxy class serial uid must always be a fixed value
FieldInfo finfo4 = new FieldInfo(pool, SERIAL_VERSION_UID_FIELD, SERIAL_VERSION_UID_TYPE);
finfo4.setAccessFlags(AccessFlag.PUBLIC | AccessFlag.STATIC| AccessFlag.FINAL);
cf.addField(finfo4);
// HashMap allMethods = getMethods(superClass, interfaces);
// int size = allMethods.size();
makeConstructors(classname, cf, pool, classname);
List<Find2MethodsArgs> forwarders = new ArrayList<Find2MethodsArgs>();
int s = overrideMethods(cf, pool, classname, forwarders);
addClassInitializer(cf, pool, classname, s, forwarders);
addSetter(classname, cf, pool);
if (!hasGetHandler)
addGetter(classname, cf, pool);
if (factoryWriteReplace) {
try {
cf.addMethod(makeWriteReplace(pool));
}
catch (DuplicateMemberException e) {
// writeReplace() is already declared in the super class/interfaces.
}
}
thisClass = null;
return cf;
}
private void checkClassAndSuperName() {
if (interfaces == null)
interfaces = new Class[0];
if (superClass == null) {
superClass = OBJECT_TYPE;
superName = superClass.getName();
basename = interfaces.length == 0 ? superName
: interfaces[0].getName();
} else {
superName = superClass.getName();
basename = superName;
}
if (Modifier.isFinal(superClass.getModifiers()))
throw new RuntimeException(superName + " is final");
// Since java.base module is not opened, its proxy class should be
// in a different (open) module. Otherwise, it could not be created
// by reflection.
if (basename.startsWith("java.") || basename.startsWith("jdk.") || onlyPublicMethods)
basename = packageForJavaBase + basename.replace('.', '_');
}
private static final String packageForJavaBase = "javassist.util.proxy.";
private void allocateClassName() {
classname = makeProxyName(basename);
}
private static Comparator<Map.Entry<String,Method>> sorter =
new Comparator<Map.Entry<String,Method>>() {
@Override
public int compare(Map.Entry<String,Method> e1, Map.Entry<String,Method> e2) {
return e1.getKey().compareTo(e2.getKey());
}
};
private void makeSortedMethodList() {
checkClassAndSuperName();
hasGetHandler = false; // getMethods() may set this to true.
Map<String,Method> allMethods = getMethods(superClass, interfaces);
signatureMethods = new ArrayList<Map.Entry<String,Method>>(allMethods.entrySet());
Collections.sort(signatureMethods, sorter);
}
private void computeSignature(MethodFilter filter) // throws CannotCompileException
{
makeSortedMethodList();
int l = signatureMethods.size();
int maxBytes = ((l + 7) >> 3);
signature = new byte[maxBytes];
for (int idx = 0; idx < l; idx++)
{
Method m = signatureMethods.get(idx).getValue();
int mod = m.getModifiers();
if (!Modifier.isFinal(mod) && !Modifier.isStatic(mod)
&& isVisible(mod, basename, m) && (filter == null || filter.isHandled(m))) {
setBit(signature, idx);
}
}
}
private void installSignature(byte[] signature) // throws CannotCompileException
{
makeSortedMethodList();
int l = signatureMethods.size();
int maxBytes = ((l + 7) >> 3);
if (signature.length != maxBytes) {
throw new RuntimeException("invalid filter signature length for deserialized proxy class");
}
this.signature = signature;
}
private boolean testBit(byte[] signature, int idx) {
int byteIdx = idx >> 3;
if (byteIdx > signature.length)
return false;
int bitIdx = idx & 0x7;
int mask = 0x1 << bitIdx;
int sigByte = signature[byteIdx];
return ((sigByte & mask) != 0);
}
private void setBit(byte[] signature, int idx) {