1 /*
2 * Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.reflect;
27
28 import jdk.internal.HotSpotIntrinsicCandidate;
29 import jdk.internal.misc.SharedSecrets;
30 import jdk.internal.reflect.CallerSensitive;
31 import jdk.internal.reflect.MethodAccessor;
32 import jdk.internal.reflect.Reflection;
33 import jdk.internal.vm.annotation.ForceInline;
34 import sun.reflect.annotation.ExceptionProxy;
35 import sun.reflect.annotation.TypeNotPresentExceptionProxy;
36 import sun.reflect.generics.repository.MethodRepository;
37 import sun.reflect.generics.factory.CoreReflectionFactory;
38 import sun.reflect.generics.factory.GenericsFactory;
39 import sun.reflect.generics.scope.MethodScope;
40 import sun.reflect.annotation.AnnotationType;
41 import sun.reflect.annotation.AnnotationParser;
42 import java.lang.annotation.Annotation;
43 import java.lang.annotation.AnnotationFormatError;
44 import java.nio.ByteBuffer;
45
46 /**
47 * A {@code Method} provides information about, and access to, a single method
48 * on a class or interface. The reflected method may be a class method
49 * or an instance method (including an abstract method).
50 *
51 * <p>A {@code Method} permits widening conversions to occur when matching the
52 * actual parameters to invoke with the underlying method's formal
53 * parameters, but it throws an {@code IllegalArgumentException} if a
54 * narrowing conversion would occur.
55 *
56 * @see Member
57 * @see java.lang.Class
58 * @see java.lang.Class#getMethods()
59 * @see java.lang.Class#getMethod(String, Class[])
60 * @see java.lang.Class#getDeclaredMethods()
61 * @see java.lang.Class#getDeclaredMethod(String, Class[])
62 *
63 * @author Kenneth Russell
64 * @author Nakul Saraiya
65 */
66 public final class Method extends Executable {
67 private Class<?> clazz;
68 private int slot;
69 // This is guaranteed to be interned by the VM in the 1.4
70 // reflection implementation
71 private String name;
72 private Class<?> returnType;
73 private Class<?>[] parameterTypes;
74 private Class<?>[] exceptionTypes;
75 private int modifiers;
76 // Generics and annotations support
77 private transient String signature;
78 // generic info repository; lazily initialized
79 private transient MethodRepository genericInfo;
80 private byte[] annotations;
81 private byte[] parameterAnnotations;
82 private byte[] annotationDefault;
83 private volatile MethodAccessor methodAccessor;
84 // For sharing of MethodAccessors. This branching structure is
85 // currently only two levels deep (i.e., one root Method and
86 // potentially many Method objects pointing to it.)
87 //
88 // If this branching structure would ever contain cycles, deadlocks can
89 // occur in annotation code.
90 private Method root;
91
92 // Generics infrastructure
93 private String getGenericSignature() {return signature;}
94
95 // Accessor for factory
96 private GenericsFactory getFactory() {
97 // create scope and factory
98 return CoreReflectionFactory.make(this, MethodScope.make(this));
99 }
100
101 // Accessor for generic info repository
102 @Override
103 MethodRepository getGenericInfo() {
104 // lazily initialize repository if necessary
105 if (genericInfo == null) {
106 // create and cache generic info repository
107 genericInfo = MethodRepository.make(getGenericSignature(),
108 getFactory());
109 }
110 return genericInfo; //return cached repository
111 }
112
113 /**
114 * Package-private constructor used by ReflectAccess to enable
115 * instantiation of these objects in Java code from the java.lang
116 * package via sun.reflect.LangReflectAccess.
117 */
118 Method(Class<?> declaringClass,
119 String name,
120 Class<?>[] parameterTypes,
121 Class<?> returnType,
122 Class<?>[] checkedExceptions,
123 int modifiers,
124 int slot,
125 String signature,
126 byte[] annotations,
127 byte[] parameterAnnotations,
128 byte[] annotationDefault) {
129 this.clazz = declaringClass;
130 this.name = name;
131 this.parameterTypes = parameterTypes;
132 this.returnType = returnType;
133 this.exceptionTypes = checkedExceptions;
134 this.modifiers = modifiers;
135 this.slot = slot;
136 this.signature = signature;
137 this.annotations = annotations;
138 this.parameterAnnotations = parameterAnnotations;
139 this.annotationDefault = annotationDefault;
140 }
141
142 /**
143 * Package-private routine (exposed to java.lang.Class via
144 * ReflectAccess) which returns a copy of this Method. The copy's
145 * "root" field points to this Method.
146 */
147 Method copy() {
148 // This routine enables sharing of MethodAccessor objects
149 // among Method objects which refer to the same underlying
150 // method in the VM. (All of this contortion is only necessary
151 // because of the "accessibility" bit in AccessibleObject,
152 // which implicitly requires that new java.lang.reflect
153 // objects be fabricated for each reflective call on Class
154 // objects.)
155 if (this.root != null)
156 throw new IllegalArgumentException("Can not copy a non-root Method");
157
158 Method res = new Method(clazz, name, parameterTypes, returnType,
159 exceptionTypes, modifiers, slot, signature,
160 annotations, parameterAnnotations, annotationDefault);
161 res.root = this;
162 // Might as well eagerly propagate this if already present
163 res.methodAccessor = methodAccessor;
164 return res;
165 }
166
167 /**
168 * Make a copy of a leaf method.
169 */
170 Method leafCopy() {
171 if (this.root == null)
172 throw new IllegalArgumentException("Can only leafCopy a non-root Method");
173
174 Method res = new Method(clazz, name, parameterTypes, returnType,
175 exceptionTypes, modifiers, slot, signature,
176 annotations, parameterAnnotations, annotationDefault);
177 res.root = root;
178 res.methodAccessor = methodAccessor;
179 return res;
180 }
181
182 @Override
183 @CallerSensitive
184 public void setAccessible(boolean flag) {
185 AccessibleObject.checkPermission();
186 if (flag) checkCanSetAccessible(Reflection.getCallerClass());
187 setAccessible0(flag);
188 }
189
190 @Override
191 void checkCanSetAccessible(Class<?> caller) {
192 checkCanSetAccessible(caller, clazz);
193 }
194
195 /**
196 * Used by Excecutable for annotation sharing.
197 */
198 @Override
199 Executable getRoot() {
200 return root;
201 }
202
203 @Override
204 boolean hasGenericInformation() {
205 return (getGenericSignature() != null);
206 }
207
208 @Override
209 byte[] getAnnotationBytes() {
210 return annotations;
211 }
212
213 /**
214 * {@inheritDoc}
215 */
216 @Override
217 public Class<?> getDeclaringClass() {
218 return clazz;
219 }
220
221 /**
222 * Returns the name of the method represented by this {@code Method}
223 * object, as a {@code String}.
224 */
225 @Override
226 public String getName() {
227 return name;
228 }
229
230 /**
231 * {@inheritDoc}
232 */
233 @Override
234 public int getModifiers() {
235 return modifiers;
236 }
237
238 /**
239 * {@inheritDoc}
240 * @throws GenericSignatureFormatError {@inheritDoc}
241 * @since 1.5
242 */
243 @Override
244 @SuppressWarnings({"rawtypes", "unchecked"})
245 public TypeVariable<Method>[] getTypeParameters() {
246 if (getGenericSignature() != null)
247 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters();
248 else
249 return (TypeVariable<Method>[])new TypeVariable[0];
250 }
251
252 /**
253 * Returns a {@code Class} object that represents the formal return type
254 * of the method represented by this {@code Method} object.
255 *
256 * @return the return type for the method this object represents
257 */
258 public Class<?> getReturnType() {
259 return returnType;
260 }
261
262 /**
263 * Returns a {@code Type} object that represents the formal return
264 * type of the method represented by this {@code Method} object.
265 *
266 * <p>If the return type is a parameterized type,
267 * the {@code Type} object returned must accurately reflect
268 * the actual type parameters used in the source code.
269 *
270 * <p>If the return type is a type variable or a parameterized type, it
271 * is created. Otherwise, it is resolved.
272 *
273 * @return a {@code Type} object that represents the formal return
274 * type of the underlying method
275 * @throws GenericSignatureFormatError
276 * if the generic method signature does not conform to the format
277 * specified in
278 * <cite>The Java™ Virtual Machine Specification</cite>
279 * @throws TypeNotPresentException if the underlying method's
280 * return type refers to a non-existent type declaration
281 * @throws MalformedParameterizedTypeException if the
282 * underlying method's return typed refers to a parameterized
283 * type that cannot be instantiated for any reason
284 * @since 1.5
285 */
286 public Type getGenericReturnType() {
287 if (getGenericSignature() != null) {
288 return getGenericInfo().getReturnType();
289 } else { return getReturnType();}
290 }
291
292 @Override
293 Class<?>[] getSharedParameterTypes() {
294 return parameterTypes;
295 }
296
297 /**
298 * {@inheritDoc}
299 */
300 @Override
301 public Class<?>[] getParameterTypes() {
302 return parameterTypes.clone();
303 }
304
305 /**
306 * {@inheritDoc}
307 * @since 1.8
308 */
309 public int getParameterCount() { return parameterTypes.length; }
310
311
312 /**
313 * {@inheritDoc}
314 * @throws GenericSignatureFormatError {@inheritDoc}
315 * @throws TypeNotPresentException {@inheritDoc}
316 * @throws MalformedParameterizedTypeException {@inheritDoc}
317 * @since 1.5
318 */
319 @Override
320 public Type[] getGenericParameterTypes() {
321 return super.getGenericParameterTypes();
322 }
323
324 /**
325 * {@inheritDoc}
326 */
327 @Override
328 public Class<?>[] getExceptionTypes() {
329 return exceptionTypes.clone();
330 }
331
332 /**
333 * {@inheritDoc}
334 * @throws GenericSignatureFormatError {@inheritDoc}
335 * @throws TypeNotPresentException {@inheritDoc}
336 * @throws MalformedParameterizedTypeException {@inheritDoc}
337 * @since 1.5
338 */
339 @Override
340 public Type[] getGenericExceptionTypes() {
341 return super.getGenericExceptionTypes();
342 }
343
344 /**
345 * Compares this {@code Method} against the specified object. Returns
346 * true if the objects are the same. Two {@code Methods} are the same if
347 * they were declared by the same class and have the same name
348 * and formal parameter types and return type.
349 */
350 public boolean equals(Object obj) {
351 if (obj != null && obj instanceof Method) {
352 Method other = (Method)obj;
353 if ((getDeclaringClass() == other.getDeclaringClass())
354 && (getName() == other.getName())) {
355 if (!returnType.equals(other.getReturnType()))
356 return false;
357 return equalParamTypes(parameterTypes, other.parameterTypes);
358 }
359 }
360 return false;
361 }
362
363 /**
364 * Returns a hashcode for this {@code Method}. The hashcode is computed
365 * as the exclusive-or of the hashcodes for the underlying
366 * method's declaring class name and the method's name.
367 */
368 public int hashCode() {
369 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
370 }
371
372 /**
373 * Returns a string describing this {@code Method}. The string is
374 * formatted as the method access modifiers, if any, followed by
375 * the method return type, followed by a space, followed by the
376 * class declaring the method, followed by a period, followed by
377 * the method name, followed by a parenthesized, comma-separated
378 * list of the method's formal parameter types. If the method
379 * throws checked exceptions, the parameter list is followed by a
380 * space, followed by the word throws followed by a
381 * comma-separated list of the thrown exception types.
382 * For example:
383 * <pre>
384 * public boolean java.lang.Object.equals(java.lang.Object)
385 * </pre>
386 *
387 * <p>The access modifiers are placed in canonical order as
388 * specified by "The Java Language Specification". This is
389 * {@code public}, {@code protected} or {@code private} first,
390 * and then other modifiers in the following order:
391 * {@code abstract}, {@code default}, {@code static}, {@code final},
392 * {@code synchronized}, {@code native}, {@code strictfp}.
393 *
394 * @return a string describing this {@code Method}
395 *
396 * @jls 8.4.3 Method Modifiers
397 * @jls 9.4 Method Declarations
398 * @jls 9.6.1 Annotation Type Elements
399 */
400 public String toString() {
401 return sharedToString(Modifier.methodModifiers(),
402 isDefault(),
403 parameterTypes,
404 exceptionTypes);
405 }
406
407 @Override
408 void specificToStringHeader(StringBuilder sb) {
409 sb.append(getReturnType().getTypeName()).append(' ');
410 sb.append(getDeclaringClass().getTypeName()).append('.');
411 sb.append(getName());
412 }
413
414 /**
415 * Returns a string describing this {@code Method}, including
416 * type parameters. The string is formatted as the method access
417 * modifiers, if any, followed by an angle-bracketed
418 * comma-separated list of the method's type parameters, if any,
419 * followed by the method's generic return type, followed by a
420 * space, followed by the class declaring the method, followed by
421 * a period, followed by the method name, followed by a
422 * parenthesized, comma-separated list of the method's generic
423 * formal parameter types.
424 *
425 * If this method was declared to take a variable number of
426 * arguments, instead of denoting the last parameter as
427 * "<code><i>Type</i>[]</code>", it is denoted as
428 * "<code><i>Type</i>...</code>".
429 *
430 * A space is used to separate access modifiers from one another
431 * and from the type parameters or return type. If there are no
432 * type parameters, the type parameter list is elided; if the type
433 * parameter list is present, a space separates the list from the
434 * class name. If the method is declared to throw exceptions, the
435 * parameter list is followed by a space, followed by the word
436 * throws followed by a comma-separated list of the generic thrown
437 * exception types.
438 *
439 * <p>The access modifiers are placed in canonical order as
440 * specified by "The Java Language Specification". This is
441 * {@code public}, {@code protected} or {@code private} first,
442 * and then other modifiers in the following order:
443 * {@code abstract}, {@code default}, {@code static}, {@code final},
444 * {@code synchronized}, {@code native}, {@code strictfp}.
445 *
446 * @return a string describing this {@code Method},
447 * include type parameters
448 *
449 * @since 1.5
450 *
451 * @jls 8.4.3 Method Modifiers
452 * @jls 9.4 Method Declarations
453 * @jls 9.6.1 Annotation Type Elements
454 */
455 @Override
456 public String toGenericString() {
457 return sharedToGenericString(Modifier.methodModifiers(), isDefault());
458 }
459
460 @Override
461 void specificToGenericStringHeader(StringBuilder sb) {
462 Type genRetType = getGenericReturnType();
463 sb.append(genRetType.getTypeName()).append(' ');
464 sb.append(getDeclaringClass().getTypeName()).append('.');
465 sb.append(getName());
466 }
467
468 /**
469 * Invokes the underlying method represented by this {@code Method}
470 * object, on the specified object with the specified parameters.
471 * Individual parameters are automatically unwrapped to match
472 * primitive formal parameters, and both primitive and reference
473 * parameters are subject to method invocation conversions as
474 * necessary.
475 *
476 * <p>If the underlying method is static, then the specified {@code obj}
477 * argument is ignored. It may be null.
478 *
479 * <p>If the number of formal parameters required by the underlying method is
480 * 0, the supplied {@code args} array may be of length 0 or null.
481 *
482 * <p>If the underlying method is an instance method, it is invoked
483 * using dynamic method lookup as documented in The Java Language
484 * Specification, Second Edition, section 15.12.4.4; in particular,
485 * overriding based on the runtime type of the target object will occur.
486 *
487 * <p>If the underlying method is static, the class that declared
488 * the method is initialized if it has not already been initialized.
489 *
490 * <p>If the method completes normally, the value it returns is
491 * returned to the caller of invoke; if the value has a primitive
492 * type, it is first appropriately wrapped in an object. However,
493 * if the value has the type of an array of a primitive type, the
494 * elements of the array are <i>not</i> wrapped in objects; in
495 * other words, an array of primitive type is returned. If the
496 * underlying method return type is void, the invocation returns
497 * null.
498 *
499 * @param obj the object the underlying method is invoked from
500 * @param args the arguments used for the method call
501 * @return the result of dispatching the method represented by
502 * this object on {@code obj} with parameters
503 * {@code args}
504 *
505 * @exception IllegalAccessException if this {@code Method} object
506 * is enforcing Java language access control and the underlying
507 * method is inaccessible.
508 * @exception IllegalArgumentException if the method is an
509 * instance method and the specified object argument
510 * is not an instance of the class or interface
511 * declaring the underlying method (or of a subclass
512 * or implementor thereof); if the number of actual
513 * and formal parameters differ; if an unwrapping
514 * conversion for primitive arguments fails; or if,
515 * after possible unwrapping, a parameter value
516 * cannot be converted to the corresponding formal
517 * parameter type by a method invocation conversion.
518 * @exception InvocationTargetException if the underlying method
519 * throws an exception.
520 * @exception NullPointerException if the specified object is null
521 * and the method is an instance method.
522 * @exception ExceptionInInitializerError if the initialization
523 * provoked by this method fails.
524 */
525 @CallerSensitive
526 @ForceInline // to ensure Reflection.getCallerClass optimization
527 @HotSpotIntrinsicCandidate
528 public Object invoke(Object obj, Object... args)
529 throws IllegalAccessException, IllegalArgumentException,
530 InvocationTargetException
531 {
532 if (!override) {
533 Class<?> caller = Reflection.getCallerClass();
534 checkAccess(caller, clazz, obj, modifiers);
535 }
536 MethodAccessor ma = methodAccessor; // read volatile
537 if (ma == null) {
538 ma = acquireMethodAccessor();
539 }
540 return ma.invoke(obj, args);
541 }
542
543 /**
544 * Returns {@code true} if this method is a bridge
545 * method; returns {@code false} otherwise.
546 *
547 * @return true if and only if this method is a bridge
548 * method as defined by the Java Language Specification.
549 * @since 1.5
550 */
551 public boolean isBridge() {
552 return (getModifiers() & Modifier.BRIDGE) != 0;
553 }
554
555 /**
556 * {@inheritDoc}
557 * @since 1.5
558 */
559 @Override
560 public boolean isVarArgs() {
561 return super.isVarArgs();
562 }
563
564 /**
565 * {@inheritDoc}
566 * @jls 13.1 The Form of a Binary
567 * @since 1.5
568 */
569 @Override
570 public boolean isSynthetic() {
571 return super.isSynthetic();
572 }
573
574 /**
575 * Returns {@code true} if this method is a default
576 * method; returns {@code false} otherwise.
577 *
578 * A default method is a public non-abstract instance method, that
579 * is, a non-static method with a body, declared in an interface
580 * type.
581 *
582 * @return true if and only if this method is a default
583 * method as defined by the Java Language Specification.
584 * @since 1.8
585 */
586 public boolean isDefault() {
587 // Default methods are public non-abstract instance methods
588 // declared in an interface.
589 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) ==
590 Modifier.PUBLIC) && getDeclaringClass().isInterface();
591 }
592
593 // NOTE that there is no synchronization used here. It is correct
594 // (though not efficient) to generate more than one MethodAccessor
595 // for a given Method. However, avoiding synchronization will
596 // probably make the implementation more scalable.
597 private MethodAccessor acquireMethodAccessor() {
598 // First check to see if one has been created yet, and take it
599 // if so
600 MethodAccessor tmp = null;
601 if (root != null) tmp = root.getMethodAccessor();
602 if (tmp != null) {
603 methodAccessor = tmp;
604 } else {
605 // Otherwise fabricate one and propagate it up to the root
606 tmp = reflectionFactory.newMethodAccessor(this);
607 setMethodAccessor(tmp);
608 }
609
610 return tmp;
611 }
612
613 // Returns MethodAccessor for this Method object, not looking up
614 // the chain to the root
615 MethodAccessor getMethodAccessor() {
616 return methodAccessor;
617 }
618
619 // Sets the MethodAccessor for this Method object and
620 // (recursively) its root
621 void setMethodAccessor(MethodAccessor accessor) {
622 methodAccessor = accessor;
623 // Propagate up
624 if (root != null) {
625 root.setMethodAccessor(accessor);
626 }
627 }
628
629 /**
630 * Returns the default value for the annotation member represented by
631 * this {@code Method} instance. If the member is of a primitive type,
632 * an instance of the corresponding wrapper type is returned. Returns
633 * null if no default is associated with the member, or if the method
634 * instance does not represent a declared member of an annotation type.
635 *
636 * @return the default value for the annotation member represented
637 * by this {@code Method} instance.
638 * @throws TypeNotPresentException if the annotation is of type
639 * {@link Class} and no definition can be found for the
640 * default class value.
641 * @since 1.5
642 */
643 public Object getDefaultValue() {
644 if (annotationDefault == null)
645 return null;
646 Class<?> memberType = AnnotationType.invocationHandlerReturnType(
647 getReturnType());
648 Object result = AnnotationParser.parseMemberValue(
649 memberType, ByteBuffer.wrap(annotationDefault),
650 SharedSecrets.getJavaLangAccess().
651 getConstantPool(getDeclaringClass()),
652 getDeclaringClass());
653 if (result instanceof ExceptionProxy) {
654 if (result instanceof TypeNotPresentExceptionProxy) {
655 TypeNotPresentExceptionProxy proxy = (TypeNotPresentExceptionProxy)result;
656 throw new TypeNotPresentException(proxy.typeName(), proxy.getCause());
657 }
658 throw new AnnotationFormatError("Invalid default: " + this);
659 }
660 return result;
661 }
662
663 /**
664 * {@inheritDoc}
665 * @throws NullPointerException {@inheritDoc}
666 * @since 1.5
667 */
668 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
669 return super.getAnnotation(annotationClass);
670 }
671
672 /**
673 * {@inheritDoc}
674 * @since 1.5
675 */
676 public Annotation[] getDeclaredAnnotations() {
677 return super.getDeclaredAnnotations();
678 }
679
680 /**
681 * {@inheritDoc}
682 * @since 1.5
683 */
684 @Override
685 public Annotation[][] getParameterAnnotations() {
686 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
687 }
688
689 /**
690 * {@inheritDoc}
691 * @since 1.8
692 */
693 @Override
694 public AnnotatedType getAnnotatedReturnType() {
695 return getAnnotatedReturnType0(getGenericReturnType());
696 }
697
698 @Override
699 void handleParameterNumberMismatch(int resultLength, int numParameters) {
700 throw new AnnotationFormatError("Parameter annotations don't match number of parameters");
701 }
702 }