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 /**
183 * @throws InaccessibleObjectException {@inheritDoc}
184 * @throws SecurityException {@inheritDoc}
185 */
186 @Override
187 @CallerSensitive
188 public void setAccessible(boolean flag) {
189 AccessibleObject.checkPermission();
190 if (flag) checkCanSetAccessible(Reflection.getCallerClass());
191 setAccessible0(flag);
192 }
193
194 @Override
195 void checkCanSetAccessible(Class<?> caller) {
196 checkCanSetAccessible(caller, clazz);
197 }
198
199 /**
200 * Used by Excecutable for annotation sharing.
201 */
202 @Override
203 Executable getRoot() {
204 return root;
205 }
206
207 @Override
208 boolean hasGenericInformation() {
209 return (getGenericSignature() != null);
210 }
211
212 @Override
213 byte[] getAnnotationBytes() {
214 return annotations;
215 }
216
217 /**
218 * Returns the {@code Class} object representing the class or interface
219 * that declares the method represented by this object.
220 */
221 @Override
222 public Class<?> getDeclaringClass() {
223 return clazz;
224 }
225
226 /**
227 * Returns the name of the method represented by this {@code Method}
228 * object, as a {@code String}.
229 */
230 @Override
231 public String getName() {
232 return name;
233 }
234
235 /**
236 * {@inheritDoc}
237 */
238 @Override
239 public int getModifiers() {
240 return modifiers;
241 }
242
243 /**
244 * {@inheritDoc}
245 * @throws GenericSignatureFormatError {@inheritDoc}
246 * @since 1.5
247 */
248 @Override
249 @SuppressWarnings({"rawtypes", "unchecked"})
250 public TypeVariable<Method>[] getTypeParameters() {
251 if (getGenericSignature() != null)
252 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters();
253 else
254 return (TypeVariable<Method>[])new TypeVariable[0];
255 }
256
257 /**
258 * Returns a {@code Class} object that represents the formal return type
259 * of the method represented by this {@code Method} object.
260 *
261 * @return the return type for the method this object represents
262 */
263 public Class<?> getReturnType() {
264 return returnType;
265 }
266
267 /**
268 * Returns a {@code Type} object that represents the formal return
269 * type of the method represented by this {@code Method} object.
270 *
271 * <p>If the return type is a parameterized type,
272 * the {@code Type} object returned must accurately reflect
273 * the actual type parameters used in the source code.
274 *
275 * <p>If the return type is a type variable or a parameterized type, it
276 * is created. Otherwise, it is resolved.
277 *
278 * @return a {@code Type} object that represents the formal return
279 * type of the underlying method
280 * @throws GenericSignatureFormatError
281 * if the generic method signature does not conform to the format
282 * specified in
283 * <cite>The Java™ Virtual Machine Specification</cite>
284 * @throws TypeNotPresentException if the underlying method's
285 * return type refers to a non-existent type declaration
286 * @throws MalformedParameterizedTypeException if the
287 * underlying method's return typed refers to a parameterized
288 * type that cannot be instantiated for any reason
289 * @since 1.5
290 */
291 public Type getGenericReturnType() {
292 if (getGenericSignature() != null) {
293 return getGenericInfo().getReturnType();
294 } else { return getReturnType();}
295 }
296
297 @Override
298 Class<?>[] getSharedParameterTypes() {
299 return parameterTypes;
300 }
301
302 /**
303 * {@inheritDoc}
304 */
305 @Override
306 public Class<?>[] getParameterTypes() {
307 return parameterTypes.clone();
308 }
309
310 /**
311 * {@inheritDoc}
312 * @since 1.8
313 */
314 public int getParameterCount() { return parameterTypes.length; }
315
316
317 /**
318 * {@inheritDoc}
319 * @throws GenericSignatureFormatError {@inheritDoc}
320 * @throws TypeNotPresentException {@inheritDoc}
321 * @throws MalformedParameterizedTypeException {@inheritDoc}
322 * @since 1.5
323 */
324 @Override
325 public Type[] getGenericParameterTypes() {
326 return super.getGenericParameterTypes();
327 }
328
329 /**
330 * {@inheritDoc}
331 */
332 @Override
333 public Class<?>[] getExceptionTypes() {
334 return exceptionTypes.clone();
335 }
336
337 /**
338 * {@inheritDoc}
339 * @throws GenericSignatureFormatError {@inheritDoc}
340 * @throws TypeNotPresentException {@inheritDoc}
341 * @throws MalformedParameterizedTypeException {@inheritDoc}
342 * @since 1.5
343 */
344 @Override
345 public Type[] getGenericExceptionTypes() {
346 return super.getGenericExceptionTypes();
347 }
348
349 /**
350 * Compares this {@code Method} against the specified object. Returns
351 * true if the objects are the same. Two {@code Methods} are the same if
352 * they were declared by the same class and have the same name
353 * and formal parameter types and return type.
354 */
355 public boolean equals(Object obj) {
356 if (obj != null && obj instanceof Method) {
357 Method other = (Method)obj;
358 if ((getDeclaringClass() == other.getDeclaringClass())
359 && (getName() == other.getName())) {
360 if (!returnType.equals(other.getReturnType()))
361 return false;
362 return equalParamTypes(parameterTypes, other.parameterTypes);
363 }
364 }
365 return false;
366 }
367
368 /**
369 * Returns a hashcode for this {@code Method}. The hashcode is computed
370 * as the exclusive-or of the hashcodes for the underlying
371 * method's declaring class name and the method's name.
372 */
373 public int hashCode() {
374 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
375 }
376
377 /**
378 * Returns a string describing this {@code Method}. The string is
379 * formatted as the method access modifiers, if any, followed by
380 * the method return type, followed by a space, followed by the
381 * class declaring the method, followed by a period, followed by
382 * the method name, followed by a parenthesized, comma-separated
383 * list of the method's formal parameter types. If the method
384 * throws checked exceptions, the parameter list is followed by a
385 * space, followed by the word "{@code throws}" followed by a
386 * comma-separated list of the thrown exception types.
387 * For example:
388 * <pre>
389 * public boolean java.lang.Object.equals(java.lang.Object)
390 * </pre>
391 *
392 * <p>The access modifiers are placed in canonical order as
393 * specified by "The Java Language Specification". This is
394 * {@code public}, {@code protected} or {@code private} first,
395 * and then other modifiers in the following order:
396 * {@code abstract}, {@code default}, {@code static}, {@code final},
397 * {@code synchronized}, {@code native}, {@code strictfp}.
398 *
399 * @return a string describing this {@code Method}
400 *
401 * @jls 8.4.3 Method Modifiers
402 * @jls 9.4 Method Declarations
403 * @jls 9.6.1 Annotation Type Elements
404 */
405 public String toString() {
406 return sharedToString(Modifier.methodModifiers(),
407 isDefault(),
408 parameterTypes,
409 exceptionTypes);
410 }
411
412 @Override
413 void specificToStringHeader(StringBuilder sb) {
414 sb.append(getReturnType().getTypeName()).append(' ');
415 sb.append(getDeclaringClass().getTypeName()).append('.');
416 sb.append(getName());
417 }
418
419 /**
420 * Returns a string describing this {@code Method}, including
421 * type parameters. The string is formatted as the method access
422 * modifiers, if any, followed by an angle-bracketed
423 * comma-separated list of the method's type parameters, if any,
424 * followed by the method's generic return type, followed by a
425 * space, followed by the class declaring the method, followed by
426 * a period, followed by the method name, followed by a
427 * parenthesized, comma-separated list of the method's generic
428 * formal parameter types.
429 *
430 * If this method was declared to take a variable number of
431 * arguments, instead of denoting the last parameter as
432 * "<code><i>Type</i>[]</code>", it is denoted as
433 * "<code><i>Type</i>...</code>".
434 *
435 * A space is used to separate access modifiers from one another
436 * and from the type parameters or return type. If there are no
437 * type parameters, the type parameter list is elided; if the type
438 * parameter list is present, a space separates the list from the
439 * class name. If the method is declared to throw exceptions, the
440 * parameter list is followed by a space, followed by the word
441 * "{@code throws}" followed by a comma-separated list of the generic
442 * thrown exception types.
443 *
444 * <p>The access modifiers are placed in canonical order as
445 * specified by "The Java Language Specification". This is
446 * {@code public}, {@code protected} or {@code private} first,
447 * and then other modifiers in the following order:
448 * {@code abstract}, {@code default}, {@code static}, {@code final},
449 * {@code synchronized}, {@code native}, {@code strictfp}.
450 *
451 * @return a string describing this {@code Method},
452 * include type parameters
453 *
454 * @since 1.5
455 *
456 * @jls 8.4.3 Method Modifiers
457 * @jls 9.4 Method Declarations
458 * @jls 9.6.1 Annotation Type Elements
459 */
460 @Override
461 public String toGenericString() {
462 return sharedToGenericString(Modifier.methodModifiers(), isDefault());
463 }
464
465 @Override
466 void specificToGenericStringHeader(StringBuilder sb) {
467 Type genRetType = getGenericReturnType();
468 sb.append(genRetType.getTypeName()).append(' ');
469 sb.append(getDeclaringClass().getTypeName()).append('.');
470 sb.append(getName());
471 }
472
473 /**
474 * Invokes the underlying method represented by this {@code Method}
475 * object, on the specified object with the specified parameters.
476 * Individual parameters are automatically unwrapped to match
477 * primitive formal parameters, and both primitive and reference
478 * parameters are subject to method invocation conversions as
479 * necessary.
480 *
481 * <p>If the underlying method is static, then the specified {@code obj}
482 * argument is ignored. It may be null.
483 *
484 * <p>If the number of formal parameters required by the underlying method is
485 * 0, the supplied {@code args} array may be of length 0 or null.
486 *
487 * <p>If the underlying method is an instance method, it is invoked
488 * using dynamic method lookup as documented in The Java Language
489 * Specification, Second Edition, section 15.12.4.4; in particular,
490 * overriding based on the runtime type of the target object will occur.
491 *
492 * <p>If the underlying method is static, the class that declared
493 * the method is initialized if it has not already been initialized.
494 *
495 * <p>If the method completes normally, the value it returns is
496 * returned to the caller of invoke; if the value has a primitive
497 * type, it is first appropriately wrapped in an object. However,
498 * if the value has the type of an array of a primitive type, the
499 * elements of the array are <i>not</i> wrapped in objects; in
500 * other words, an array of primitive type is returned. If the
501 * underlying method return type is void, the invocation returns
502 * null.
503 *
504 * @param obj the object the underlying method is invoked from
505 * @param args the arguments used for the method call
506 * @return the result of dispatching the method represented by
507 * this object on {@code obj} with parameters
508 * {@code args}
509 *
510 * @exception IllegalAccessException if this {@code Method} object
511 * is enforcing Java language access control and the underlying
512 * method is inaccessible.
513 * @exception IllegalArgumentException if the method is an
514 * instance method and the specified object argument
515 * is not an instance of the class or interface
516 * declaring the underlying method (or of a subclass
517 * or implementor thereof); if the number of actual
518 * and formal parameters differ; if an unwrapping
519 * conversion for primitive arguments fails; or if,
520 * after possible unwrapping, a parameter value
521 * cannot be converted to the corresponding formal
522 * parameter type by a method invocation conversion.
523 * @exception InvocationTargetException if the underlying method
524 * throws an exception.
525 * @exception NullPointerException if the specified object is null
526 * and the method is an instance method.
527 * @exception ExceptionInInitializerError if the initialization
528 * provoked by this method fails.
529 */
530 @CallerSensitive
531 @ForceInline // to ensure Reflection.getCallerClass optimization
532 @HotSpotIntrinsicCandidate
533 public Object invoke(Object obj, Object... args)
534 throws IllegalAccessException, IllegalArgumentException,
535 InvocationTargetException
536 {
537 if (!override) {
538 Class<?> caller = Reflection.getCallerClass();
539 checkAccess(caller, clazz,
540 Modifier.isStatic(modifiers) ? null : obj.getClass(),
541 modifiers);
542 }
543 MethodAccessor ma = methodAccessor; // read volatile
544 if (ma == null) {
545 ma = acquireMethodAccessor();
546 }
547 return ma.invoke(obj, args);
548 }
549
550 /**
551 * Returns {@code true} if this method is a bridge
552 * method; returns {@code false} otherwise.
553 *
554 * @return true if and only if this method is a bridge
555 * method as defined by the Java Language Specification.
556 * @since 1.5
557 */
558 public boolean isBridge() {
559 return (getModifiers() & Modifier.BRIDGE) != 0;
560 }
561
562 /**
563 * {@inheritDoc}
564 * @since 1.5
565 */
566 @Override
567 public boolean isVarArgs() {
568 return super.isVarArgs();
569 }
570
571 /**
572 * {@inheritDoc}
573 * @jls 13.1 The Form of a Binary
574 * @since 1.5
575 */
576 @Override
577 public boolean isSynthetic() {
578 return super.isSynthetic();
579 }
580
581 /**
582 * Returns {@code true} if this method is a default
583 * method; returns {@code false} otherwise.
584 *
585 * A default method is a public non-abstract instance method, that
586 * is, a non-static method with a body, declared in an interface
587 * type.
588 *
589 * @return true if and only if this method is a default
590 * method as defined by the Java Language Specification.
591 * @since 1.8
592 */
593 public boolean isDefault() {
594 // Default methods are public non-abstract instance methods
595 // declared in an interface.
596 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) ==
597 Modifier.PUBLIC) && getDeclaringClass().isInterface();
598 }
599
600 // NOTE that there is no synchronization used here. It is correct
601 // (though not efficient) to generate more than one MethodAccessor
602 // for a given Method. However, avoiding synchronization will
603 // probably make the implementation more scalable.
604 private MethodAccessor acquireMethodAccessor() {
605 // First check to see if one has been created yet, and take it
606 // if so
607 MethodAccessor tmp = null;
608 if (root != null) tmp = root.getMethodAccessor();
609 if (tmp != null) {
610 methodAccessor = tmp;
611 } else {
612 // Otherwise fabricate one and propagate it up to the root
613 tmp = reflectionFactory.newMethodAccessor(this);
614 setMethodAccessor(tmp);
615 }
616
617 return tmp;
618 }
619
620 // Returns MethodAccessor for this Method object, not looking up
621 // the chain to the root
622 MethodAccessor getMethodAccessor() {
623 return methodAccessor;
624 }
625
626 // Sets the MethodAccessor for this Method object and
627 // (recursively) its root
628 void setMethodAccessor(MethodAccessor accessor) {
629 methodAccessor = accessor;
630 // Propagate up
631 if (root != null) {
632 root.setMethodAccessor(accessor);
633 }
634 }
635
636 /**
637 * Returns the default value for the annotation member represented by
638 * this {@code Method} instance. If the member is of a primitive type,
639 * an instance of the corresponding wrapper type is returned. Returns
640 * null if no default is associated with the member, or if the method
641 * instance does not represent a declared member of an annotation type.
642 *
643 * @return the default value for the annotation member represented
644 * by this {@code Method} instance.
645 * @throws TypeNotPresentException if the annotation is of type
646 * {@link Class} and no definition can be found for the
647 * default class value.
648 * @since 1.5
649 */
650 public Object getDefaultValue() {
651 if (annotationDefault == null)
652 return null;
653 Class<?> memberType = AnnotationType.invocationHandlerReturnType(
654 getReturnType());
655 Object result = AnnotationParser.parseMemberValue(
656 memberType, ByteBuffer.wrap(annotationDefault),
657 SharedSecrets.getJavaLangAccess().
658 getConstantPool(getDeclaringClass()),
659 getDeclaringClass());
660 if (result instanceof ExceptionProxy) {
661 if (result instanceof TypeNotPresentExceptionProxy) {
662 TypeNotPresentExceptionProxy proxy = (TypeNotPresentExceptionProxy)result;
663 throw new TypeNotPresentException(proxy.typeName(), proxy.getCause());
664 }
665 throw new AnnotationFormatError("Invalid default: " + this);
666 }
667 return result;
668 }
669
670 /**
671 * {@inheritDoc}
672 * @throws NullPointerException {@inheritDoc}
673 * @since 1.5
674 */
675 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
676 return super.getAnnotation(annotationClass);
677 }
678
679 /**
680 * {@inheritDoc}
681 * @since 1.5
682 */
683 public Annotation[] getDeclaredAnnotations() {
684 return super.getDeclaredAnnotations();
685 }
686
687 /**
688 * {@inheritDoc}
689 * @since 1.5
690 */
691 @Override
692 public Annotation[][] getParameterAnnotations() {
693 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
694 }
695
696 /**
697 * {@inheritDoc}
698 * @since 1.8
699 */
700 @Override
701 public AnnotatedType getAnnotatedReturnType() {
702 return getAnnotatedReturnType0(getGenericReturnType());
703 }
704
705 @Override
706 void handleParameterNumberMismatch(int resultLength, int numParameters) {
707 throw new AnnotationFormatError("Parameter annotations don't match number of parameters");
708 }
709 }