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