1 /*
2 * Copyright (c) 1996, 2018, 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.access.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 import java.util.StringJoiner;
46
47 /**
48 * A {@code Method} provides information about, and access to, a single method
49 * on a class or interface. The reflected method may be a class method
50 * or an instance method (including an abstract method).
51 *
52 * <p>A {@code Method} permits widening conversions to occur when matching the
53 * actual parameters to invoke with the underlying method's formal
54 * parameters, but it throws an {@code IllegalArgumentException} if a
55 * narrowing conversion would occur.
56 *
57 * @see Member
58 * @see java.lang.Class
59 * @see java.lang.Class#getMethods()
60 * @see java.lang.Class#getMethod(String, Class[])
61 * @see java.lang.Class#getDeclaredMethods()
62 * @see java.lang.Class#getDeclaredMethod(String, Class[])
63 *
64 * @author Kenneth Russell
65 * @author Nakul Saraiya
66 * @since 1.1
67 */
68 public final class Method extends Executable {
69 private Class<?> clazz;
70 private int slot;
71 // This is guaranteed to be interned by the VM in the 1.4
72 // reflection implementation
73 private String name;
74 private Class<?> returnType;
75 private Class<?>[] parameterTypes;
76 private Class<?>[] exceptionTypes;
77 private int modifiers;
78 // Generics and annotations support
79 private transient String signature;
80 // generic info repository; lazily initialized
81 private transient MethodRepository genericInfo;
82 private byte[] annotations;
83 private byte[] parameterAnnotations;
84 private byte[] annotationDefault;
85 private volatile MethodAccessor methodAccessor;
86 // For sharing of MethodAccessors. This branching structure is
87 // currently only two levels deep (i.e., one root Method and
88 // potentially many Method objects pointing to it.)
89 //
90 // If this branching structure would ever contain cycles, deadlocks can
91 // occur in annotation code.
92 private Method root;
93
94 // Generics infrastructure
95 private String getGenericSignature() {return signature;}
96
97 // Accessor for factory
98 private GenericsFactory getFactory() {
99 // create scope and factory
100 return CoreReflectionFactory.make(this, MethodScope.make(this));
101 }
102
103 // Accessor for generic info repository
104 @Override
105 MethodRepository getGenericInfo() {
106 // lazily initialize repository if necessary
107 if (genericInfo == null) {
108 // create and cache generic info repository
109 genericInfo = MethodRepository.make(getGenericSignature(),
110 getFactory());
111 }
112 return genericInfo; //return cached repository
113 }
114
115 /**
116 * Package-private constructor used by ReflectAccess to enable
117 * instantiation of these objects in Java code from the java.lang
118 * package via sun.reflect.LangReflectAccess.
119 */
120 Method(Class<?> declaringClass,
121 String name,
122 Class<?>[] parameterTypes,
123 Class<?> returnType,
124 Class<?>[] checkedExceptions,
125 int modifiers,
126 int slot,
127 String signature,
128 byte[] annotations,
129 byte[] parameterAnnotations,
130 byte[] annotationDefault) {
131 this.clazz = declaringClass;
132 this.name = name;
133 this.parameterTypes = parameterTypes;
134 this.returnType = returnType;
135 this.exceptionTypes = checkedExceptions;
136 this.modifiers = modifiers;
137 this.slot = slot;
138 this.signature = signature;
139 this.annotations = annotations;
140 this.parameterAnnotations = parameterAnnotations;
141 this.annotationDefault = annotationDefault;
142 }
143
144 /**
145 * Package-private routine (exposed to java.lang.Class via
146 * ReflectAccess) which returns a copy of this Method. The copy's
147 * "root" field points to this Method.
148 */
149 Method copy() {
150 // This routine enables sharing of MethodAccessor objects
151 // among Method objects which refer to the same underlying
152 // method in the VM. (All of this contortion is only necessary
153 // because of the "accessibility" bit in AccessibleObject,
154 // which implicitly requires that new java.lang.reflect
155 // objects be fabricated for each reflective call on Class
156 // objects.)
157 if (this.root != null)
158 throw new IllegalArgumentException("Can not copy a non-root Method");
159
160 Method res = new Method(clazz, name, parameterTypes, returnType,
161 exceptionTypes, modifiers, slot, signature,
162 annotations, parameterAnnotations, annotationDefault);
163 res.root = this;
164 // Might as well eagerly propagate this if already present
165 res.methodAccessor = methodAccessor;
166 return res;
167 }
168
169 /**
170 * Make a copy of a leaf method.
171 */
172 Method leafCopy() {
173 if (this.root == null)
174 throw new IllegalArgumentException("Can only leafCopy a non-root Method");
175
176 Method res = new Method(clazz, name, parameterTypes, returnType,
177 exceptionTypes, modifiers, slot, signature,
178 annotations, parameterAnnotations, annotationDefault);
179 res.root = root;
180 res.methodAccessor = methodAccessor;
181 return res;
182 }
183
184 /**
185 * @throws InaccessibleObjectException {@inheritDoc}
186 * @throws SecurityException {@inheritDoc}
187 */
188 @Override
189 @CallerSensitive
190 public void setAccessible(boolean flag) {
191 AccessibleObject.checkPermission();
192 if (flag) checkCanSetAccessible(Reflection.getCallerClass());
193 setAccessible0(flag);
194 }
195
196 @Override
197 void checkCanSetAccessible(Class<?> caller) {
198 checkCanSetAccessible(caller, clazz);
199 }
200
201 @Override
202 Method getRoot() {
203 return root;
204 }
205
206 @Override
207 boolean hasGenericInformation() {
208 return (getGenericSignature() != null);
209 }
210
211 @Override
212 byte[] getAnnotationBytes() {
213 return annotations;
214 }
215
216 /**
217 * Returns the {@code Class} object representing the class or interface
218 * that declares the method represented by this object.
219 *
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 @Override
303 Class<?>[] getSharedExceptionTypes() {
304 return exceptionTypes;
305 }
306
307 /**
308 * {@inheritDoc}
309 */
310 @Override
311 public Class<?>[] getParameterTypes() {
312 return parameterTypes.clone();
313 }
314
315 /**
316 * {@inheritDoc}
317 * @since 1.8
318 */
319 public int getParameterCount() { return parameterTypes.length; }
320
321
322 /**
323 * {@inheritDoc}
324 * @throws GenericSignatureFormatError {@inheritDoc}
325 * @throws TypeNotPresentException {@inheritDoc}
326 * @throws MalformedParameterizedTypeException {@inheritDoc}
327 * @since 1.5
328 */
329 @Override
330 public Type[] getGenericParameterTypes() {
331 return super.getGenericParameterTypes();
332 }
333
334 /**
335 * {@inheritDoc}
336 */
337 @Override
338 public Class<?>[] getExceptionTypes() {
339 return exceptionTypes.clone();
340 }
341
342 /**
343 * {@inheritDoc}
344 * @throws GenericSignatureFormatError {@inheritDoc}
345 * @throws TypeNotPresentException {@inheritDoc}
346 * @throws MalformedParameterizedTypeException {@inheritDoc}
347 * @since 1.5
348 */
349 @Override
350 public Type[] getGenericExceptionTypes() {
351 return super.getGenericExceptionTypes();
352 }
353
354 /**
355 * Compares this {@code Method} against the specified object. Returns
356 * true if the objects are the same. Two {@code Methods} are the same if
357 * they were declared by the same class and have the same name
358 * and formal parameter types and return type.
359 */
360 public boolean equals(Object obj) {
361 if (obj != null && obj instanceof Method) {
362 Method other = (Method)obj;
363 if ((getDeclaringClass() == other.getDeclaringClass())
364 && (getName() == other.getName())) {
365 if (!returnType.equals(other.getReturnType()))
366 return false;
367 return equalParamTypes(parameterTypes, other.parameterTypes);
368 }
369 }
370 return false;
371 }
372
373 /**
374 * Returns a hashcode for this {@code Method}. The hashcode is computed
375 * as the exclusive-or of the hashcodes for the underlying
376 * method's declaring class name and the method's name.
377 */
378 public int hashCode() {
379 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
380 }
381
382 /**
383 * Returns a string describing this {@code Method}. The string is
384 * formatted as the method access modifiers, if any, followed by
385 * the method return type, followed by a space, followed by the
386 * class declaring the method, followed by a period, followed by
387 * the method name, followed by a parenthesized, comma-separated
388 * list of the method's formal parameter types. If the method
389 * throws checked exceptions, the parameter list is followed by a
390 * space, followed by the word "{@code throws}" followed by a
391 * comma-separated list of the thrown exception types.
392 * For example:
393 * <pre>
394 * public boolean java.lang.Object.equals(java.lang.Object)
395 * </pre>
396 *
397 * <p>The access modifiers are placed in canonical order as
398 * specified by "The Java Language Specification". This is
399 * {@code public}, {@code protected} or {@code private} first,
400 * and then other modifiers in the following order:
401 * {@code abstract}, {@code default}, {@code static}, {@code final},
402 * {@code synchronized}, {@code native}, {@code strictfp}.
403 *
404 * @return a string describing this {@code Method}
405 *
406 * @jls 8.4.3 Method Modifiers
407 * @jls 9.4 Method Declarations
408 * @jls 9.6.1 Annotation Type Elements
409 */
410 public String toString() {
411 return sharedToString(Modifier.methodModifiers(),
412 isDefault(),
413 parameterTypes,
414 exceptionTypes);
415 }
416
417 @Override
418 void specificToStringHeader(StringBuilder sb) {
419 sb.append(getReturnType().getTypeName()).append(' ');
420 sb.append(getDeclaringClass().getTypeName()).append('.');
421 sb.append(getName());
422 }
423
424 @Override
425 String toShortString() {
426 StringBuilder sb = new StringBuilder("method ");
427 sb.append(getDeclaringClass().getTypeName()).append('.');
428 sb.append(getName());
429 sb.append('(');
430 StringJoiner sj = new StringJoiner(",");
431 for (Class<?> parameterType : getParameterTypes()) {
432 sj.add(parameterType.getTypeName());
433 }
434 sb.append(sj);
435 sb.append(')');
436 return sb.toString();
437 }
438
439 /**
440 * Returns a string describing this {@code Method}, including type
441 * parameters. The string is formatted as the method access
442 * modifiers, if any, followed by an angle-bracketed
443 * comma-separated list of the method's type parameters, if any,
444 * including informative bounds of the type parameters, if any,
445 * followed by the method's generic return type, followed by a
446 * space, followed by the class declaring the method, followed by
447 * a period, followed by the method name, followed by a
448 * parenthesized, comma-separated list of the method's generic
449 * formal parameter types.
450 *
451 * If this method was declared to take a variable number of
452 * arguments, instead of denoting the last parameter as
453 * "<code><i>Type</i>[]</code>", it is denoted as
454 * "<code><i>Type</i>...</code>".
455 *
456 * A space is used to separate access modifiers from one another
457 * and from the type parameters or return type. If there are no
458 * type parameters, the type parameter list is elided; if the type
459 * parameter list is present, a space separates the list from the
460 * class name. If the method is declared to throw exceptions, the
461 * parameter list is followed by a space, followed by the word
462 * "{@code throws}" followed by a comma-separated list of the generic
463 * thrown exception types.
464 *
465 * <p>The access modifiers are placed in canonical order as
466 * specified by "The Java Language Specification". This is
467 * {@code public}, {@code protected} or {@code private} first,
468 * and then other modifiers in the following order:
469 * {@code abstract}, {@code default}, {@code static}, {@code final},
470 * {@code synchronized}, {@code native}, {@code strictfp}.
471 *
472 * @return a string describing this {@code Method},
473 * include type parameters
474 *
475 * @since 1.5
476 *
477 * @jls 8.4.3 Method Modifiers
478 * @jls 9.4 Method Declarations
479 * @jls 9.6.1 Annotation Type Elements
480 */
481 @Override
482 public String toGenericString() {
483 return sharedToGenericString(Modifier.methodModifiers(), isDefault());
484 }
485
486 @Override
487 void specificToGenericStringHeader(StringBuilder sb) {
488 Type genRetType = getGenericReturnType();
489 sb.append(genRetType.getTypeName()).append(' ');
490 sb.append(getDeclaringClass().getTypeName()).append('.');
491 sb.append(getName());
492 }
493
494 /**
495 * Invokes the underlying method represented by this {@code Method}
496 * object, on the specified object with the specified parameters.
497 * Individual parameters are automatically unwrapped to match
498 * primitive formal parameters, and both primitive and reference
499 * parameters are subject to method invocation conversions as
500 * necessary.
501 *
502 * <p>If the underlying method is static, then the specified {@code obj}
503 * argument is ignored. It may be null.
504 *
505 * <p>If the number of formal parameters required by the underlying method is
506 * 0, the supplied {@code args} array may be of length 0 or null.
507 *
508 * <p>If the underlying method is an instance method, it is invoked
509 * using dynamic method lookup as documented in The Java Language
510 * Specification, section 15.12.4.4; in particular,
511 * overriding based on the runtime type of the target object may occur.
512 *
513 * <p>If the underlying method is static, the class that declared
514 * the method is initialized if it has not already been initialized.
515 *
516 * <p>If the method completes normally, the value it returns is
517 * returned to the caller of invoke; if the value has a primitive
518 * type, it is first appropriately wrapped in an object. However,
519 * if the value has the type of an array of a primitive type, the
520 * elements of the array are <i>not</i> wrapped in objects; in
521 * other words, an array of primitive type is returned. If the
522 * underlying method return type is void, the invocation returns
523 * null.
524 *
525 * @param obj the object the underlying method is invoked from
526 * @param args the arguments used for the method call
527 * @return the result of dispatching the method represented by
528 * this object on {@code obj} with parameters
529 * {@code args}
530 *
531 * @exception IllegalAccessException if this {@code Method} object
532 * is enforcing Java language access control and the underlying
533 * method is inaccessible.
534 * @exception IllegalArgumentException if the method is an
535 * instance method and the specified object argument
536 * is not an instance of the class or interface
537 * declaring the underlying method (or of a subclass
538 * or implementor thereof); if the number of actual
539 * and formal parameters differ; if an unwrapping
540 * conversion for primitive arguments fails; or if,
541 * after possible unwrapping, a parameter value
542 * cannot be converted to the corresponding formal
543 * parameter type by a method invocation conversion.
544 * @exception InvocationTargetException if the underlying method
545 * throws an exception.
546 * @exception NullPointerException if the specified object is null
547 * and the method is an instance method.
548 * @exception ExceptionInInitializerError if the initialization
549 * provoked by this method fails.
550 */
551 @CallerSensitive
552 @ForceInline // to ensure Reflection.getCallerClass optimization
553 @HotSpotIntrinsicCandidate
554 public Object invoke(Object obj, Object... args)
555 throws IllegalAccessException, IllegalArgumentException,
556 InvocationTargetException
557 {
558 if (!override) {
559 Class<?> caller = Reflection.getCallerClass();
560 checkAccess(caller, clazz,
561 Modifier.isStatic(modifiers) ? null : obj.getClass(),
562 modifiers);
563 }
564 MethodAccessor ma = methodAccessor; // read volatile
565 if (ma == null) {
566 ma = acquireMethodAccessor();
567 }
568 return ma.invoke(obj, args);
569 }
570
571 /**
572 * Returns {@code true} if this method is a bridge
573 * method; returns {@code false} otherwise.
574 *
575 * @return true if and only if this method is a bridge
576 * method as defined by the Java Language Specification.
577 * @since 1.5
578 */
579 public boolean isBridge() {
580 return (getModifiers() & Modifier.BRIDGE) != 0;
581 }
582
583 /**
584 * {@inheritDoc}
585 * @since 1.5
586 */
587 @Override
588 public boolean isVarArgs() {
589 return super.isVarArgs();
590 }
591
592 /**
593 * {@inheritDoc}
594 * @jls 13.1 The Form of a Binary
595 * @since 1.5
596 */
597 @Override
598 public boolean isSynthetic() {
599 return super.isSynthetic();
600 }
601
602 /**
603 * Returns {@code true} if this method is a default
604 * method; returns {@code false} otherwise.
605 *
606 * A default method is a public non-abstract instance method, that
607 * is, a non-static method with a body, declared in an interface
608 * type.
609 *
610 * @return true if and only if this method is a default
611 * method as defined by the Java Language Specification.
612 * @since 1.8
613 */
614 public boolean isDefault() {
615 // Default methods are public non-abstract instance methods
616 // declared in an interface.
617 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) ==
618 Modifier.PUBLIC) && getDeclaringClass().isInterface();
619 }
620
621 // NOTE that there is no synchronization used here. It is correct
622 // (though not efficient) to generate more than one MethodAccessor
623 // for a given Method. However, avoiding synchronization will
624 // probably make the implementation more scalable.
625 private MethodAccessor acquireMethodAccessor() {
626 // First check to see if one has been created yet, and take it
627 // if so
628 MethodAccessor tmp = null;
629 if (root != null) tmp = root.getMethodAccessor();
630 if (tmp != null) {
631 methodAccessor = tmp;
632 } else {
633 // Otherwise fabricate one and propagate it up to the root
634 tmp = reflectionFactory.newMethodAccessor(this);
635 setMethodAccessor(tmp);
636 }
637
638 return tmp;
639 }
640
641 // Returns MethodAccessor for this Method object, not looking up
642 // the chain to the root
643 MethodAccessor getMethodAccessor() {
644 return methodAccessor;
645 }
646
647 // Sets the MethodAccessor for this Method object and
648 // (recursively) its root
649 void setMethodAccessor(MethodAccessor accessor) {
650 methodAccessor = accessor;
651 // Propagate up
652 if (root != null) {
653 root.setMethodAccessor(accessor);
654 }
655 }
656
657 /**
658 * Returns the default value for the annotation member represented by
659 * this {@code Method} instance. If the member is of a primitive type,
660 * an instance of the corresponding wrapper type is returned. Returns
661 * null if no default is associated with the member, or if the method
662 * instance does not represent a declared member of an annotation type.
663 *
664 * @return the default value for the annotation member represented
665 * by this {@code Method} instance.
666 * @throws TypeNotPresentException if the annotation is of type
667 * {@link Class} and no definition can be found for the
668 * default class value.
669 * @since 1.5
670 */
671 public Object getDefaultValue() {
672 if (annotationDefault == null)
673 return null;
674 Class<?> memberType = AnnotationType.invocationHandlerReturnType(
675 getReturnType());
676 Object result = AnnotationParser.parseMemberValue(
677 memberType, ByteBuffer.wrap(annotationDefault),
678 SharedSecrets.getJavaLangAccess().
679 getConstantPool(getDeclaringClass()),
680 getDeclaringClass());
681 if (result instanceof ExceptionProxy) {
682 if (result instanceof TypeNotPresentExceptionProxy) {
683 TypeNotPresentExceptionProxy proxy = (TypeNotPresentExceptionProxy)result;
684 throw new TypeNotPresentException(proxy.typeName(), proxy.getCause());
685 }
686 throw new AnnotationFormatError("Invalid default: " + this);
687 }
688 return result;
689 }
690
691 /**
692 * {@inheritDoc}
693 * @throws NullPointerException {@inheritDoc}
694 * @since 1.5
695 */
696 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
697 return super.getAnnotation(annotationClass);
698 }
699
700 /**
701 * {@inheritDoc}
702 * @since 1.5
703 */
704 public Annotation[] getDeclaredAnnotations() {
705 return super.getDeclaredAnnotations();
706 }
707
708 /**
709 * {@inheritDoc}
710 * @since 1.5
711 */
712 @Override
713 public Annotation[][] getParameterAnnotations() {
714 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
715 }
716
717 /**
718 * {@inheritDoc}
719 * @since 1.8
720 */
721 @Override
722 public AnnotatedType getAnnotatedReturnType() {
723 return getAnnotatedReturnType0(getGenericReturnType());
724 }
725
726 @Override
727 boolean handleParameterNumberMismatch(int resultLength, int numParameters) {
728 throw new AnnotationFormatError("Parameter annotations don't match number of parameters");
729 }
730 }