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.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 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 /**
202 * Used by Excecutable for annotation sharing.
203 */
204 @Override
205 Executable getRoot() {
206 return root;
207 }
208
209 @Override
210 boolean hasGenericInformation() {
211 return (getGenericSignature() != null);
212 }
213
214 @Override
215 byte[] getAnnotationBytes() {
216 return annotations;
217 }
218
219 /**
220 * Returns the {@code Class} object representing the class or interface
221 * that declares the method represented by this object.
222 */
223 @Override
224 public Class<?> getDeclaringClass() {
225 return clazz;
226 }
227
228 /**
229 * Returns the name of the method represented by this {@code Method}
230 * object, as a {@code String}.
231 */
232 @Override
233 public String getName() {
234 return name;
235 }
236
237 /**
238 * {@inheritDoc}
239 */
240 @Override
241 public int getModifiers() {
242 return modifiers;
243 }
244
245 /**
246 * {@inheritDoc}
247 * @throws GenericSignatureFormatError {@inheritDoc}
248 * @since 1.5
249 */
250 @Override
251 @SuppressWarnings({"rawtypes", "unchecked"})
252 public TypeVariable<Method>[] getTypeParameters() {
253 if (getGenericSignature() != null)
254 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters();
255 else
256 return (TypeVariable<Method>[])new TypeVariable[0];
257 }
258
259 /**
260 * Returns a {@code Class} object that represents the formal return type
261 * of the method represented by this {@code Method} object.
262 *
263 * @return the return type for the method this object represents
264 */
265 public Class<?> getReturnType() {
266 return returnType;
267 }
268
269 /**
270 * Returns a {@code Type} object that represents the formal return
271 * type of the method represented by this {@code Method} object.
272 *
273 * <p>If the return type is a parameterized type,
274 * the {@code Type} object returned must accurately reflect
275 * the actual type parameters used in the source code.
276 *
277 * <p>If the return type is a type variable or a parameterized type, it
278 * is created. Otherwise, it is resolved.
279 *
280 * @return a {@code Type} object that represents the formal return
281 * type of the underlying method
282 * @throws GenericSignatureFormatError
283 * if the generic method signature does not conform to the format
284 * specified in
285 * <cite>The Java™ Virtual Machine Specification</cite>
286 * @throws TypeNotPresentException if the underlying method's
287 * return type refers to a non-existent type declaration
288 * @throws MalformedParameterizedTypeException if the
289 * underlying method's return typed refers to a parameterized
290 * type that cannot be instantiated for any reason
291 * @since 1.5
292 */
293 public Type getGenericReturnType() {
294 if (getGenericSignature() != null) {
295 return getGenericInfo().getReturnType();
296 } else { return getReturnType();}
297 }
298
299 @Override
300 Class<?>[] getSharedParameterTypes() {
301 return parameterTypes;
302 }
303
304 @Override
305 Class<?>[] getSharedExceptionTypes() {
306 return exceptionTypes;
307 }
308
309 /**
310 * {@inheritDoc}
311 */
312 @Override
313 public Class<?>[] getParameterTypes() {
314 return parameterTypes.clone();
315 }
316
317 /**
318 * {@inheritDoc}
319 * @since 1.8
320 */
321 public int getParameterCount() { return parameterTypes.length; }
322
323
324 /**
325 * {@inheritDoc}
326 * @throws GenericSignatureFormatError {@inheritDoc}
327 * @throws TypeNotPresentException {@inheritDoc}
328 * @throws MalformedParameterizedTypeException {@inheritDoc}
329 * @since 1.5
330 */
331 @Override
332 public Type[] getGenericParameterTypes() {
333 return super.getGenericParameterTypes();
334 }
335
336 /**
337 * {@inheritDoc}
338 */
339 @Override
340 public Class<?>[] getExceptionTypes() {
341 return exceptionTypes.clone();
342 }
343
344 /**
345 * {@inheritDoc}
346 * @throws GenericSignatureFormatError {@inheritDoc}
347 * @throws TypeNotPresentException {@inheritDoc}
348 * @throws MalformedParameterizedTypeException {@inheritDoc}
349 * @since 1.5
350 */
351 @Override
352 public Type[] getGenericExceptionTypes() {
353 return super.getGenericExceptionTypes();
354 }
355
356 /**
357 * Compares this {@code Method} against the specified object. Returns
358 * true if the objects are the same. Two {@code Methods} are the same if
359 * they were declared by the same class and have the same name
360 * and formal parameter types and return type.
361 */
362 public boolean equals(Object obj) {
363 if (obj != null && obj instanceof Method) {
364 Method other = (Method)obj;
365 if ((getDeclaringClass() == other.getDeclaringClass())
366 && (getName() == other.getName())) {
367 if (!returnType.equals(other.getReturnType()))
368 return false;
369 return equalParamTypes(parameterTypes, other.parameterTypes);
370 }
371 }
372 return false;
373 }
374
375 /**
376 * Returns a hashcode for this {@code Method}. The hashcode is computed
377 * as the exclusive-or of the hashcodes for the underlying
378 * method's declaring class name and the method's name.
379 */
380 public int hashCode() {
381 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
382 }
383
384 /**
385 * Returns a string describing this {@code Method}. The string is
386 * formatted as the method access modifiers, if any, followed by
387 * the method return type, followed by a space, followed by the
388 * class declaring the method, followed by a period, followed by
389 * the method name, followed by a parenthesized, comma-separated
390 * list of the method's formal parameter types. If the method
391 * throws checked exceptions, the parameter list is followed by a
392 * space, followed by the word "{@code throws}" followed by a
393 * comma-separated list of the thrown exception types.
394 * For example:
395 * <pre>
396 * public boolean java.lang.Object.equals(java.lang.Object)
397 * </pre>
398 *
399 * <p>The access modifiers are placed in canonical order as
400 * specified by "The Java Language Specification". This is
401 * {@code public}, {@code protected} or {@code private} first,
402 * and then other modifiers in the following order:
403 * {@code abstract}, {@code default}, {@code static}, {@code final},
404 * {@code synchronized}, {@code native}, {@code strictfp}.
405 *
406 * @return a string describing this {@code Method}
407 *
408 * @jls 8.4.3 Method Modifiers
409 * @jls 9.4 Method Declarations
410 * @jls 9.6.1 Annotation Type Elements
411 */
412 public String toString() {
413 return sharedToString(Modifier.methodModifiers(),
414 isDefault(),
415 parameterTypes,
416 exceptionTypes);
417 }
418
419 @Override
420 void specificToStringHeader(StringBuilder sb) {
421 sb.append(getReturnType().getTypeName()).append(' ');
422 sb.append(getDeclaringClass().getTypeName()).append('.');
423 sb.append(getName());
424 }
425
426 @Override
427 String toShortString() {
428 StringBuilder sb = new StringBuilder("method ");
429 sb.append(getDeclaringClass().getTypeName()).append('.');
430 sb.append(getName());
431 sb.append('(');
432 StringJoiner sj = new StringJoiner(",");
433 for (Class<?> parameterType : getParameterTypes()) {
434 sj.add(parameterType.getTypeName());
435 }
436 sb.append(sj);
437 sb.append(')');
438 return sb.toString();
439 }
440
441 /**
442 * Returns a string describing this {@code Method}, including
443 * type parameters. The string is formatted as the method access
444 * modifiers, if any, followed by an angle-bracketed
445 * comma-separated list of the method's type parameters, if any,
446 * followed by the method's generic return type, followed by a
447 * space, followed by the class declaring the method, followed by
448 * a period, followed by the method name, followed by a
449 * parenthesized, comma-separated list of the method's generic
450 * formal parameter types.
451 *
452 * If this method was declared to take a variable number of
453 * arguments, instead of denoting the last parameter as
454 * "<code><i>Type</i>[]</code>", it is denoted as
455 * "<code><i>Type</i>...</code>".
456 *
457 * A space is used to separate access modifiers from one another
458 * and from the type parameters or return type. If there are no
459 * type parameters, the type parameter list is elided; if the type
460 * parameter list is present, a space separates the list from the
461 * class name. If the method is declared to throw exceptions, the
462 * parameter list is followed by a space, followed by the word
463 * "{@code throws}" followed by a comma-separated list of the generic
464 * thrown exception types.
465 *
466 * <p>The access modifiers are placed in canonical order as
467 * specified by "The Java Language Specification". This is
468 * {@code public}, {@code protected} or {@code private} first,
469 * and then other modifiers in the following order:
470 * {@code abstract}, {@code default}, {@code static}, {@code final},
471 * {@code synchronized}, {@code native}, {@code strictfp}.
472 *
473 * @return a string describing this {@code Method},
474 * include type parameters
475 *
476 * @since 1.5
477 *
478 * @jls 8.4.3 Method Modifiers
479 * @jls 9.4 Method Declarations
480 * @jls 9.6.1 Annotation Type Elements
481 */
482 @Override
483 public String toGenericString() {
484 return sharedToGenericString(Modifier.methodModifiers(), isDefault());
485 }
486
487 @Override
488 void specificToGenericStringHeader(StringBuilder sb) {
489 Type genRetType = getGenericReturnType();
490 sb.append(genRetType.getTypeName()).append(' ');
491 sb.append(getDeclaringClass().getTypeName()).append('.');
492 sb.append(getName());
493 }
494
495 /**
496 * Invokes the underlying method represented by this {@code Method}
497 * object, on the specified object with the specified parameters.
498 * Individual parameters are automatically unwrapped to match
499 * primitive formal parameters, and both primitive and reference
500 * parameters are subject to method invocation conversions as
501 * necessary.
502 *
503 * <p>If the underlying method is static, then the specified {@code obj}
504 * argument is ignored. It may be null.
505 *
506 * <p>If the number of formal parameters required by the underlying method is
507 * 0, the supplied {@code args} array may be of length 0 or null.
508 *
509 * <p>If the underlying method is an instance method, it is invoked
510 * using dynamic method lookup as documented in The Java Language
511 * Specification, section 15.12.4.4; in particular,
512 * overriding based on the runtime type of the target object may occur.
513 *
514 * <p>If the underlying method is static, the class that declared
515 * the method is initialized if it has not already been initialized.
516 *
517 * <p>If the method completes normally, the value it returns is
518 * returned to the caller of invoke; if the value has a primitive
519 * type, it is first appropriately wrapped in an object. However,
520 * if the value has the type of an array of a primitive type, the
521 * elements of the array are <i>not</i> wrapped in objects; in
522 * other words, an array of primitive type is returned. If the
523 * underlying method return type is void, the invocation returns
524 * null.
525 *
526 * @param obj the object the underlying method is invoked from
527 * @param args the arguments used for the method call
528 * @return the result of dispatching the method represented by
529 * this object on {@code obj} with parameters
530 * {@code args}
531 *
532 * @exception IllegalAccessException if this {@code Method} object
533 * is enforcing Java language access control and the underlying
534 * method is inaccessible.
535 * @exception IllegalArgumentException if the method is an
536 * instance method and the specified object argument
537 * is not an instance of the class or interface
538 * declaring the underlying method (or of a subclass
539 * or implementor thereof); if the number of actual
540 * and formal parameters differ; if an unwrapping
541 * conversion for primitive arguments fails; or if,
542 * after possible unwrapping, a parameter value
543 * cannot be converted to the corresponding formal
544 * parameter type by a method invocation conversion.
545 * @exception InvocationTargetException if the underlying method
546 * throws an exception.
547 * @exception NullPointerException if the specified object is null
548 * and the method is an instance method.
549 * @exception ExceptionInInitializerError if the initialization
550 * provoked by this method fails.
551 */
552 @CallerSensitive
553 @ForceInline // to ensure Reflection.getCallerClass optimization
554 @HotSpotIntrinsicCandidate
555 public Object invoke(Object obj, Object... args)
556 throws IllegalAccessException, IllegalArgumentException,
557 InvocationTargetException
558 {
559 if (!override) {
560 Class<?> caller = Reflection.getCallerClass();
561 checkAccess(caller, clazz,
562 Modifier.isStatic(modifiers) ? null : obj.getClass(),
563 modifiers);
564 }
565 MethodAccessor ma = methodAccessor; // read volatile
566 if (ma == null) {
567 ma = acquireMethodAccessor();
568 }
569 return ma.invoke(obj, args);
570 }
571
572 /**
573 * Returns {@code true} if this method is a bridge
574 * method; returns {@code false} otherwise.
575 *
576 * @return true if and only if this method is a bridge
577 * method as defined by the Java Language Specification.
578 * @since 1.5
579 */
580 public boolean isBridge() {
581 return (getModifiers() & Modifier.BRIDGE) != 0;
582 }
583
584 /**
585 * {@inheritDoc}
586 * @since 1.5
587 */
588 @Override
589 public boolean isVarArgs() {
590 return super.isVarArgs();
591 }
592
593 /**
594 * {@inheritDoc}
595 * @jls 13.1 The Form of a Binary
596 * @since 1.5
597 */
598 @Override
599 public boolean isSynthetic() {
600 return super.isSynthetic();
601 }
602
603 /**
604 * Returns {@code true} if this method is a default
605 * method; returns {@code false} otherwise.
606 *
607 * A default method is a public non-abstract instance method, that
608 * is, a non-static method with a body, declared in an interface
609 * type.
610 *
611 * @return true if and only if this method is a default
612 * method as defined by the Java Language Specification.
613 * @since 1.8
614 */
615 public boolean isDefault() {
616 // Default methods are public non-abstract instance methods
617 // declared in an interface.
618 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) ==
619 Modifier.PUBLIC) && getDeclaringClass().isInterface();
620 }
621
622 // NOTE that there is no synchronization used here. It is correct
623 // (though not efficient) to generate more than one MethodAccessor
624 // for a given Method. However, avoiding synchronization will
625 // probably make the implementation more scalable.
626 private MethodAccessor acquireMethodAccessor() {
627 // First check to see if one has been created yet, and take it
628 // if so
629 MethodAccessor tmp = null;
630 if (root != null) tmp = root.getMethodAccessor();
631 if (tmp != null) {
632 methodAccessor = tmp;
633 } else {
634 // Otherwise fabricate one and propagate it up to the root
635 tmp = reflectionFactory.newMethodAccessor(this);
636 setMethodAccessor(tmp);
637 }
638
639 return tmp;
640 }
641
642 // Returns MethodAccessor for this Method object, not looking up
643 // the chain to the root
644 MethodAccessor getMethodAccessor() {
645 return methodAccessor;
646 }
647
648 // Sets the MethodAccessor for this Method object and
649 // (recursively) its root
650 void setMethodAccessor(MethodAccessor accessor) {
651 methodAccessor = accessor;
652 // Propagate up
653 if (root != null) {
654 root.setMethodAccessor(accessor);
655 }
656 }
657
658 /**
659 * Returns the default value for the annotation member represented by
660 * this {@code Method} instance. If the member is of a primitive type,
661 * an instance of the corresponding wrapper type is returned. Returns
662 * null if no default is associated with the member, or if the method
663 * instance does not represent a declared member of an annotation type.
664 *
665 * @return the default value for the annotation member represented
666 * by this {@code Method} instance.
667 * @throws TypeNotPresentException if the annotation is of type
668 * {@link Class} and no definition can be found for the
669 * default class value.
670 * @since 1.5
671 */
672 public Object getDefaultValue() {
673 if (annotationDefault == null)
674 return null;
675 Class<?> memberType = AnnotationType.invocationHandlerReturnType(
676 getReturnType());
677 Object result = AnnotationParser.parseMemberValue(
678 memberType, ByteBuffer.wrap(annotationDefault),
679 SharedSecrets.getJavaLangAccess().
680 getConstantPool(getDeclaringClass()),
681 getDeclaringClass());
682 if (result instanceof ExceptionProxy) {
683 if (result instanceof TypeNotPresentExceptionProxy) {
684 TypeNotPresentExceptionProxy proxy = (TypeNotPresentExceptionProxy)result;
685 throw new TypeNotPresentException(proxy.typeName(), proxy.getCause());
686 }
687 throw new AnnotationFormatError("Invalid default: " + this);
688 }
689 return result;
690 }
691
692 /**
693 * {@inheritDoc}
694 * @throws NullPointerException {@inheritDoc}
695 * @since 1.5
696 */
697 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
698 return super.getAnnotation(annotationClass);
699 }
700
701 /**
702 * {@inheritDoc}
703 * @since 1.5
704 */
705 public Annotation[] getDeclaredAnnotations() {
706 return super.getDeclaredAnnotations();
707 }
708
709 /**
710 * {@inheritDoc}
711 * @since 1.5
712 */
713 @Override
714 public Annotation[][] getParameterAnnotations() {
715 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
716 }
717
718 /**
719 * {@inheritDoc}
720 * @since 1.8
721 */
722 @Override
723 public AnnotatedType getAnnotatedReturnType() {
724 return getAnnotatedReturnType0(getGenericReturnType());
725 }
726
727 @Override
728 boolean handleParameterNumberMismatch(int resultLength, int numParameters) {
729 throw new AnnotationFormatError("Parameter annotations don't match number of parameters");
730 }
731 }