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 * @since 9
186 */
187 @Override
188 @CallerSensitive
189 public void setAccessible(boolean flag) {
190 AccessibleObject.checkPermission();
191 if (flag) checkCanSetAccessible(Reflection.getCallerClass());
192 setAccessible0(flag);
193 }
194
195 @Override
196 void checkCanSetAccessible(Class<?> caller) {
197 checkCanSetAccessible(caller, clazz);
198 }
199
200 /**
201 * Used by Excecutable for annotation sharing.
202 */
203 @Override
204 Executable getRoot() {
205 return root;
206 }
207
208 @Override
209 boolean hasGenericInformation() {
210 return (getGenericSignature() != null);
211 }
212
213 @Override
214 byte[] getAnnotationBytes() {
215 return annotations;
216 }
217
218 /**
219 * Returns the {@code Class} object representing the class or interface
220 * that declares the method represented by this object.
221 */
222 @Override
223 public Class<?> getDeclaringClass() {
224 return clazz;
225 }
226
227 /**
228 * Returns the name of the method represented by this {@code Method}
229 * object, as a {@code String}.
230 */
231 @Override
232 public String getName() {
233 return name;
234 }
235
236 /**
237 * {@inheritDoc}
238 */
239 @Override
240 public int getModifiers() {
241 return modifiers;
242 }
243
244 /**
245 * {@inheritDoc}
246 * @throws GenericSignatureFormatError {@inheritDoc}
247 * @since 1.5
248 */
249 @Override
250 @SuppressWarnings({"rawtypes", "unchecked"})
251 public TypeVariable<Method>[] getTypeParameters() {
252 if (getGenericSignature() != null)
253 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters();
254 else
255 return (TypeVariable<Method>[])new TypeVariable[0];
256 }
257
258 /**
259 * Returns a {@code Class} object that represents the formal return type
260 * of the method represented by this {@code Method} object.
261 *
262 * @return the return type for the method this object represents
263 */
264 public Class<?> getReturnType() {
265 return returnType;
266 }
267
268 /**
269 * Returns a {@code Type} object that represents the formal return
270 * type of the method represented by this {@code Method} object.
271 *
272 * <p>If the return type is a parameterized type,
273 * the {@code Type} object returned must accurately reflect
274 * the actual type parameters used in the source code.
275 *
276 * <p>If the return type is a type variable or a parameterized type, it
277 * is created. Otherwise, it is resolved.
278 *
279 * @return a {@code Type} object that represents the formal return
280 * type of the underlying method
281 * @throws GenericSignatureFormatError
282 * if the generic method signature does not conform to the format
283 * specified in
284 * <cite>The Java™ Virtual Machine Specification</cite>
285 * @throws TypeNotPresentException if the underlying method's
286 * return type refers to a non-existent type declaration
287 * @throws MalformedParameterizedTypeException if the
288 * underlying method's return typed refers to a parameterized
289 * type that cannot be instantiated for any reason
290 * @since 1.5
291 */
292 public Type getGenericReturnType() {
293 if (getGenericSignature() != null) {
294 return getGenericInfo().getReturnType();
295 } else { return getReturnType();}
296 }
297
298 @Override
299 Class<?>[] getSharedParameterTypes() {
300 return parameterTypes;
301 }
302
303 /**
304 * {@inheritDoc}
305 */
306 @Override
307 public Class<?>[] getParameterTypes() {
308 return parameterTypes.clone();
309 }
310
311 /**
312 * {@inheritDoc}
313 * @since 1.8
314 */
315 public int getParameterCount() { return parameterTypes.length; }
316
317
318 /**
319 * {@inheritDoc}
320 * @throws GenericSignatureFormatError {@inheritDoc}
321 * @throws TypeNotPresentException {@inheritDoc}
322 * @throws MalformedParameterizedTypeException {@inheritDoc}
323 * @since 1.5
324 */
325 @Override
326 public Type[] getGenericParameterTypes() {
327 return super.getGenericParameterTypes();
328 }
329
330 /**
331 * {@inheritDoc}
332 */
333 @Override
334 public Class<?>[] getExceptionTypes() {
335 return exceptionTypes.clone();
336 }
337
338 /**
339 * {@inheritDoc}
340 * @throws GenericSignatureFormatError {@inheritDoc}
341 * @throws TypeNotPresentException {@inheritDoc}
342 * @throws MalformedParameterizedTypeException {@inheritDoc}
343 * @since 1.5
344 */
345 @Override
346 public Type[] getGenericExceptionTypes() {
347 return super.getGenericExceptionTypes();
348 }
349
350 /**
351 * Compares this {@code Method} against the specified object. Returns
352 * true if the objects are the same. Two {@code Methods} are the same if
353 * they were declared by the same class and have the same name
354 * and formal parameter types and return type.
355 */
356 public boolean equals(Object obj) {
357 if (obj != null && obj instanceof Method) {
358 Method other = (Method)obj;
359 if ((getDeclaringClass() == other.getDeclaringClass())
360 && (getName() == other.getName())) {
361 if (!returnType.equals(other.getReturnType()))
362 return false;
363 return equalParamTypes(parameterTypes, other.parameterTypes);
364 }
365 }
366 return false;
367 }
368
369 /**
370 * Returns a hashcode for this {@code Method}. The hashcode is computed
371 * as the exclusive-or of the hashcodes for the underlying
372 * method's declaring class name and the method's name.
373 */
374 public int hashCode() {
375 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
376 }
377
378 /**
379 * Returns a string describing this {@code Method}. The string is
380 * formatted as the method access modifiers, if any, followed by
381 * the method return type, followed by a space, followed by the
382 * class declaring the method, followed by a period, followed by
383 * the method name, followed by a parenthesized, comma-separated
384 * list of the method's formal parameter types. If the method
385 * throws checked exceptions, the parameter list is followed by a
386 * space, followed by the word "{@code throws}" followed by a
387 * comma-separated list of the thrown exception types.
388 * For example:
389 * <pre>
390 * public boolean java.lang.Object.equals(java.lang.Object)
391 * </pre>
392 *
393 * <p>The access modifiers are placed in canonical order as
394 * specified by "The Java Language Specification". This is
395 * {@code public}, {@code protected} or {@code private} first,
396 * and then other modifiers in the following order:
397 * {@code abstract}, {@code default}, {@code static}, {@code final},
398 * {@code synchronized}, {@code native}, {@code strictfp}.
399 *
400 * @return a string describing this {@code Method}
401 *
402 * @jls 8.4.3 Method Modifiers
403 * @jls 9.4 Method Declarations
404 * @jls 9.6.1 Annotation Type Elements
405 */
406 public String toString() {
407 return sharedToString(Modifier.methodModifiers(),
408 isDefault(),
409 parameterTypes,
410 exceptionTypes);
411 }
412
413 @Override
414 void specificToStringHeader(StringBuilder sb) {
415 sb.append(getReturnType().getTypeName()).append(' ');
416 sb.append(getDeclaringClass().getTypeName()).append('.');
417 sb.append(getName());
418 }
419
420 /**
421 * Returns a string describing this {@code Method}, including
422 * type parameters. The string is formatted as the method access
423 * modifiers, if any, followed by an angle-bracketed
424 * comma-separated list of the method's type parameters, if any,
425 * followed by the method's generic return type, followed by a
426 * space, followed by the class declaring the method, followed by
427 * a period, followed by the method name, followed by a
428 * parenthesized, comma-separated list of the method's generic
429 * formal parameter types.
430 *
431 * If this method was declared to take a variable number of
432 * arguments, instead of denoting the last parameter as
433 * "<code><i>Type</i>[]</code>", it is denoted as
434 * "<code><i>Type</i>...</code>".
435 *
436 * A space is used to separate access modifiers from one another
437 * and from the type parameters or return type. If there are no
438 * type parameters, the type parameter list is elided; if the type
439 * parameter list is present, a space separates the list from the
440 * class name. If the method is declared to throw exceptions, the
441 * parameter list is followed by a space, followed by the word
442 * "{@code throws}" followed by a comma-separated list of the generic
443 * thrown exception types.
444 *
445 * <p>The access modifiers are placed in canonical order as
446 * specified by "The Java Language Specification". This is
447 * {@code public}, {@code protected} or {@code private} first,
448 * and then other modifiers in the following order:
449 * {@code abstract}, {@code default}, {@code static}, {@code final},
450 * {@code synchronized}, {@code native}, {@code strictfp}.
451 *
452 * @return a string describing this {@code Method},
453 * include type parameters
454 *
455 * @since 1.5
456 *
457 * @jls 8.4.3 Method Modifiers
458 * @jls 9.4 Method Declarations
459 * @jls 9.6.1 Annotation Type Elements
460 */
461 @Override
462 public String toGenericString() {
463 return sharedToGenericString(Modifier.methodModifiers(), isDefault());
464 }
465
466 @Override
467 void specificToGenericStringHeader(StringBuilder sb) {
468 Type genRetType = getGenericReturnType();
469 sb.append(genRetType.getTypeName()).append(' ');
470 sb.append(getDeclaringClass().getTypeName()).append('.');
471 sb.append(getName());
472 }
473
474 /**
475 * Invokes the underlying method represented by this {@code Method}
476 * object, on the specified object with the specified parameters.
477 * Individual parameters are automatically unwrapped to match
478 * primitive formal parameters, and both primitive and reference
479 * parameters are subject to method invocation conversions as
480 * necessary.
481 *
482 * <p>If the underlying method is static, then the specified {@code obj}
483 * argument is ignored. It may be null.
484 *
485 * <p>If the number of formal parameters required by the underlying method is
486 * 0, the supplied {@code args} array may be of length 0 or null.
487 *
488 * <p>If the underlying method is an instance method, it is invoked
489 * using dynamic method lookup as documented in The Java Language
490 * Specification, Second Edition, section 15.12.4.4; in particular,
491 * overriding based on the runtime type of the target object will occur.
492 *
493 * <p>If the underlying method is static, the class that declared
494 * the method is initialized if it has not already been initialized.
495 *
496 * <p>If the method completes normally, the value it returns is
497 * returned to the caller of invoke; if the value has a primitive
498 * type, it is first appropriately wrapped in an object. However,
499 * if the value has the type of an array of a primitive type, the
500 * elements of the array are <i>not</i> wrapped in objects; in
501 * other words, an array of primitive type is returned. If the
502 * underlying method return type is void, the invocation returns
503 * null.
504 *
505 * @param obj the object the underlying method is invoked from
506 * @param args the arguments used for the method call
507 * @return the result of dispatching the method represented by
508 * this object on {@code obj} with parameters
509 * {@code args}
510 *
511 * @exception IllegalAccessException if this {@code Method} object
512 * is enforcing Java language access control and the underlying
513 * method is inaccessible.
514 * @exception IllegalArgumentException if the method is an
515 * instance method and the specified object argument
516 * is not an instance of the class or interface
517 * declaring the underlying method (or of a subclass
518 * or implementor thereof); if the number of actual
519 * and formal parameters differ; if an unwrapping
520 * conversion for primitive arguments fails; or if,
521 * after possible unwrapping, a parameter value
522 * cannot be converted to the corresponding formal
523 * parameter type by a method invocation conversion.
524 * @exception InvocationTargetException if the underlying method
525 * throws an exception.
526 * @exception NullPointerException if the specified object is null
527 * and the method is an instance method.
528 * @exception ExceptionInInitializerError if the initialization
529 * provoked by this method fails.
530 */
531 @CallerSensitive
532 @ForceInline // to ensure Reflection.getCallerClass optimization
533 @HotSpotIntrinsicCandidate
534 public Object invoke(Object obj, Object... args)
535 throws IllegalAccessException, IllegalArgumentException,
536 InvocationTargetException
537 {
538 if (!override) {
539 Class<?> caller = Reflection.getCallerClass();
540 checkAccess(caller, clazz,
541 Modifier.isStatic(modifiers) ? null : obj.getClass(),
542 modifiers);
543 }
544 MethodAccessor ma = methodAccessor; // read volatile
545 if (ma == null) {
546 ma = acquireMethodAccessor();
547 }
548 return ma.invoke(obj, args);
549 }
550
551 /**
552 * Returns {@code true} if this method is a bridge
553 * method; returns {@code false} otherwise.
554 *
555 * @return true if and only if this method is a bridge
556 * method as defined by the Java Language Specification.
557 * @since 1.5
558 */
559 public boolean isBridge() {
560 return (getModifiers() & Modifier.BRIDGE) != 0;
561 }
562
563 /**
564 * {@inheritDoc}
565 * @since 1.5
566 */
567 @Override
568 public boolean isVarArgs() {
569 return super.isVarArgs();
570 }
571
572 /**
573 * {@inheritDoc}
574 * @jls 13.1 The Form of a Binary
575 * @since 1.5
576 */
577 @Override
578 public boolean isSynthetic() {
579 return super.isSynthetic();
580 }
581
582 /**
583 * Returns {@code true} if this method is a default
584 * method; returns {@code false} otherwise.
585 *
586 * A default method is a public non-abstract instance method, that
587 * is, a non-static method with a body, declared in an interface
588 * type.
589 *
590 * @return true if and only if this method is a default
591 * method as defined by the Java Language Specification.
592 * @since 1.8
593 */
594 public boolean isDefault() {
595 // Default methods are public non-abstract instance methods
596 // declared in an interface.
597 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) ==
598 Modifier.PUBLIC) && getDeclaringClass().isInterface();
599 }
600
601 // NOTE that there is no synchronization used here. It is correct
602 // (though not efficient) to generate more than one MethodAccessor
603 // for a given Method. However, avoiding synchronization will
604 // probably make the implementation more scalable.
605 private MethodAccessor acquireMethodAccessor() {
606 // First check to see if one has been created yet, and take it
607 // if so
608 MethodAccessor tmp = null;
609 if (root != null) tmp = root.getMethodAccessor();
610 if (tmp != null) {
611 methodAccessor = tmp;
612 } else {
613 // Otherwise fabricate one and propagate it up to the root
614 tmp = reflectionFactory.newMethodAccessor(this);
615 setMethodAccessor(tmp);
616 }
617
618 return tmp;
619 }
620
621 // Returns MethodAccessor for this Method object, not looking up
622 // the chain to the root
623 MethodAccessor getMethodAccessor() {
624 return methodAccessor;
625 }
626
627 // Sets the MethodAccessor for this Method object and
628 // (recursively) its root
629 void setMethodAccessor(MethodAccessor accessor) {
630 methodAccessor = accessor;
631 // Propagate up
632 if (root != null) {
633 root.setMethodAccessor(accessor);
634 }
635 }
636
637 /**
638 * Returns the default value for the annotation member represented by
639 * this {@code Method} instance. If the member is of a primitive type,
640 * an instance of the corresponding wrapper type is returned. Returns
641 * null if no default is associated with the member, or if the method
642 * instance does not represent a declared member of an annotation type.
643 *
644 * @return the default value for the annotation member represented
645 * by this {@code Method} instance.
646 * @throws TypeNotPresentException if the annotation is of type
647 * {@link Class} and no definition can be found for the
648 * default class value.
649 * @since 1.5
650 */
651 public Object getDefaultValue() {
652 if (annotationDefault == null)
653 return null;
654 Class<?> memberType = AnnotationType.invocationHandlerReturnType(
655 getReturnType());
656 Object result = AnnotationParser.parseMemberValue(
657 memberType, ByteBuffer.wrap(annotationDefault),
658 SharedSecrets.getJavaLangAccess().
659 getConstantPool(getDeclaringClass()),
660 getDeclaringClass());
661 if (result instanceof ExceptionProxy) {
662 if (result instanceof TypeNotPresentExceptionProxy) {
663 TypeNotPresentExceptionProxy proxy = (TypeNotPresentExceptionProxy)result;
664 throw new TypeNotPresentException(proxy.typeName(), proxy.getCause());
665 }
666 throw new AnnotationFormatError("Invalid default: " + this);
667 }
668 return result;
669 }
670
671 /**
672 * {@inheritDoc}
673 * @throws NullPointerException {@inheritDoc}
674 * @since 1.5
675 */
676 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
677 return super.getAnnotation(annotationClass);
678 }
679
680 /**
681 * {@inheritDoc}
682 * @since 1.5
683 */
684 public Annotation[] getDeclaredAnnotations() {
685 return super.getDeclaredAnnotations();
686 }
687
688 /**
689 * {@inheritDoc}
690 * @since 1.5
691 */
692 @Override
693 public Annotation[][] getParameterAnnotations() {
694 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
695 }
696
697 /**
698 * {@inheritDoc}
699 * @since 1.8
700 */
701 @Override
702 public AnnotatedType getAnnotatedReturnType() {
703 return getAnnotatedReturnType0(getGenericReturnType());
704 }
705
706 @Override
707 void handleParameterNumberMismatch(int resultLength, int numParameters) {
708 throw new AnnotationFormatError("Parameter annotations don't match number of parameters");
709 }
710 }