1 /* 2 * Copyright (c) 1996, 2013, 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 sun.reflect.CallerSensitive; 30 import sun.reflect.MethodAccessor; 31 import sun.reflect.Reflection; 32 import sun.reflect.generics.repository.MethodRepository; 33 import sun.reflect.generics.factory.CoreReflectionFactory; 34 import sun.reflect.generics.factory.GenericsFactory; 35 import sun.reflect.generics.scope.MethodScope; 36 import sun.reflect.annotation.AnnotationType; 37 import sun.reflect.annotation.AnnotationParser; 38 import java.lang.annotation.Annotation; 39 import java.lang.annotation.AnnotationFormatError; 40 import java.nio.ByteBuffer; 41 42 /** 43 * A {@code Method} provides information about, and access to, a single method 44 * on a class or interface. The reflected method may be a class method 45 * or an instance method (including an abstract method). 46 * 47 * <p>A {@code Method} permits widening conversions to occur when matching the 48 * actual parameters to invoke with the underlying method's formal 49 * parameters, but it throws an {@code IllegalArgumentException} if a 50 * narrowing conversion would occur. 51 * 52 * @see Member 53 * @see java.lang.Class 54 * @see java.lang.Class#getMethods() 55 * @see java.lang.Class#getMethod(String, Class[]) 56 * @see java.lang.Class#getDeclaredMethods() 57 * @see java.lang.Class#getDeclaredMethod(String, Class[]) 58 * 59 * @author Kenneth Russell 60 * @author Nakul Saraiya 61 */ 62 public final class Method extends Executable { 63 private Class<?> clazz; 64 private int slot; 65 // This is guaranteed to be interned by the VM in the 1.4 66 // reflection implementation 67 private String name; 68 private Class<?> returnType; 69 private Class<?>[] parameterTypes; 70 private Class<?>[] exceptionTypes; 71 private int modifiers; 72 // Generics and annotations support 73 private transient String signature; 74 // generic info repository; lazily initialized 75 private transient MethodRepository genericInfo; 76 private byte[] annotations; 77 private byte[] parameterAnnotations; 78 private byte[] annotationDefault; 79 private volatile MethodAccessor methodAccessor; 80 // For sharing of MethodAccessors. This branching structure is 81 // currently only two levels deep (i.e., one root Method and 82 // potentially many Method objects pointing to it.) 83 // 84 // If this branching structure would ever contain cycles, deadlocks can 85 // occur in annotation code. 86 private Method root; 87 88 // Generics infrastructure 89 private String getGenericSignature() {return signature;} 90 91 // Accessor for factory 92 private GenericsFactory getFactory() { 93 // create scope and factory 94 return CoreReflectionFactory.make(this, MethodScope.make(this)); 95 } 96 97 // Accessor for generic info repository 98 @Override 99 MethodRepository getGenericInfo() { 100 // lazily initialize repository if necessary 101 if (genericInfo == null) { 102 // create and cache generic info repository 103 genericInfo = MethodRepository.make(getGenericSignature(), 104 getFactory()); 105 } 106 return genericInfo; //return cached repository 107 } 108 109 /** 110 * Package-private constructor used by ReflectAccess to enable 111 * instantiation of these objects in Java code from the java.lang 112 * package via sun.reflect.LangReflectAccess. 113 */ 114 Method(Class<?> declaringClass, 115 String name, 116 Class<?>[] parameterTypes, 117 Class<?> returnType, 118 Class<?>[] checkedExceptions, 119 int modifiers, 120 int slot, 121 String signature, 122 byte[] annotations, 123 byte[] parameterAnnotations, 124 byte[] annotationDefault) { 125 this.clazz = declaringClass; 126 this.name = name; 127 this.parameterTypes = parameterTypes; 128 this.returnType = returnType; 129 this.exceptionTypes = checkedExceptions; 130 this.modifiers = modifiers; 131 this.slot = slot; 132 this.signature = signature; 133 this.annotations = annotations; 134 this.parameterAnnotations = parameterAnnotations; 135 this.annotationDefault = annotationDefault; 136 } 137 138 /** 139 * Package-private routine (exposed to java.lang.Class via 140 * ReflectAccess) which returns a copy of this Method. The copy's 141 * "root" field points to this Method. 142 */ 143 Method copy() { 144 // This routine enables sharing of MethodAccessor objects 145 // among Method objects which refer to the same underlying 146 // method in the VM. (All of this contortion is only necessary 147 // because of the "accessibility" bit in AccessibleObject, 148 // which implicitly requires that new java.lang.reflect 149 // objects be fabricated for each reflective call on Class 150 // objects.) 151 if (this.root != null) 152 throw new IllegalArgumentException("Can not copy a non-root Method"); 153 154 Method res = new Method(clazz, name, parameterTypes, returnType, 155 exceptionTypes, modifiers, slot, signature, 156 annotations, parameterAnnotations, annotationDefault); 157 res.root = this; 158 // Might as well eagerly propagate this if already present 159 res.methodAccessor = methodAccessor; 160 return res; 161 } 162 163 /** 164 * Used by Excecutable for annotation sharing. 165 */ 166 @Override 167 Executable getRoot() { 168 return root; 169 } 170 171 @Override 172 boolean hasGenericInformation() { 173 return (getGenericSignature() != null); 174 } 175 176 @Override 177 byte[] getAnnotationBytes() { 178 return annotations; 179 } 180 181 /** 182 * {@inheritDoc} 183 */ 184 @Override 185 public Class<?> getDeclaringClass() { 186 return clazz; 187 } 188 189 /** 190 * Returns the name of the method represented by this {@code Method} 191 * object, as a {@code String}. 192 */ 193 @Override 194 public String getName() { 195 return name; 196 } 197 198 /** 199 * {@inheritDoc} 200 */ 201 @Override 202 public int getModifiers() { 203 return modifiers; 204 } 205 206 /** 207 * {@inheritDoc} 208 * @throws GenericSignatureFormatError {@inheritDoc} 209 * @since 1.5 210 */ 211 @Override 212 @SuppressWarnings({"rawtypes", "unchecked"}) 213 public TypeVariable<Method>[] getTypeParameters() { 214 if (getGenericSignature() != null) 215 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters(); 216 else 217 return (TypeVariable<Method>[])new TypeVariable[0]; 218 } 219 220 /** 221 * Returns a {@code Class} object that represents the formal return type 222 * of the method represented by this {@code Method} object. 223 * 224 * @return the return type for the method this object represents 225 */ 226 public Class<?> getReturnType() { 227 return returnType; 228 } 229 230 /** 231 * Returns a {@code Type} object that represents the formal return 232 * type of the method represented by this {@code Method} object. 233 * 234 * <p>If the return type is a parameterized type, 235 * the {@code Type} object returned must accurately reflect 236 * the actual type parameters used in the source code. 237 * 238 * <p>If the return type is a type variable or a parameterized type, it 239 * is created. Otherwise, it is resolved. 240 * 241 * @return a {@code Type} object that represents the formal return 242 * type of the underlying method 243 * @throws GenericSignatureFormatError 244 * if the generic method signature does not conform to the format 245 * specified in 246 * <cite>The Java™ Virtual Machine Specification</cite> 247 * @throws TypeNotPresentException if the underlying method's 248 * return type refers to a non-existent type declaration 249 * @throws MalformedParameterizedTypeException if the 250 * underlying method's return typed refers to a parameterized 251 * type that cannot be instantiated for any reason 252 * @since 1.5 253 */ 254 public Type getGenericReturnType() { 255 if (getGenericSignature() != null) { 256 return getGenericInfo().getReturnType(); 257 } else { return getReturnType();} 258 } 259 260 /** 261 * {@inheritDoc} 262 */ 263 @Override 264 public Class<?>[] getParameterTypes() { 265 return parameterTypes.clone(); 266 } 267 268 /** 269 * {@inheritDoc} 270 * @since 1.8 271 */ 272 public int getParameterCount() { return parameterTypes.length; } 273 274 275 /** 276 * {@inheritDoc} 277 * @throws GenericSignatureFormatError {@inheritDoc} 278 * @throws TypeNotPresentException {@inheritDoc} 279 * @throws MalformedParameterizedTypeException {@inheritDoc} 280 * @since 1.5 281 */ 282 @Override 283 public Type[] getGenericParameterTypes() { 284 return super.getGenericParameterTypes(); 285 } 286 287 /** 288 * {@inheritDoc} 289 */ 290 @Override 291 public Class<?>[] getExceptionTypes() { 292 return exceptionTypes.clone(); 293 } 294 295 /** 296 * {@inheritDoc} 297 * @throws GenericSignatureFormatError {@inheritDoc} 298 * @throws TypeNotPresentException {@inheritDoc} 299 * @throws MalformedParameterizedTypeException {@inheritDoc} 300 * @since 1.5 301 */ 302 @Override 303 public Type[] getGenericExceptionTypes() { 304 return super.getGenericExceptionTypes(); 305 } 306 307 /** 308 * Compares this {@code Method} against the specified object. Returns 309 * true if the objects are the same. Two {@code Methods} are the same if 310 * they were declared by the same class and have the same name 311 * and formal parameter types and return type. 312 */ 313 public boolean equals(Object obj) { 314 if (obj != null && obj instanceof Method) { 315 Method other = (Method)obj; 316 if ((getDeclaringClass() == other.getDeclaringClass()) 317 && (getName() == other.getName())) { 318 if (!returnType.equals(other.getReturnType())) 319 return false; 320 return equalParamTypes(parameterTypes, other.parameterTypes); 321 } 322 } 323 return false; 324 } 325 326 /** 327 * Returns a hashcode for this {@code Method}. The hashcode is computed 328 * as the exclusive-or of the hashcodes for the underlying 329 * method's declaring class name and the method's name. 330 */ 331 public int hashCode() { 332 return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); 333 } 334 335 /** 336 * Returns a string describing this {@code Method}. The string is 337 * formatted as the method access modifiers, if any, followed by 338 * the method return type, followed by a space, followed by the 339 * class declaring the method, followed by a period, followed by 340 * the method name, followed by a parenthesized, comma-separated 341 * list of the method's formal parameter types. If the method 342 * throws checked exceptions, the parameter list is followed by a 343 * space, followed by the word throws followed by a 344 * comma-separated list of the thrown exception types. 345 * For example: 346 * <pre> 347 * public boolean java.lang.Object.equals(java.lang.Object) 348 * </pre> 349 * 350 * <p>The access modifiers are placed in canonical order as 351 * specified by "The Java Language Specification". This is 352 * {@code public}, {@code protected} or {@code private} first, 353 * and then other modifiers in the following order: 354 * {@code abstract}, {@code default}, {@code static}, {@code final}, 355 * {@code synchronized}, {@code native}, {@code strictfp}. 356 * 357 * @return a string describing this {@code Method} 358 * 359 * @jls 8.4.3 Method Modifiers 360 * @jls 9.4 Method Declarations 361 * @jls 9.6.1 Annotation Type Elements 362 */ 363 public String toString() { 364 return sharedToString(Modifier.methodModifiers(), 365 isDefault(), 366 parameterTypes, 367 exceptionTypes); 368 } 369 370 @Override 371 void specificToStringHeader(StringBuilder sb) { 372 sb.append(getReturnType().getTypeName()).append(' '); 373 sb.append(getDeclaringClass().getTypeName()).append('.'); 374 sb.append(getName()); 375 } 376 377 /** 378 * Returns a string describing this {@code Method}, including 379 * type parameters. The string is formatted as the method access 380 * modifiers, if any, followed by an angle-bracketed 381 * comma-separated list of the method's type parameters, if any, 382 * followed by the method's generic return type, followed by a 383 * space, followed by the class declaring the method, followed by 384 * a period, followed by the method name, followed by a 385 * parenthesized, comma-separated list of the method's generic 386 * formal parameter types. 387 * 388 * If this method was declared to take a variable number of 389 * arguments, instead of denoting the last parameter as 390 * "<tt><i>Type</i>[]</tt>", it is denoted as 391 * "<tt><i>Type</i>...</tt>". 392 * 393 * A space is used to separate access modifiers from one another 394 * and from the type parameters or return type. If there are no 395 * type parameters, the type parameter list is elided; if the type 396 * parameter list is present, a space separates the list from the 397 * class name. If the method is declared to throw exceptions, the 398 * parameter list is followed by a space, followed by the word 399 * throws followed by a comma-separated list of the generic thrown 400 * exception types. 401 * 402 * <p>The access modifiers are placed in canonical order as 403 * specified by "The Java Language Specification". This is 404 * {@code public}, {@code protected} or {@code private} first, 405 * and then other modifiers in the following order: 406 * {@code abstract}, {@code default}, {@code static}, {@code final}, 407 * {@code synchronized}, {@code native}, {@code strictfp}. 408 * 409 * @return a string describing this {@code Method}, 410 * include type parameters 411 * 412 * @since 1.5 413 * 414 * @jls 8.4.3 Method Modifiers 415 * @jls 9.4 Method Declarations 416 * @jls 9.6.1 Annotation Type Elements 417 */ 418 @Override 419 public String toGenericString() { 420 return sharedToGenericString(Modifier.methodModifiers(), isDefault()); 421 } 422 423 @Override 424 void specificToGenericStringHeader(StringBuilder sb) { 425 Type genRetType = getGenericReturnType(); 426 sb.append(genRetType.getTypeName()).append(' '); 427 sb.append(getDeclaringClass().getTypeName()).append('.'); 428 sb.append(getName()); 429 } 430 431 /** 432 * Invokes the underlying method represented by this {@code Method} 433 * object, on the specified object with the specified parameters. 434 * Individual parameters are automatically unwrapped to match 435 * primitive formal parameters, and both primitive and reference 436 * parameters are subject to method invocation conversions as 437 * necessary. 438 * 439 * <p>If the underlying method is static, then the specified {@code obj} 440 * argument is ignored. It may be null. 441 * 442 * <p>If the number of formal parameters required by the underlying method is 443 * 0, the supplied {@code args} array may be of length 0 or null. 444 * 445 * <p>If the underlying method is an instance method, it is invoked 446 * using dynamic method lookup as documented in The Java Language 447 * Specification, Second Edition, section 15.12.4.4; in particular, 448 * overriding based on the runtime type of the target object will occur. 449 * 450 * <p>If the underlying method is static, the class that declared 451 * the method is initialized if it has not already been initialized. 452 * 453 * <p>If the method completes normally, the value it returns is 454 * returned to the caller of invoke; if the value has a primitive 455 * type, it is first appropriately wrapped in an object. However, 456 * if the value has the type of an array of a primitive type, the 457 * elements of the array are <i>not</i> wrapped in objects; in 458 * other words, an array of primitive type is returned. If the 459 * underlying method return type is void, the invocation returns 460 * null. 461 * 462 * @param obj the object the underlying method is invoked from 463 * @param args the arguments used for the method call 464 * @return the result of dispatching the method represented by 465 * this object on {@code obj} with parameters 466 * {@code args} 467 * 468 * @exception IllegalAccessException if this {@code Method} object 469 * is enforcing Java language access control and the underlying 470 * method is inaccessible. 471 * @exception IllegalArgumentException if the method is an 472 * instance method and the specified object argument 473 * is not an instance of the class or interface 474 * declaring the underlying method (or of a subclass 475 * or implementor thereof); if the number of actual 476 * and formal parameters differ; if an unwrapping 477 * conversion for primitive arguments fails; or if, 478 * after possible unwrapping, a parameter value 479 * cannot be converted to the corresponding formal 480 * parameter type by a method invocation conversion. 481 * @exception InvocationTargetException if the underlying method 482 * throws an exception. 483 * @exception NullPointerException if the specified object is null 484 * and the method is an instance method. 485 * @exception ExceptionInInitializerError if the initialization 486 * provoked by this method fails. 487 */ 488 @CallerSensitive 489 @HotSpotIntrinsicCandidate 490 public Object invoke(Object obj, Object... args) 491 throws IllegalAccessException, IllegalArgumentException, 492 InvocationTargetException 493 { 494 if (!override) { 495 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { 496 Class<?> caller = Reflection.getCallerClass(); 497 checkAccess(caller, clazz, obj, modifiers); 498 } 499 } 500 MethodAccessor ma = methodAccessor; // read volatile 501 if (ma == null) { 502 ma = acquireMethodAccessor(); 503 } 504 return ma.invoke(obj, args); 505 } 506 507 /** 508 * Returns {@code true} if this method is a bridge 509 * method; returns {@code false} otherwise. 510 * 511 * @return true if and only if this method is a bridge 512 * method as defined by the Java Language Specification. 513 * @since 1.5 514 */ 515 public boolean isBridge() { 516 return (getModifiers() & Modifier.BRIDGE) != 0; 517 } 518 519 /** 520 * {@inheritDoc} 521 * @since 1.5 522 */ 523 @Override 524 public boolean isVarArgs() { 525 return super.isVarArgs(); 526 } 527 528 /** 529 * {@inheritDoc} 530 * @jls 13.1 The Form of a Binary 531 * @since 1.5 532 */ 533 @Override 534 public boolean isSynthetic() { 535 return super.isSynthetic(); 536 } 537 538 /** 539 * Returns {@code true} if this method is a default 540 * method; returns {@code false} otherwise. 541 * 542 * A default method is a public non-abstract instance method, that 543 * is, a non-static method with a body, declared in an interface 544 * type. 545 * 546 * @return true if and only if this method is a default 547 * method as defined by the Java Language Specification. 548 * @since 1.8 549 */ 550 public boolean isDefault() { 551 // Default methods are public non-abstract instance methods 552 // declared in an interface. 553 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) == 554 Modifier.PUBLIC) && getDeclaringClass().isInterface(); 555 } 556 557 // NOTE that there is no synchronization used here. It is correct 558 // (though not efficient) to generate more than one MethodAccessor 559 // for a given Method. However, avoiding synchronization will 560 // probably make the implementation more scalable. 561 private MethodAccessor acquireMethodAccessor() { 562 // First check to see if one has been created yet, and take it 563 // if so 564 MethodAccessor tmp = null; 565 if (root != null) tmp = root.getMethodAccessor(); 566 if (tmp != null) { 567 methodAccessor = tmp; 568 } else { 569 // Otherwise fabricate one and propagate it up to the root 570 tmp = reflectionFactory.newMethodAccessor(this); 571 setMethodAccessor(tmp); 572 } 573 574 return tmp; 575 } 576 577 // Returns MethodAccessor for this Method object, not looking up 578 // the chain to the root 579 MethodAccessor getMethodAccessor() { 580 return methodAccessor; 581 } 582 583 // Sets the MethodAccessor for this Method object and 584 // (recursively) its root 585 void setMethodAccessor(MethodAccessor accessor) { 586 methodAccessor = accessor; 587 // Propagate up 588 if (root != null) { 589 root.setMethodAccessor(accessor); 590 } 591 } 592 593 /** 594 * Returns the default value for the annotation member represented by 595 * this {@code Method} instance. If the member is of a primitive type, 596 * an instance of the corresponding wrapper type is returned. Returns 597 * null if no default is associated with the member, or if the method 598 * instance does not represent a declared member of an annotation type. 599 * 600 * @return the default value for the annotation member represented 601 * by this {@code Method} instance. 602 * @throws TypeNotPresentException if the annotation is of type 603 * {@link Class} and no definition can be found for the 604 * default class value. 605 * @since 1.5 606 */ 607 public Object getDefaultValue() { 608 if (annotationDefault == null) 609 return null; 610 Class<?> memberType = AnnotationType.invocationHandlerReturnType( 611 getReturnType()); 612 Object result = AnnotationParser.parseMemberValue( 613 memberType, ByteBuffer.wrap(annotationDefault), 614 sun.misc.SharedSecrets.getJavaLangAccess(). 615 getConstantPool(getDeclaringClass()), 616 getDeclaringClass()); 617 if (result instanceof sun.reflect.annotation.ExceptionProxy) 618 throw new AnnotationFormatError("Invalid default: " + this); 619 return result; 620 } 621 622 /** 623 * {@inheritDoc} 624 * @throws NullPointerException {@inheritDoc} 625 * @since 1.5 626 */ 627 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 628 return super.getAnnotation(annotationClass); 629 } 630 631 /** 632 * {@inheritDoc} 633 * @since 1.5 634 */ 635 public Annotation[] getDeclaredAnnotations() { 636 return super.getDeclaredAnnotations(); 637 } 638 639 /** 640 * {@inheritDoc} 641 * @since 1.5 642 */ 643 @Override 644 public Annotation[][] getParameterAnnotations() { 645 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 646 } 647 648 /** 649 * {@inheritDoc} 650 * @since 1.8 651 */ 652 @Override 653 public AnnotatedType getAnnotatedReturnType() { 654 return getAnnotatedReturnType0(getGenericReturnType()); 655 } 656 657 @Override 658 void handleParameterNumberMismatch(int resultLength, int numParameters) { 659 throw new AnnotationFormatError("Parameter annotations don't match number of parameters"); 660 } 661 }