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 sun.reflect.MethodAccessor; 29 import sun.reflect.Reflection; 30 import sun.reflect.generics.repository.MethodRepository; 31 import sun.reflect.generics.factory.CoreReflectionFactory; 32 import sun.reflect.generics.factory.GenericsFactory; 33 import sun.reflect.generics.scope.MethodScope; 34 import sun.reflect.annotation.AnnotationType; 35 import sun.reflect.annotation.AnnotationParser; 36 import java.lang.annotation.Annotation; 37 import java.lang.annotation.AnnotationFormatError; 38 import java.nio.ByteBuffer; 39 40 /** 41 * A {@code Method} provides information about, and access to, a single method 42 * on a class or interface. The reflected method may be a class method 43 * or an instance method (including an abstract method). 44 * 45 * <p>A {@code Method} permits widening conversions to occur when matching the 46 * actual parameters to invoke with the underlying method's formal 47 * parameters, but it throws an {@code IllegalArgumentException} if a 48 * narrowing conversion would occur. 49 * 50 * @see Member 51 * @see java.lang.Class 52 * @see java.lang.Class#getMethods() 53 * @see java.lang.Class#getMethod(String, Class[]) 54 * @see java.lang.Class#getDeclaredMethods() 55 * @see java.lang.Class#getDeclaredMethod(String, Class[]) 56 * 57 * @author Kenneth Russell 58 * @author Nakul Saraiya 59 */ 60 public final class Method extends Executable { 61 private Class<?> clazz; 62 private int slot; 63 // This is guaranteed to be interned by the VM in the 1.4 64 // reflection implementation 65 private String name; 66 private Class<?> returnType; 67 private Class<?>[] parameterTypes; 68 private Class<?>[] exceptionTypes; 69 private int modifiers; 70 // Generics and annotations support 71 private transient String signature; 72 // generic info repository; lazily initialized 73 private transient MethodRepository genericInfo; 74 private byte[] annotations; 75 private byte[] parameterAnnotations; 76 private byte[] annotationDefault; 77 private volatile MethodAccessor methodAccessor; 78 // For sharing of MethodAccessors. This branching structure is 79 // currently only two levels deep (i.e., one root Method and 80 // potentially many Method objects pointing to it.) 81 private Method root; 82 // This is set by the vm at Method creation 83 private byte[] typeAnnotations; 84 85 // Generics infrastructure 86 private String getGenericSignature() {return signature;} 87 88 // Accessor for factory 89 private GenericsFactory getFactory() { 90 // create scope and factory 91 return CoreReflectionFactory.make(this, MethodScope.make(this)); 92 } 93 94 // Accessor for generic info repository 95 @Override 96 MethodRepository getGenericInfo() { 97 // lazily initialize repository if necessary 98 if (genericInfo == null) { 99 // create and cache generic info repository 100 genericInfo = MethodRepository.make(getGenericSignature(), 101 getFactory()); 102 } 103 return genericInfo; //return cached repository 104 } 105 106 /** 107 * Package-private constructor used by ReflectAccess to enable 108 * instantiation of these objects in Java code from the java.lang 109 * package via sun.reflect.LangReflectAccess. 110 */ 111 Method(Class<?> declaringClass, 112 String name, 113 Class<?>[] parameterTypes, 114 Class<?> returnType, 115 Class<?>[] checkedExceptions, 116 int modifiers, 117 int slot, 118 String signature, 119 byte[] annotations, 120 byte[] parameterAnnotations, 121 byte[] annotationDefault) { 122 this.clazz = declaringClass; 123 this.name = name; 124 this.parameterTypes = parameterTypes; 125 this.returnType = returnType; 126 this.exceptionTypes = checkedExceptions; 127 this.modifiers = modifiers; 128 this.slot = slot; 129 this.signature = signature; 130 this.annotations = annotations; 131 this.parameterAnnotations = parameterAnnotations; 132 this.annotationDefault = annotationDefault; 133 } 134 135 /** 136 * Package-private routine (exposed to java.lang.Class via 137 * ReflectAccess) which returns a copy of this Method. The copy's 138 * "root" field points to this Method. 139 */ 140 Method copy() { 141 // This routine enables sharing of MethodAccessor objects 142 // among Method objects which refer to the same underlying 143 // method in the VM. (All of this contortion is only necessary 144 // because of the "accessibility" bit in AccessibleObject, 145 // which implicitly requires that new java.lang.reflect 146 // objects be fabricated for each reflective call on Class 147 // objects.) 148 Method res = new Method(clazz, name, parameterTypes, returnType, 149 exceptionTypes, modifiers, slot, signature, 150 annotations, parameterAnnotations, annotationDefault); 151 res.root = this; 152 // Might as well eagerly propagate this if already present 153 res.methodAccessor = methodAccessor; 154 155 res.typeAnnotations = typeAnnotations; 156 return res; 157 } 158 159 @Override 160 boolean hasGenericInformation() { 161 return (getGenericSignature() != null); 162 } 163 164 @Override 165 byte[] getAnnotationBytes() { 166 return annotations; 167 } 168 @Override 169 byte[] getTypeAnnotationBytes() { 170 return typeAnnotations; 171 } 172 173 /** 174 * {@inheritDoc} 175 */ 176 @Override 177 public Class<?> getDeclaringClass() { 178 return clazz; 179 } 180 181 /** 182 * Returns the name of the method represented by this {@code Method} 183 * object, as a {@code String}. 184 */ 185 @Override 186 public String getName() { 187 return name; 188 } 189 190 /** 191 * {@inheritDoc} 192 */ 193 @Override 194 public int getModifiers() { 195 return modifiers; 196 } 197 198 /** 199 * {@inheritDoc} 200 * @throws GenericSignatureFormatError {@inheritDoc} 201 * @since 1.5 202 */ 203 @Override 204 @SuppressWarnings({"rawtypes", "unchecked"}) 205 public TypeVariable<Method>[] getTypeParameters() { 206 if (getGenericSignature() != null) 207 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters(); 208 else 209 return (TypeVariable<Method>[])new TypeVariable[0]; 210 } 211 212 /** 213 * Returns a {@code Class} object that represents the formal return type 214 * of the method represented by this {@code Method} object. 215 * 216 * @return the return type for the method this object represents 217 */ 218 public Class<?> getReturnType() { 219 return returnType; 220 } 221 222 /** 223 * Returns a {@code Type} object that represents the formal return 224 * type of the method represented by this {@code Method} object. 225 * 226 * <p>If the return type is a parameterized type, 227 * the {@code Type} object returned must accurately reflect 228 * the actual type parameters used in the source code. 229 * 230 * <p>If the return type is a type variable or a parameterized type, it 231 * is created. Otherwise, it is resolved. 232 * 233 * @return a {@code Type} object that represents the formal return 234 * type of the underlying method 235 * @throws GenericSignatureFormatError 236 * if the generic method signature does not conform to the format 237 * specified in 238 * <cite>The Java™ Virtual Machine Specification</cite> 239 * @throws TypeNotPresentException if the underlying method's 240 * return type refers to a non-existent type declaration 241 * @throws MalformedParameterizedTypeException if the 242 * underlying method's return typed refers to a parameterized 243 * type that cannot be instantiated for any reason 244 * @since 1.5 245 */ 246 public Type getGenericReturnType() { 247 if (getGenericSignature() != null) { 248 return getGenericInfo().getReturnType(); 249 } else { return getReturnType();} 250 } 251 252 /** 253 * {@inheritDoc} 254 */ 255 @Override 256 public Class<?>[] getParameterTypes() { 257 return parameterTypes.clone(); 258 } 259 260 /** 261 * {@inheritDoc} 262 */ 263 public int getParameterCount() { return parameterTypes.length; } 264 265 266 /** 267 * {@inheritDoc} 268 * @throws GenericSignatureFormatError {@inheritDoc} 269 * @throws TypeNotPresentException {@inheritDoc} 270 * @throws MalformedParameterizedTypeException {@inheritDoc} 271 * @since 1.5 272 */ 273 @Override 274 public Type[] getGenericParameterTypes() { 275 return super.getGenericParameterTypes(); 276 } 277 278 /** 279 * {@inheritDoc} 280 */ 281 @Override 282 public Class<?>[] getExceptionTypes() { 283 return exceptionTypes.clone(); 284 } 285 286 /** 287 * {@inheritDoc} 288 * @throws GenericSignatureFormatError {@inheritDoc} 289 * @throws TypeNotPresentException {@inheritDoc} 290 * @throws MalformedParameterizedTypeException {@inheritDoc} 291 * @since 1.5 292 */ 293 @Override 294 public Type[] getGenericExceptionTypes() { 295 return super.getGenericExceptionTypes(); 296 } 297 298 /** 299 * Compares this {@code Method} against the specified object. Returns 300 * true if the objects are the same. Two {@code Methods} are the same if 301 * they were declared by the same class and have the same name 302 * and formal parameter types and return type. 303 */ 304 public boolean equals(Object obj) { 305 if (obj != null && obj instanceof Method) { 306 Method other = (Method)obj; 307 if ((getDeclaringClass() == other.getDeclaringClass()) 308 && (getName() == other.getName())) { 309 if (!returnType.equals(other.getReturnType())) 310 return false; 311 return equalParamTypes(parameterTypes, other.parameterTypes); 312 } 313 } 314 return false; 315 } 316 317 /** 318 * Returns a hashcode for this {@code Method}. The hashcode is computed 319 * as the exclusive-or of the hashcodes for the underlying 320 * method's declaring class name and the method's name. 321 */ 322 public int hashCode() { 323 return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); 324 } 325 326 /** 327 * Returns a string describing this {@code Method}. The string is 328 * formatted as the method access modifiers, if any, followed by 329 * the method return type, followed by a space, followed by the 330 * class declaring the method, followed by a period, followed by 331 * the method name, followed by a parenthesized, comma-separated 332 * list of the method's formal parameter types. If the method 333 * throws checked exceptions, the parameter list is followed by a 334 * space, followed by the word throws followed by a 335 * comma-separated list of the thrown exception types. 336 * For example: 337 * <pre> 338 * public boolean java.lang.Object.equals(java.lang.Object) 339 * </pre> 340 * 341 * <p>The access modifiers are placed in canonical order as 342 * specified by "The Java Language Specification". This is 343 * {@code public}, {@code protected} or {@code private} first, 344 * and then other modifiers in the following order: 345 * {@code abstract}, {@code default}, {@code static}, {@code final}, 346 * {@code synchronized}, {@code native}, {@code strictfp}. 347 * 348 * @return a string describing this {@code Method} 349 * 350 * @jls 8.4.3 Method Modifiers 351 */ 352 public String toString() { 353 return sharedToString(Modifier.methodModifiers(), 354 isDefault(), 355 parameterTypes, 356 exceptionTypes); 357 } 358 359 @Override 360 void specificToStringHeader(StringBuilder sb) { 361 sb.append(getReturnType().getTypeName()).append(' '); 362 sb.append(getDeclaringClass().getTypeName()).append('.'); 363 sb.append(getName()); 364 } 365 366 /** 367 * Returns a string describing this {@code Method}, including 368 * type parameters. The string is formatted as the method access 369 * modifiers, if any, followed by an angle-bracketed 370 * comma-separated list of the method's type parameters, if any, 371 * followed by the method's generic return type, followed by a 372 * space, followed by the class declaring the method, followed by 373 * a period, followed by the method name, followed by a 374 * parenthesized, comma-separated list of the method's generic 375 * formal parameter types. 376 * 377 * If this method was declared to take a variable number of 378 * arguments, instead of denoting the last parameter as 379 * "<tt><i>Type</i>[]</tt>", it is denoted as 380 * "<tt><i>Type</i>...</tt>". 381 * 382 * A space is used to separate access modifiers from one another 383 * and from the type parameters or return type. If there are no 384 * type parameters, the type parameter list is elided; if the type 385 * parameter list is present, a space separates the list from the 386 * class name. If the method is declared to throw exceptions, the 387 * parameter list is followed by a space, followed by the word 388 * throws followed by a comma-separated list of the generic thrown 389 * exception types. 390 * 391 * <p>The access modifiers are placed in canonical order as 392 * specified by "The Java Language Specification". This is 393 * {@code public}, {@code protected} or {@code private} first, 394 * and then other modifiers in the following order: 395 * {@code abstract}, {@code default}, {@code static}, {@code final}, 396 * {@code synchronized}, {@code native}, {@code strictfp}. 397 * 398 * @return a string describing this {@code Method}, 399 * include type parameters 400 * 401 * @since 1.5 402 * 403 * @jls 8.4.3 Method Modifiers 404 */ 405 @Override 406 public String toGenericString() { 407 return sharedToGenericString(Modifier.methodModifiers(), isDefault()); 408 } 409 410 @Override 411 void specificToGenericStringHeader(StringBuilder sb) { 412 Type genRetType = getGenericReturnType(); 413 sb.append(genRetType.getTypeName()).append(' '); 414 sb.append(getDeclaringClass().getTypeName()).append('.'); 415 sb.append(getName()); 416 } 417 418 /** 419 * Invokes the underlying method represented by this {@code Method} 420 * object, on the specified object with the specified parameters. 421 * Individual parameters are automatically unwrapped to match 422 * primitive formal parameters, and both primitive and reference 423 * parameters are subject to method invocation conversions as 424 * necessary. 425 * 426 * <p>If the underlying method is static, then the specified {@code obj} 427 * argument is ignored. It may be null. 428 * 429 * <p>If the number of formal parameters required by the underlying method is 430 * 0, the supplied {@code args} array may be of length 0 or null. 431 * 432 * <p>If the underlying method is an instance method, it is invoked 433 * using dynamic method lookup as documented in The Java Language 434 * Specification, Second Edition, section 15.12.4.4; in particular, 435 * overriding based on the runtime type of the target object will occur. 436 * 437 * <p>If the underlying method is static, the class that declared 438 * the method is initialized if it has not already been initialized. 439 * 440 * <p>If the method completes normally, the value it returns is 441 * returned to the caller of invoke; if the value has a primitive 442 * type, it is first appropriately wrapped in an object. However, 443 * if the value has the type of an array of a primitive type, the 444 * elements of the array are <i>not</i> wrapped in objects; in 445 * other words, an array of primitive type is returned. If the 446 * underlying method return type is void, the invocation returns 447 * null. 448 * 449 * @param obj the object the underlying method is invoked from 450 * @param args the arguments used for the method call 451 * @return the result of dispatching the method represented by 452 * this object on {@code obj} with parameters 453 * {@code args} 454 * 455 * @exception IllegalAccessException if this {@code Method} object 456 * is enforcing Java language access control and the underlying 457 * method is inaccessible. 458 * @exception IllegalArgumentException if the method is an 459 * instance method and the specified object argument 460 * is not an instance of the class or interface 461 * declaring the underlying method (or of a subclass 462 * or implementor thereof); if the number of actual 463 * and formal parameters differ; if an unwrapping 464 * conversion for primitive arguments fails; or if, 465 * after possible unwrapping, a parameter value 466 * cannot be converted to the corresponding formal 467 * parameter type by a method invocation conversion. 468 * @exception InvocationTargetException if the underlying method 469 * throws an exception. 470 * @exception NullPointerException if the specified object is null 471 * and the method is an instance method. 472 * @exception ExceptionInInitializerError if the initialization 473 * provoked by this method fails. 474 */ 475 public Object invoke(Object obj, Object... args) 476 throws IllegalAccessException, IllegalArgumentException, 477 InvocationTargetException 478 { 479 if (!override) { 480 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { 481 Class<?> caller = Reflection.getCallerClass(1); 482 483 checkAccess(caller, clazz, obj, modifiers); 484 } 485 } 486 MethodAccessor ma = methodAccessor; // read volatile 487 if (ma == null) { 488 ma = acquireMethodAccessor(); 489 } 490 return ma.invoke(obj, args); 491 } 492 493 /** 494 * Returns {@code true} if this method is a bridge 495 * method; returns {@code false} otherwise. 496 * 497 * @return true if and only if this method is a bridge 498 * method as defined by the Java Language Specification. 499 * @since 1.5 500 */ 501 public boolean isBridge() { 502 return (getModifiers() & Modifier.BRIDGE) != 0; 503 } 504 505 /** 506 * {@inheritDoc} 507 * @since 1.5 508 */ 509 @Override 510 public boolean isVarArgs() { 511 return super.isVarArgs(); 512 } 513 514 /** 515 * {@inheritDoc} 516 * @jls 13.1 The Form of a Binary 517 * @since 1.5 518 */ 519 @Override 520 public boolean isSynthetic() { 521 return super.isSynthetic(); 522 } 523 524 /** 525 * Returns {@code true} if this method is a default 526 * method; returns {@code false} otherwise. 527 * 528 * A default method is a public non-abstract instance method, that 529 * is, a non-static method with a body, declared in an interface 530 * type. 531 * 532 * @return true if and only if this method is a default 533 * method as defined by the Java Language Specification. 534 * @since 1.8 535 */ 536 public boolean isDefault() { 537 // Default methods are public non-abstract instance methods 538 // declared in an interface. 539 return ((getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) == 540 Modifier.PUBLIC) && getDeclaringClass().isInterface(); 541 } 542 543 // NOTE that there is no synchronization used here. It is correct 544 // (though not efficient) to generate more than one MethodAccessor 545 // for a given Method. However, avoiding synchronization will 546 // probably make the implementation more scalable. 547 private MethodAccessor acquireMethodAccessor() { 548 // First check to see if one has been created yet, and take it 549 // if so 550 MethodAccessor tmp = null; 551 if (root != null) tmp = root.getMethodAccessor(); 552 if (tmp != null) { 553 methodAccessor = tmp; 554 } else { 555 // Otherwise fabricate one and propagate it up to the root 556 tmp = reflectionFactory.newMethodAccessor(this); 557 setMethodAccessor(tmp); 558 } 559 560 return tmp; 561 } 562 563 // Returns MethodAccessor for this Method object, not looking up 564 // the chain to the root 565 MethodAccessor getMethodAccessor() { 566 return methodAccessor; 567 } 568 569 // Sets the MethodAccessor for this Method object and 570 // (recursively) its root 571 void setMethodAccessor(MethodAccessor accessor) { 572 methodAccessor = accessor; 573 // Propagate up 574 if (root != null) { 575 root.setMethodAccessor(accessor); 576 } 577 } 578 579 /** 580 * Returns the default value for the annotation member represented by 581 * this {@code Method} instance. If the member is of a primitive type, 582 * an instance of the corresponding wrapper type is returned. Returns 583 * null if no default is associated with the member, or if the method 584 * instance does not represent a declared member of an annotation type. 585 * 586 * @return the default value for the annotation member represented 587 * by this {@code Method} instance. 588 * @throws TypeNotPresentException if the annotation is of type 589 * {@link Class} and no definition can be found for the 590 * default class value. 591 * @since 1.5 592 */ 593 public Object getDefaultValue() { 594 if (annotationDefault == null) 595 return null; 596 Class<?> memberType = AnnotationType.invocationHandlerReturnType( 597 getReturnType()); 598 Object result = AnnotationParser.parseMemberValue( 599 memberType, ByteBuffer.wrap(annotationDefault), 600 sun.misc.SharedSecrets.getJavaLangAccess(). 601 getConstantPool(getDeclaringClass()), 602 getDeclaringClass()); 603 if (result instanceof sun.reflect.annotation.ExceptionProxy) 604 throw new AnnotationFormatError("Invalid default: " + this); 605 return result; 606 } 607 608 /** 609 * {@inheritDoc} 610 * @throws NullPointerException {@inheritDoc} 611 * @since 1.5 612 */ 613 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 614 return super.getAnnotation(annotationClass); 615 } 616 617 /** 618 * {@inheritDoc} 619 * @since 1.5 620 */ 621 public Annotation[] getDeclaredAnnotations() { 622 return super.getDeclaredAnnotations(); 623 } 624 625 /** 626 * {@inheritDoc} 627 * @since 1.5 628 */ 629 @Override 630 public Annotation[][] getParameterAnnotations() { 631 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 632 } 633 634 /** 635 * {@inheritDoc} 636 * @since 1.8 637 */ 638 @Override 639 public AnnotatedType getAnnotatedReturnType() { 640 return getAnnotatedReturnType0(getGenericReturnType()); 641 } 642 643 @Override 644 void handleParameterNumberMismatch(int resultLength, int numParameters) { 645 throw new AnnotationFormatError("Parameter annotations don't match number of parameters"); 646 } 647 }